Part I - Mexico

Plants of Northeastern Mexico with ornamental potential for South Texas

Table of Contents

Part I

The Palms of Northeastern Mexico (excluding Brahea) The Cycads of Northeastern Mexico Agaves in Northeastern Mexico Two interesting cacti from the Tamaulipan thorn scrub A pair of vines from the Sierra Madre and adjacent thorn scrub Some ornamental flowering shrubs from NE Mexico

Richard Travis Copyright 2003

Vol. 8, No. 1

INTRODUCTION The hardest part about writing these two issues was not where to start but rather where to stop. To do justice to all the interesting plants in Northeastern Mexico would require many more volumes and much more labor, so I have tried to limit these publications to the palms and many of the plants that might interest the palm enthusiast in the southern areas of Texas, from Brownsville to the Coastal Bend and, to a lesser degree, the San Antonio/Austin areas. That would include many of the other large monocots such as agaves and yuccas, as well as some interesting subtropical trees, shrubs and vines that have particular potential for the South Texas landscape. Excluding the palms, I have for the most part not included plants which are known to occur naturally north of the Rio Grande. Our native Texas plants have already been covered ad nauseam by a number of preachy native plant books. The intention here was to focus on the wonderful flora which comes from our neighbors to the south.

Coming up with a definition of Northeastern Mexico was also not easy, from early on I decided that it would include the lowlands and warmer mountain regions north of the Tropic of Cancer up to eastern Coahuila; in other words, the part of NE Mexico that has a climate closest to that of southern and southcentral Texas. This includes the thorn scrub of central and northern Tamaulipas and Nuevo Leon north of a Ciudad Victoria-Soto la Marina line, plus the lower and mid-level elevations of the Sierra Madre which are not too cool and humid. There may be one or two important exceptions to this, but if you extend the range too much beyond the prescribed area you’re asking for trouble. South of the tropic, for instance, you enter a region that is free from heavy frosts (and tends to be considerably wetter), and too far west and conditions become too dry and lack the higher humidity seen closer to the coast. Still, within these imposed boundaries lies an unbelievably diverse flora, especially considering that this area shares our fairly severe Texas climate of heat and frost, drought and damp. This region has become the richest source of recent plant introductions for much of Texas, and will likely continue to be so for quite some time to come.

The palms of course receive the most thorough scrutinizing in this book, especially the obscure and difficult braheas (which will wait until Part II). But even if you are not immediately interested in, say, the dasylirions or agaves, you may in the future decide that the garden could use something a little different.

And hopefully these articles will prove of some use to those who travel down to NE Mexico on occasion and want to know what a certain plant may be. Whatever the case, I hope you enjoy these issues as much as I have enjoyed preparing it. It has been over a year in the making (actually a few of these pictures date back nearly a decade) and going on a dozen trips to the region since December 2002. I would have loved to include a number of trees from the Sierra Madre, particularly the oaks, or some of the interesting monocots such as Beschorneria, but they seem to be plants better suited for more temperate climates. Central Texas is likely a superior area for many of these montane plants, which probably have little chance of long-term success in deep South Texas. For that reason most have not been included here. Maybe in the future.

ACKNOWLEDGMENTS My first trip to Mexico was in August of 1989 to Monterrey, my grandmother and I took the train there for a weekend adventure. During the quick trip, we managed to get in a visit to Horsetail Falls and the recently flooded Huasteca Canyon. Less than a year later, Lynn Lowery invited me to go with him and his son-in-law Mike Anderson to go see Brahea “bella” in Coahuila. It was a wonderful trip, and really got me hooked on Mexico. Much of the flora of NE Mexico would still be rare in Texas gardens today would it have not been for the late Lynn Lowery. Lynn was the first great Texas horticulturist who saw the enormous potential that NE Mexico held for plant material. We all miss Lynn very much and are grateful for his contributions and inspiration.

Undoubtedly the most helpful person in preparing this publication was Carl Max Schoenfeld of Yuccado Nursery in Hempstead (henceforth referred to as Carl), he was by far the best source of information on the vegetation of the area and offered me a tremendous amount of help. It seemed like a week didn’t go by this summer that I didn’t call him up trying to extract just one more piece of information out of him. Thanks also to Wade at Yucca-do and John Fairey at Peckerwood Gardens, many plants in this book which were not photographed in the wild came from their gardens. Also gracias to Greg Starr and Matt Johnson of Tucson, Don Hodel and Dr. Hermilo Quero for their help on the braheas, Bruce Erickson of California for his help in finding Brahea moorei above Ciudad Victoria, Drs. David Bogler and Luis Hernandez with their assistance on the dasylirions and nolinas respectively, RL Frasier for coming along on all the trips (good and bad), and Avis Delgado for holding down the fort and rescuing the Honda down in San Fernando.

The Palms of Northeastern Mexico (excluding Brahea) Mexico has a number of native palms and cycads, most of which occur in the humid low tropical regions of the country. But many of Mexico’s most distinctive and well-known palms, however, come from the subtropical or drier areas of the country. Immediately the Blue palm ( Brahea armata) and Mexican fan palm (Washingtonia robusta ) come to mind. In extratropical NE Mexico there are only three native palms not in the genus Brahea, although one more species occurs just inside the tropics south of Ciudad Victoria and Soto la Marina. In this issue we will look at the palms and cycads of the region excluding the very special (and complicated) braheas, which will be saved for Part Two.

Sabal mexicana - in contrast to the mountain-dwelling braheas, the sabals of NE Mexico generally prefer lower

moist areas, though in certain places they will grow into the mountains. Near the Texas border, S. mexicana is shorter and stockier, but farther south where the rainfall gets higher the trees tend to have taller thinner trunks.

This may be due to the generally higher forest canopy and the lack of extremely high winds as you back away from the coast. Wherever they grow in numbers, the savannas or forests they form are beautifully scenic.

Perhaps the most memorable grove of Mexican palmetto is on the road south of Soto la Marina, towards Aldama.

In one area near San Jose de las Rusias there is a true forest of them where they grow by the multi-thousands. The looming peaks of the Sierra de Tamaulipas in the background only enhance the exotic tropical look of this spot.

In other areas you can find numerous large trees in what appear to be fairly dry areas, such as east of Ciudad Victoria near their airport. There, tall trees often grow right in the middle of apparently arid plains, it would seem that there is some underground water source in the area. Some of the nicest trees in Tamaulipas are around Gomez Farias, here the sabals are tall, slender and attractive. Every major population you come across in the region appears just so slightly different from the previous, but always easily recognized as S. mexicana.

A number of the forms that grow in the mountains appear particularly distinct. They are frequently found in the Sierra Madre in southern Tamaulipas, where they sometimes grow with Acrocomia, but there are a few pockets of them in the mountains farther north, particularly near Villa Maneiro where Sabal minor is also common and Dioon edule grows in large numbers. A few are (incredibly) able to grow in the colonies of Dioon edule where there is nothing but bare shale. Another notable mountain population can be found east of Tula in oak forest.

Sabal mexicana Right - near Gomez Farias Below - near Ciudad Victoria

Sabal mexicana in the Sierra Madre, near Villa Mainero

Sabal minor (Mexican minor) - this palm is a real oddity of Northeastern Mexico. Sabal minor is a common

palm of the southern United States but is absent south of Central Texas. Until recently, S. minor had never been described south of the border. But a few years ago, in Principes, it was described from Santa Rosa Canyon near Linares, and Carl Schoenfeld and John Fairey found it in large numbers near Villa Maneiro and in the mountains west of Santa Engracia. Yucca-do nursery has since introduced it into cultivation. The rarity of the thing peaked my interest in this little palm, and in February 2003 R.L. Frasier and I set off to Villa Maneiro to find it, along with the brahea from the area they simply call the silverback brahea.

Carl had described this sabal as distinct from the S. minor known in the United States; specifically, he stated that the leaves were larger than populations of S. minor seen in the United States and, more remarkably, that it had an actual subterranean trunk and would “run� under the ground not too unlike Brahea decumbens. Our primary interest in the area was the silverback brahea, and Carl had given us specific directions of where to find it, apparently it was down a dirt road a few miles west of town in the mountains. Also in the area was supposed to be a massive colony of many old Dioon edule . Lynn Lowery had first told me of this population years ago.

Upon leaving Villa Maneiro we climbed a kind of small mesa, very rocky, and soon enough we did in fact come across a good number of Dioon (though nothing like what was ahead). When we arrived to the general area of where I thought the brahea would be we could not find it anywhere (due to a missed turn we were on the completely wrong road. I did indeed find the brahea in July 2003). A few sabals had appeared before this, but they simply looked like young plants of Sabal mexicana. By this time we had entered a small narrow canyon and there were no traces of anything remotely resembling a brahea. The general vicinity appeared noticeably drier than the lush and dramatically beautiful Santa Rosa Canyon just to the north. There are no bromeliads scattered on the canyon walls (though a few interesting barrel cacti are seen), the forest is thinner and drier here, and conditions seem a bit more strenuous. After following the creek for a ways, the main road veered off to the left (the wrong road!). By now these small sabals were everywhere, and even tall S. mexicana was seen in spots, that is not typical in the Sierra Madre, especially considering that this is not exactly the wettest area in Northeastern Mexico.

Evidently the climate quickly gets colder here even though the elevation has not changed much. The few subtropical trees which were seen around Maneiro are now gone, and frost had obviously been here the past

winter judging by the browned banana and papaya plants, which had not been injured back on the plains.

Carl had told me this was an excellent area for plant collecting, particularly for Central Texas, the climate is pretty similar. The vegetation here does, in fact, look something like the Texas Hill Country or parts of the oak country in extreme southern Arizona, only with little sabals and cycads everywhere amongst the oaks.

Before long we found a sabal which had been growing along the edge of an arroyo, where some of the dirt underneath had washed away, and sure enough, there it was, you could easily see this creeping horizontal stem which had been growing for several feet below the ground. It is highly reminiscent of the stems of old Brahea decumbens (or B. moorei, as I later saw on the road to Puerto Purificacion). Speaking of braheas, at one point we stopped when we saw a beautiful lone blue Brahea berlandieri at the edge of a field, it almost looked like someone had planted a B. armata there deliberately. I went over and took a picture of it, but found no evidence of similar looking plants around. I don’t know if most of the B. berlandieri in this area are bluer than most or not, when you only see one large plant it’s hard to get any idea. There was also what appeared to have been a single plant of B. moorei in a shady ditch at this same general spot.

UPDATE: On my subsequent trip back to Villa Mainero in July 2003, after I had figured out the correct road to take, we went back into the Sierra Madre on another road that went a bit farther west and north than the previous. It’s a shame we missed this other road, it has some of the most impressive scenery in northern Mexico and surely one of the most stunning cycad habitats in the Western Hemisphere. Sabal minor continues to be abundant on this road as well. This area is much nicer to visit in the summertime after some rain, and has an abundance of plants that do particularly well in Central Texas ( Quercus polymorpha, Platanus mexicana, etc.). As of December 2003 I have also found it growing west of Cd. Victoria.

It must be noted that, yes, under cultivation the plants do indeed grow very large for S. minor (at least at Peckerwood Gardens). In the shade with good moisture they get especially large. For this reason it has become popular among collectors in the colder palm-growing areas of the U.S. and elsewhere.

Sabal minor Above - in drier country near Villa Mainero Left - in cloud forest at Puerto Purificacion

Sabal minor Upper left - fruiting at Peckerwood Above - in lower areas on the road to Puerto Purificacion Left - in dry country with Dioon edule, near Villa Mainero

Chamaedorea radicalis - this wonderful bamboo palm grows in surprisingly temperate areas in NE Mexico, al-

ways in the Sierra Madre. It is a palm with a wide native range, covering much latitude in eastern Mexico, and the populations are variable in their height and especially leaf thickness, the nicest forms having very thick dark green leaves. It is reported to grow as far north as Nuevo Leon, perhaps in Santa Rosa Canyon but certainly on the road to Puerto Purificacion in the mountains south of Hidalgo. It grows rather abundantly in one spot on the mountain pass above Ciudad Victoria, near the best groves of Brahea moorei . If you blink you’ll miss it. Perhaps the easiest place to see it is farther south around Ocampo, where it is abundant in the subtropical Beaucarnea recurvata forest, and also higher up in the oak forest west of Ocampo. If you take the difficult old logging road to Puerto Purificacion you can see it both at low elevations, where it tends to be hidden away in the summer, all the way up to the cloud forest, where it is easier to spot. It seemed both to me and RL Frasier that the plants from Ocampo had slightly thicker leaves than the ones seen around Puerto Purificacion, though that could have been from environmental factors. You also see it in places where you would certainly expect it, such as west of Valles down in San Luis Potosi. In cultivation it is a fairly well known palm.

In South Texas it does best in areas that have well drained soils which do not accumulate high salt levels. Like many plants from NE Mexico which grow in the mountains but never on the coastal plains, this palm seems to prefer the general growing conditions of Central Texas over that of the more tropical South Texas (it will nevertheless survive here under good conditions). It is cultivated in other subtropical parts of the world as well. At El Cielo and elsewhere the leaves are cut for use in floral shops in Mexico. Chamaedorea microspadix would be the next closest bamboo palm found in eastern Mexico, and it is definitely not as tolerant to the more severe conditions that are found in most of NE Mexico. At any rate Chamaedorea radicalis is a gem of the Sierra Madre Oriental, and would have to rank right up there with Brahea moorei as one of the best horticultural palms from the region.

C. radicalis in seasonally dry forest near Ocampo

Chamaedorea radicalis at Puerto Purificacion

Peckerwood Gardens

Chamaedorea radicalis, a robust form cultivated in Cd. Victoria

Acrocomia mexicana - in its native habitat this spiny feather palm occurs only south of the Tropic of

Cancer as far as anyone knows, though I suppose some renegade plants could exist north of the tropic line, who knows? At any rate it can be seen around Gomez Farias in the mountains and southwards, and is abundant near Tampico near the coast, growing among the very attractive live oaks ( Quercus oleoides ) found east of town. There is a coastal population near the beach east of Aldama, and it can be seen scattered through the countryside north of Aldama where it may be naturalized. West of Ocampo it is present in the forest before you begin the ascent into the Sierra Madre towards Tula. The most impressive place to see them is in the forests on the road to Ciudad del Maiz near the Tamaulipas/San Luis Potosi border.

It is also possible to see it naturalizing on the grounds of the wonderful old Hacienda Santa Engracia northwest of Cd. Victoria (a beautiful place to stay by the way). Their presence there brings up the slight possibility that there may be some remote wild populations outside the tropics which may have gone unnoticed, if not truly native then at least naturalized. As most palm growers know, the acrocomias, of course, are very hard to get started due to the impenetrable nature of the seed, though once going they’re relatively easy to grow. If an easy way could be found to germinate the seed it would make an excellent palm for the Lower Rio Grande Valley. Much debate has arisen lately over the nomenclature of the acrocomias. Henderson, of course, has lumped all the trunked forms into A. aculeata , and if this holds up the name A. mexicana is no longer valid. In South Texas it certainly seems distinct from the other cultivated acrocomia here, the Argentine A. totai, which has longer spines (especially on the trunk) and a less attractive leaf crown.

Acrocomia mexicana (aculeata), on the grounds of the Hacienda Santa Engracia, north of Ciudad Victoria

Acrocomia mexicana (aculeata), west of Ocampo (above), cultivated near Harlingen (left)

The Cycads of Northeastern Mexico In contrast to the palms, there is really only one cycad, Dioon edule , which exists outside of the tropics in Northeastern Mexico (though some botanists are ready to split D. edule into at least two new species. Personally almost all the dioons look alike to me). This tough plant is one of the hardiest cycads around and is pretty easy to grow, though don’t expect it to get large any time soon; in fact, it once made it into the Guiness Book of World Records as the slowest growing plant on earth. As a CITES plant it is of course illegal to import specimens from Mexico, even though they transplant well and are found by the thousands in some areas. Plants however can still be found for sale here and elsewhere, maybe not cheap but they’re around, and small plants will throw out a decent crown of leaves in a reasonable amount of time.

Dioon edule var angustifolium is reported to be the variety present in NE Mexico. By far the most abundant place I’ve seen them is on the mountainsides west of Villa Mainero. On one slope in particular it is almost the only plant found - an entire mountain of cycads is truly a sight to behold. The scenery in this area is almost surreal, you can easily walk on this finely shredded red shalelike rock up the mountainside and walk amongst the dioons by the thousands, as if you were in some huge botanical exhibit. Though never this abundant elsewhere, they are also common elsewhere in the Sierra Madre and we have seen what look like isolated plants as far north as Monterrey.

Now that’s not to say that Dioon edule is exclusively a plant of the Sierra Madre. There is, in fact, a small population of Dioon edule growing but a few miles from the Gulf of Mexico just east of Soto la Marina. It also appears in Sierra de Tamaulipas and, according to Carl, in the Sierra de San Carlos as well. That coastal site near Soto is interesting, the Dioon only appears in one area and grows amongst a number of other plants usually found in the mountains, specifically Agave striata.

Between Rio Verde and Valles is supposedly found a larger growing form of Dioon edule (var edule) which to me just looks like Dioon edule growing in a wetter environment. RL Frasier and I were able to see this plant in the wild, it does appear more robust than plants seen farther north but this could well be an environmental factor and have little to do with genetics. Where we stopped to photograph it several other cycads were growing, including Ceratozamia aff latifolia and Zamia fischeri, as well as the palms Brahea aff dulcis (a true brancher here!), Chamaedorea radicalis, and Sabal mexicana.

Dioon edule Upper left - east of Soto la Marina Lower left - west of Villa Mainero Above - between Rio Verde and Valles

Dioon edule growing in a large colony west of Villa Mainero

Dioon edule cultivated in Tampico (above), cone at Peckerwood Gardens (left)

Dioon edule has been cultivated for many years in both our area and throughout subtropical parts of the world. It is one of the hardiest cycads to cold - mature specimens can stand temperatures to 15 degrees F without significant leaf burn, though young plants may have some leaf damage, and established plants made it through the freezes of the 1980s in Central Texas. This places it near the top of the list for hardy cycads, though some of the central Chinese Cycas have probably not been tested extensively enough.

The only other cycad known to occur in Tamaulipas is Ceratozamia kuesteriana , a tropical and much rarer cycad in the wild. Currently it is known only from the El Cielo region and the low range of mountains that parallels the road from Cd. Mante to Valles. It is however, fairly popular in cultivation. In spite of its origin from this wet tropical location it seems easy to grow and is plenty hardy for south Texas and even warm protected sites in Central Texas. It is easily distinguished from other ceratozamias and zamias by its dark, long, flat, very narrow leaflets.

Ceratozamia kuesteriana Above - at Zilker Botanical Garden, Austin Left - cone, Peckerwood Gardens

Agaves in Northeastern Mexico Probably the most challenging group of plants to cover for this publication were the agaves, or century plants. Even more than cacti or palms, the agaves are the quintessential Mexican plant. Yes, a few of them slip across the borders into the US or Central America, and there are even more Caribbean species, but the overwhelming majority of the agaves are natives of Mexico and the parts of the US that once belonged to Mexico. And most everyone knows that the national drink of Mexico, tequila, is derived from an agave (A. tequilana), and a number of other species have more practical, sobering uses as well.

But what, then, makes the agaves so tricky to cover? In short, it is their extreme variability - plants in the same species can often appear more different than plants in completely different groups. Impostors run rampant in this troublesome genus. Add to that their propensity to hybridize and you have a great big mess. Oh, and don’t forget that many reproduce asexually by offsets or viviparously and you can have a lot of plants which appear to be a distinct species but are really nothing more than an exaggerated variant of some existing species.

So how are the agaves classified? Well, honestly, the few botanists that have studied them have had to resort to traits that would not be given any attention at all in many genera. Characteristics such as size, striping, or teeth direction are often used to define a species. Imagine an palm botanist trying to get away with something like that!

The difficulties notwithstanding, the genus has been dealt with to a degree of success, mostly by Howard Scott Gentry in the mid-twentieth century. Even today his slightly dated but excellent Agaves of Continental North America stands as the bible for lovers of the genus. There are enough people interested in the genus that it is possible to get some help with them, even when a number of the plants are still tough to assign a species (pure forms almost seem to be the exception rather than the norm). But what is a pain for the botanist is a delight for the gardener, as these differences account for much of the beauty and interest, not too unlike people; many really have a distinct look, a personality to them. Their physical beauty for the true aficionado lies in their rather subtle differences - one plant may have unusually large or colorful teeth, another will have an especially rich banding pattern, while another may have a particularly dramatic bud imprint pattern to it. These wonderful patterns come true to form if you have a plant that happens to form offsets, as most of the species seen in cultivation in South Texas do.

South Texas is a generally excellent place to grow many of the species which come from areas which are not too dry. This area has historically been a haven for agave culture, Gentry even gave the “native” label to several species he saw on his trips to our area, even though they have only naturalized and did not occur in the wild here originally (determining the “original” locations for some of the more popular species is a bit tricky since they have been under cultivation so long, not unlike the date palm). The magnificent naturalized colonies of A. americana on the southern shores of the Laguna Madre near Port Isabel are an excellent example of this. The rarity of heavy frosts in our region allows many agaves to reach flowering size here, including such tender species such as A. desmettiana or A. angustifolia marginata . A well drained soil is all that is needed for most. Plants killed by frost typically regrow new baby pups in the same way they do after the mother plant has flowered and died. For some people, particularly in rural settings, rhino beetle attacks can be a serious problem, but such attacks appear to be localized and not a general problem for their cultivation here. I have had a real problem with the beetle in San Antonio even though I see gorgeous large agaves not more than a few hundred feet of the yard which never seem touched.

Harder to grow are the true desert species, especially those from western Mexico. Many of the wonderful, compact species from the deserts of NW Mexico or the US Southwest may do splendidly here for a while but often rot in an extended wet period. Most of the species from northeastern Mexico, however, are tolerant of our humidity and rains. Surprisingly, a number of high altitude species can handle our hot tropical summer months. That is really amazing to me, considering that some do not occur below 6000 feet in the wild. Agave montana is found above 9000’ above Miquihuana but does not seem to complain in the hot humid summers of Hempstead.

Agaves can broadly be divided into two subgenera: the subgenus Littaea which has a long slender bloom spike similar to a dasylirion, and the subgenus Agave Agave, which has the huge spreading bloom spikes we associate with the genus. As a rule the first group tends to be smaller while the second group is larger and forms imposing landscape specimens which need room to spread and should be placed away from any site in the garden where their sharp leaf ends may cause injury. The following is a rundown of the species known from northeastern Mexico. Only two species, A. lecheguilla and A. scabra (now asperrima), are true natives to South Texas. More species are native to West Texas.

Subgenus Littaea Littaea:

A. bracteosa - this agave can be confused with no other in the genus; indeed, many people don’t even realize it’s an agave. Gentry almost placed this wonderful dwarf species in a separate genus it is so distinct, and from a distance it more resembles a soft leafed tillandsia or a cluster of aloes. It is easy, albeit slow, to grow in sun or light shade in well drained soil and is hardy to Central Texas - I had a small plant survive 6oF in 1989 without significant damage. Worthy of wider cultivation, with its innocent soft leaves and light green coloring, it is the best agave for people who don’t like agaves.

A. celsii and polyacantha - these are among the nicest species in the genus, with their soft supple green graceful leaves. It is surprisingly rare in cultivation in Texas, which is a shame since it appears to do well here in parts of the state which do not usually get severe frost. The difference between A. celsii and polyacantha is subtle at best, in NE Mexico it’s nearly impossible to distinguish them. Gentry described A. celsii as abundantly suckering while A. polyacantha suckers less frequently and sometimes grows epiphytically, mostly on oak trees. I have seen such agaves on the Tula-Ocampo road, and what appears to be A. celsii both east and west of Rio Verde in San Luis Potosi. It is also reported from the El Cielo region. Both of those sites are farther south, but plants in the polyacantha/celsii complex are known from the high country around Dulces Nombres and Puerto Purificacion areas on the Tamaulipas/Nuevo Leon border northwest of Victoria. Some of the plants from this region appear to sucker abundantly while others appear to be single specimens. Whether these are distinct species is questionable at best. It is also reported from the humid north side of the mountains north of Miquihuana. At any rate, these plants seem easy to grow in cultivation as they are fairly tolerant of humidity and some shade and they look splendid with other tropical plants. They should really see more use in South Texas landscapes.

A. lecheguilla complex - this is an extremely abundant and at times extremely confusing group of small agaves.

Agave lecheguilla proper is probably the most abundant agave in existence, it grows by the millions in the Chihuahuan desert (including South and West Texas). Where A. lecheguilla ends and the other species begin gets confusing to say the least. Many are apparent intergrades which adds to the confusion. Gentry did his best to try and sort out the details, though the other species are variable and can backcross in with A. lecheguilla, which makes things even harder. None of the other species are known to be native to Texas, though some have naturalized here. Agave funkiana and lophantha are the two recognized species from extratropical NE Mexico.

Agave bracteosa Above - at Huasteca Canyon, Monterrey Left - cultivated east of San Antonio, TX

Agave celsii/polyacantha Left - at Puerto Purificacion Lower Left - growing in oak trees east of Tula Below - growing with Brahea decumbens, Rio Verde-San Luis Potosi road

A. funkiana - this plant reportedly comes from the Sierra Madre west of Ciudad Victoria and again

farther south. It is very abundant in Central Texas, where it can form large spreading colonies especially on rocky limestone. It is easily seen at the Sunken Gardens in San Antonio and elsewhere. It seems easier to identify in cultivation, in fact, than in the wild. With A. lophantha and A. lecheguilla both occurring in the mountains where A. funkiana grows, and with so many forms and apparent hybrids up in the mountains, it is difficult to separate out something that looks like “true” funkiana. It seems to have characteristics between lecheguilla and lophantha . While not generally the most beautiful of the smaller agaves, plants growing vertically on the rocks, such as at the San Antonio Sunken Gardens, are undeniably dramatic.

A. lophantha - this is probably the most attractive of the lecheguilla relatives. Like A. funkiana , it is common in cultivation in Texas, though it tends to spread less and is usually more attractive since it has a tighter neater crown to it. Plants can be highly variable, though there is a somewhat typical type found in cultivation. According to Gentry it is easily identified by the occasional pair of teeth which come out in opposite directions. Its small usually attractive habit, ability to produce offsets, and wide variation make it a great candidate for horticultural selection. Carl Schoenfeld and John Fairey have selected some particularly nice clones, some of which have no “striping” down the middle and others which have a pleasant bluish cast in their center. There seems to be a larger form just leaving Victoria on the road to Jaumave. A few have been recognized as varieties, such as the following:

A. lophantha coerulescens - “blue lophantha” - this is my personal favorite of the group. Apparently

there are a number of blue forms of lophantha, the one known as coerulescens in cultivation is intensely blue, gets rather large, and suckers abundantly. It is not known from where it originates. There are also some blue forms west of Cd Victoria, on the western edge of the mountain pass as you enter the Jaumave Valley, which also have a distinctly glaucous coloring to them. To me, however, they look more like forms of A. lecheguilla or even A. funkiana, even though they do not appear to sucker much. Some individuals have strongly curved leaves.

Below - Agave bracteosa, San Antonio Botanical Garden

Left - Agave celsii, San Antonio Botanical Garden Above - Agave funkiana Brackenridge Park, San Antonio

Agave victoria-reginae (right) and Agave bracteosa & funkiana type (below) at Huasteca canyon

Agave lophantha cultivars Left - green forms with blue center Above - A. lophantha coerulescens Peckerwood Gardens

Agave lecheguilla/lophantha blue types Right - falcate form NE of Jaumave Below - between Cd. Victoria and Jaumave

Agave lophantha Left - west of Rio Verde, with resemblances to A. xylonacantha Lower Left - typical small form on the pass above Cd. Victoria Below - on the rocks east of Jaumave at Balneario Los Nogales

Left - Agave lophantha, a large form growing west of Cd. Victoria

Probable hybrids of Agave lophantha x protoamericana Lower Left - above Cd. Victoria Lower Right - NE of Aramberri, Nuevo Leon

A. striata - this is a highly variable, very common species in NE Mexico which apparently never crosses the

border into Texas, growing from near Big Bend National Park in Coahuila down through the mountains of Nuevo Leon and Tamaulipas and well south from there. It can even occur near the coast, as it grows with Dioon edule in a low range of hills just west of the coastal plains around La Pesca. Most of the plants are green but it also comes in an attractive blue and red as well. Some plants develop distinctly falcate leaves. At Peckerwood Gardens there are several selected collections, including a dwarf form from the Sierra Chiquita (part of the Sierra de San Carlos) and a large robust form. Around Villa Mainero they take on a grassy appearance (I thought it was a Nolina when I first saw it) and just south on the road to Puerto Purificacion there are exceptionally small, thin leaved individuals which look like tillandsias growing on the rocks. A similar grassy form from Queretaro has been recently named A. tenuifolia , and many of these plants from the Tamaulipas/ Nuevo Leon border region appear very close to this, at least superficially. It is often mislabeled as A. stricta, a species which much resembles A. striata (both in habit AND name).

A. victoria-reginae - the magnificent artichoke agave is one of northeastern Mexico’s horticultural gems,

cultivated and admired throughout the world. The “true” victoria-reginae is a nonsuckering species, coming from the eastern Coahuila/western Nuevo Leon region. It can be easily seen in the dramatic Huasteca canyon just outside Monterrey. It is easily grown in well drained soils in South Texas though sadly most plants are lost after flowering. Some forms, however, will sucker and continue to grow via offsets after the parent plant has bloomed and died. The variant known as A. fernandi-regis is especially attractive with its black tips.

A. victoria-reginae x scabra (asperrima) - according to Gentry, these plants were once common just

outside of Saltillo, forming an impressive hybrid swarm. On a trip RL Frasier and I took there in July of 2003 we failed to find anything other than the dwarf form of A. scabra (now A. asperrima), which does look quite distinct, incidentally, from the “typical” A. scabra seen in South Texas and most of NE Mexico. In December 2003, however, we did in fact locate it after getting a precise location just NE of Ramos Arispe. There the fernandi-regis form crosses with both A. lecheguilla and scabra, the scabra crosses being the more attractive of the two hybrids. The handsome cultivar known as ‘Ruth Bancroft’ is assumed to be the same cross, which arose in cultivation, but it considerably larger than anything seen near Saltillo.

Agave striata Above - a red individual near Saltillo Upper Left - small form from Sierra Chiquita, cultivated at Peckerwood Left - blue form cultivated in Harlingen

Agave striata Above - giant form, Peckerwood Gardens Upper Left - a very dwarf form on the road to Puerto Purificacion Left - coastal green form growing east of Soto la Marina

Agave victoria-reginae - in cultivation near Linares, NL

Above - Agave victoria-reginae (fernandi-regis), Upper Left - hybrid with A. scabra (asperrima) Lower Left - hybrid with A. lecheguilla All growing NE of Saltillo

Subgenus Agave Agave:

A. americana protoamericana - this is the most common large agave of the Sierra Madre in southern

Nuevo Leon and much of Tamaulipas. It is distinguished from the “normal” A. americana by its grey-green to green foliage, which is typically banded. Some well banded individuals can be very handsome. It is abundant in the Sierra Madre, and is easy to see in many of the fairly humid mountain sites in Nuevo Leon and Tamaulipas. It also occurs on the coastal plain around Jimenez and many plants have apparently been taken from the wild in that area for ornamental use along the highway. The plants on the Tamaulipan plains tend to be a darker green and slightly larger than the forms in the mountains farther west. It often hybridizes with A. scabra, especially as you approach drier, more desertlike sites, which can make its identity confusing at times (A. scabra is a Texas native). This can produce some nice clones. On the road to Miquihuana it is possible to see what looks like very silver forms of A. protoamericana or a sort of stable intergrade with A. scabra. If you like your agaves on the grey side then this form is the protoamericana for you. I have also seen apparent hybrids with A. lophantha above Cd Victoria.

A. montana and A. gentryi - these related plants occur in the high Sierra Madre but seem capable of living

in the low hot climate of Central Texas. The two often hybridize and form a sort of complex. A. gentryi is green and has rather long leaves and was once considered to be conspecific with A. macroculmis from farther west.

A. montana is a non-clumping plant, ordinary plants are handsome and the best individuals are gorgeous with their markedly banded teeth and exaggerated bud print patterns. There are a number of intergrades between the two. Unfortunately A. montana does not form offsets, so once a plant is gone it’s gone. This is a shame since it is probably the most beautiful of the larger agaves that I’ve ever seen. John Fairey has also told me that they do not seem to color up in Central Texas as well as plants in the wild.

A. ovatifolia - this remarkable agave was first collected long ago but has only recently been recognized as a

distinct species. It comes from the Sierra de Lampazos between Laredo and Monterrey and appears to be closely related to several species found in West Texas. It has large wide grey leaves and a beautiful flower stalk.

It has been in cultivation for over a decade now in Texas. One plant bloomed in 2003 at the San Antonio Botanical Garden, it seems to like the climate of South-Central Texas very much.

Agave americana protoamericana Left - possible intergrade with A. scabra, Villa Mainero Lower left - in the mountains above Cd Victoria Below - in a roadside planting near Nuevo Padilla

Agave protoamericana types above Cd. Victoria

Agave gentryi x montana types Right - Peckerwood Gardens Below - north of La Ascencion, NL

Above - Agave gentryi type above Miquihuana

Agave gentryi x scabra (?) , east of Aramberri, NL

Agave montana/gentryi types Above - possible hybrid Upper right - spineless form Right - a variegated form All wild plants above Miquihuana

The incomparable Agave montana above Miquihuana

Some especially well-colored individuals of Agave montana growing above Miquihuana

Agave ovatifolia Right - Flowering plant at San Antonio Botanical Gardens Below - Peckerwood Gardens

Two interesting cacti from the Tamaulipan thorn scrub It would have been a monumental project to include all the native endemic cacti from northeastern Mexico. The warm dry Jaumave Valley west of Cd. Victoria is particularly rich in interesting cacti. Many can survive in South Texas, but the best adapted species are those which also naturally occur on the humid coastal plains before the Sierra Madre commences.

There are two species in particular from the low areas of Nuevo Leon down into Tamaulipas which are especially interesting and useful from an ornamental standpoint. One makes a large dramatic columnar tree, the other is a slender rambling vine.

Stenocereus pruinosus - I am not 100% sure as to the correct specific name for this plant, but it is the most common candelabra-type cereus seen in Tamaulipas and parts of Nuevo Leon. It is frequent south of San Fernando, and large plants the size of trees are seen around Ciudad Victoria and again over the Sierra Madre around Jaumave (though other large species such as Myrtillocactus geometrizans also grow in SW Tamps). There are some isolated populations farther north, including some large specimens seen on the new tollway between Monterrey and Reynosa near China. It has been grown for years in the Lower Valley and is slightly tender - plants suffered stem damage in 1989 unless they had a south wall to protect them. I recall seeing some damage in the wild to plants in the San Fernando area. It would be interesting to see if the populations near China are at all hardier. The only other large columnar cactus from the low-elevation thornscrub in Central Tamaulipas is Cephalocereus palmeri. It resembles S. pruinosus but is distinguished by the attractive white hairy growth at the tips of the stems. It is not found as far north as S. pruinosus and therefore I assume it is slightly more tender, it does not make it to the San Fernando or China areas, though I have seen isolated plants just south of Jimenez near the lake. South of Cd. Victoria it becomes much more common.

Selenicereus spinulosus - in striking contrast to the massive columnar stenocereus, this little cactus is a climber and has the habit of a vine, much like a smaller version of the tropical night-blooming cereus. It was once reported as native to the Lower Valley and Bill MacWhorter has said he has seen similar looking plants in some remote locations in the Valley, but officially it’s not a Texas native. Not to worry though, it is plenty abundant south of the border, from the Sierra Madre around Horsetail Falls area down through San Luis Potosi. It also occurs in a number of other fairly humid areas near the coast. Wherever it grows (including in a yard) it gives a very exotic and, yes, even tropical look to the landscape. For this reason alone it deserves much much wider use in South Texas. It is unusually hardy, I have seen thriving plants in San Antonio and have even heard reports of gardeners in milder parts of England being able to grow it. A remarkable plant indeed.

Below - Selenicereus spinulosus in Riviera, Texas

Above - Stenocereus pruinosus near Cd Victoria

Above - Cephalocereus palmeri west of Jimenez Left - Selenicereus spinulosus south of Linares

A pair of vines from the Sierra Madre and adjacent thorn scrub There are two vines which are seen with a fair degree of regularity in Nuevo Leon and Tamaulipas, particularly in the lower mountains of the Sierra Madre. Both have ornamental value, one is already well known in cultivation while the other is extremely rare outside its native habitat.

Mascagnia macroptera - this is the well-known butterfly vine which is commonly offered for sale both here in Texas and other regions. It is popular because of its yellow flowers and interesting light papery fruit which is roughly in the shape of a butterfly (so maybe you have to use your imagination a bit). It grows in areas both humid and dry, its presence in the semiarid Huasteca canyon bears testament to that. It is easily seen in many places in NE Mexico and is virtually taken for granted, both in the mountains and sometimes on the thorn scrub. It will freeze back some in severe cold but has no trouble with the normal winters of Central Texas and is well suited for all of our area.

Marsdenia macrophylla - in stark contrast to the popular butterfly vine, this rambler has gone virtually unnoticed to the horticultural world. This is unfortunate since it appears to be pretty tough and has very large tropical looking foliage. The flowers are small and uninteresting but the large woody speckled fruit does provide some ornament. I first saw it in 1990 in Santa Rosa canyon, and have seen it many times in the mountains and near creeks or wet areas on the coastal plain. A plant I collected in Cruillas in 1994 has been growing on my cyclone fence in Olmito with little care, it really needs no attention here once it’s started.

With the attractive foliage it should make a good substitute for other creepers which do not thrive in South Texas such as English or Boston Ivy. There is a vine which is all too present in Tamaulipas, the rubber vine Cryptostegia. It is also grown in South Texas as an ornamental but does not escape like crazy the way it does in Mexico. It is NOT native to Mexico!

Marsdenia macrophylla Left - near Villa Maneiro Below - at Cruillas

Mascagnia macroptera Above - in Huasteca Canyon Left - near Villa Mainero

Some ornamental flowering shrubs from NE Mexico There are so many interesting shrubs from the plains and mountains of northeastern Mexico that once again it is difficult to know where to start. The following is a brief collection of some of the ones that should have the best ornamental potential for use in South Texas. Of particular interest are some of the bauhinias and a couple of really interesting shrubs which are endemic to the fascinating region in the southwestern corner of Tamaulipas around Palmillas.

Acacia cornigera - this is one of Mexico’s bullhorn acacias, so called because of their large white spines on the stems. These massive spines serve as the home for biting ants which attack anything that tries to eat on the plant. It is common in the southern half of Tamaulipas but is seen sometimes farther north. The northernmost point I’ve seen it is east of San Fernando, right next to the Laguna Madre, where it grows as a low shrub. In the tropics it gets larger, even treelike at times, where it is not in danger of freezing to the ground (it is very resilient). The yellow flowers are nice but the striking white spines really steal the show. The tree Acacia coulteri can also grow as a shrub towards the northern edge of its range near Monterrey, presumably due to frost damage (see Issue Two).

Bauhinia species - there are a good number of bauhinias from NE Mexico, and virtually all of them have

ornamental value. One of them, B. lunaroides, is also a Texas native and not included in this book. The others are only known from Mexico. Here is a quick rundown of the species I am familiar with from the region:

B. divaricata ( B. mexicana) - this plant is so easy to grow in South Texas that it readily naturalizes here,

fooling many into thinking that it’s a native. It almost is, I’ve seen it wild in the Sierra de Tamaulipas and other places in NE Mexico. Again, it naturalizes so easily it can be hard to tell where it is truly native and where it is just volunteering. It is probably the best Mexican bauhinia for humid coastal regions. The top growth is hardy to all but the worst freezes in South Texas, it can be grown farther north with occasional dieback. That is not a bad thing since old plants which get to be the size of trees start to die back and get leggy and unattractive.

Best kept pruned as a shrub in my opinion.

B. bartlettii - this recently described orchid tree is closely related to B. macranthera but is

distinguished by its glossier more pointed leaves and usually more abundant flowering in spring. It is known only from populations in the eastern Sierra de San Carlos near Milagro and just west of Santa Engracia north of Victoria (it is sometimes called the Santa Engracia orchid tree). I did see one large tree of it at the start of the mountain road to Puerto Purificacion, and it struck me as especially handsome with its shiny foliage. Since it comes from lower elevations and seems well adapted to clay soils and at least moderately hard freezes, it should make an excellent candidate for cultivation throughout southern and central Texas. It may well do better than B. macranthera or ramossisima in the more humid areas of far South Texas.

B. coulteri - this is generally a small scandent shrub which grows from southwestern Tamaulipas into San Luis Potosi and beyond. It is especially abundant in the areas where Brahea decumbens and Pithecellobium elastichophyllum is found on the San Luis Potosi-Rio Verde road, but it has been reported near Miquihuana as well. It seems to appreciate some shade. The flowers are pinkish to white and it blooms sporadically throughout the warm months. Successfully growing at Peckerwood Gardens in a shady location, I don’t know how it would stand the water and subtropical conditions of South Texas.

B. macranthera - a nice little orchid tree or shrub from the Sierra Madre of Nuevo Leon and Tamaulipas, it has small but nonetheless attractive purple spring flowers. It is known in Texas horticulture and a survived 6oF in 1989 with virtually no damage. Like B. lunaroides, it may be better suited to inland areas than the near-tropical conditions of coastal southern Texas.

B. ramossisima - this generally replaces B. lunaroides to the south, occurring from Tamaulipas

and areas westward. The flowers are much like a smaller version of B. macranthera but are typically a darker more intense color. The leaves are also smaller, more like B. lunaroides. It is a variable species and a nice form is growing at the San Antonio Botanical Garden. It probably prefers conditions similar to B. lunaroides .

Acacia cornigera in Harlingen

Bauhinia bartlettii Peckerwood Gardens

Bauhinia lunaroides pink Mexican form, Peckerwood

Bauhinia macranthera near San Antonio

Bauhinia ramosissima San Antonio Botanical Gardens

Bauhinia coulteri Above - Rio Verde to San Luis Potosi road Left - Bloom at Peckerwood Gardens

Bauhinia divaricata (=B. mexicana) cultivated in the Lower Rio Grande Valley

Flourensia laurifolia - this shrubby sunflower relative is extremely common from central Tamaulipas

and southwards. Unfortunately, it seems to go completely unnoticed as an ornamental, even though it has nice thick leaves and attractive clusters of yellow flowers in fall. It is easily seen both on the plains and in the mountains around Victoria, Jaumave and elsewhere. I don’t think it would be difficult to grow, and it really has potential for South Texas.

Mimosa martindelcampoi - this is a wonderful gem from the mountains of SW Tamaulipas. The foliage is completely unlike any other mimosa, the leaflets are large and round and you would not even know the plant is a legume at first glance. Add that to the beautiful pink flowers and you have a real winner. It has been tried as far north as Central Texas, where it appears to be a rapid grower. It is easiest to see south of Palmillas, though you can catch it on the Victoria-Jaumave mountain road as you descend into the Jaumave Valley.

Morkillia acuminata - another treasure from SW Tamaulipas, this outstanding shrub has unfortunately

never caught on in cultivation. That’s a shame, since the combination of the silky gray foliage and large purple flowers is wonderful. The flowers look something like a hibiscus though the plant is actually in the zygophyll family, like our native guayacan. Nobody seems to know the hardiness of the shrub, but since it looks to be multi-trunked it should be at least root-hardy. Given its native range it probably demands dry, well drained conditions. It is most frequent south and east of Jaumave, especially on the road to Balneario Los Nogales east of town. Well worth a try, particularly in warm western areas of South Texas.

Tabernaemontana alba - this is mostly a tropical shrub which grows in the more humid areas of

Tamaulipas as far north as the Llera area in the west and the Soto la Marina area in the east. Its main attraction is the large tropical looking foliage. The small flowers are no match for the Indian carnation (another Tabernaemontana), but they are every bit as fragrant. It has been grown at the old Link Nursery in Weslaco for many years, apparently freezing to the ground in extreme cold but recovering every time.

Flourensia laurifolia near Ciudad Victoria

Mimosa martindelcampoi Above - San Antonio Zoo Right - south of Palmillas

Morkillia acuminata near Jaumave

Tabernaemontana alba Above - west of Valles Left - in Olmito, Texas