Growing Cajun Prairie Milkweeds Malcolm F. Vidrine & Gail Q. Vidrine Cajun Prairie Gardens
Presentation Outline • A bit of history • The prairie garden through the year • Cajun Prairie milkweeds (Asclepias) • Growing milkweeds • Monarchs in dire straits • Biodiversity is the key
A Bit of History â€˘â€ˆ The Great Southwestern Louisiana Prairie aka The Cajun Prairie covered 2.5 million acres in 1700. A vast array of grasses and wildflowers dissected by bayous lined by gallery forests. The French divided the land along the bayous into long lots. The open prairie was later divided into square lots by the Americans.
Remnant prairies in the Cajun Prairie • Charles Allen and Malcolm Vidrine visited these remnant prairies in the 1980s and 1990s—many routinely! • Three major named prairies with good remnants were visited: Mermentau, Calcasieu and Plaquemine. Other prairies had very small or poor quality remnants.
The prairie garden through the year The Cajun Prairie Gardens
Landscaping with Prairie Plants Habitat restoration/recreation Natural landscaping and Wildscaping Wildflower gardening Butterfly gardening Pollinator or wildlife gardening Microprairies (minuature prairie gardens) Biodiversity gardening
Multiple Use Gardening • Landscaping with natives for beauty • Landscaping for ease and frugality • Outdoor classrooms for teaching ecology • Butterfly/pollinator/wildlife gardening • Food and medicinal native gardens (edibles, mints, varied herbs, etc.) • Historical gardens (natural ecosystems)
The Cajun Prairie Gardens
2013—17th Year • The following slides show the gardens in the 17th year of development
Cajun Prairie Milkweeds • Asclepias tuberosa Butterflyweed • A. lanceolata Few-flowered milkweed • A. perennis Aquatic milkweed • A. vericillata Whorled milkweed • A. viridis Green antelopehorn milkweed
Cajun Prairie Milkweeds (cont’d) • Asclepias obovata Pineland milkweed • A. longifolia Longleaf milkweed • A. viridiflora Green Comet milkweed • A. variegata White milkweed • A. curassavica Tropical milkweed (exotic)
Growing milkweeds • Seed collection • Seed storage • Cold moist stratification • Planting • Transplanting • Propagation from roots and stems • Pests and diseases
Seed collecting • Follicles are produced when the flowers are pollinated. • Each follicle can contain a dozen to a hundred seeds depending on the species • Seed should be stripped from the follicle when the follicle cracks open under gentle pressure (leave the silk parachutes behind).
Seed Storage â€˘â€ˆ Store seed in a dry, cool place (even your living room in a dry container is good)
Cold Moist Stratification (see www.butterflyencounters.com)
• When you are 6 weeks away from planting day, it is time to begin CMS. • Place seed in damp sand in a ziplock bag in the refrigerator. • After 6 weeks, remove the seed from the sand by floating them in water. • Plant the seed immediately in good potting soil. Germination should be uniform (simultaneous) and at a high rate in 1 week.
Planting and Transplanting • Whereas the seed readily germinate with CMS, moving the seedlings is problematic. • Moving the seedling to successively larger containers requires transplanting—an event that is very stressful to plants.
Asclepias spp. seedlings 051212
Propagation from Roots and Stems • Root cuttings and stem cuttings in springtime are generally successful if done before the plant begins to bloom. • Much care and patience are needed—these plants are susceptible to a variety of deprivations including insufficient water and a variety of diseases.
Pests • Milkweeds are attended by a great variety of insects— apparently most of these prefer milkweeds. • Oleander aphids are the pesky little yellow-orange critters that abound on milkweeds. Their presence indicates the absence of systemic insecticides. They can be washed away but usually should be ignored on healthy plants. • Stinkbugs of several varieties do little damage to the plant, but they suck follicles dry. These must be managed for seed production. This can be done with 2 fingers. • Milkweed beetles can be easily removed with 2 fingers.
Pests/Visitors • At least one species of stinging moth larvae occurs on milkweeds—these voracious eaters provided a whalop of a sting. • Many wasps and bees pollinate milkweed flowers—the wasps also remove insects for their young—unfortunately they remove many Monarch larvae. • Many other insects commonly visit the milkweeds for nectar and food, thus providing an excellent garden for insects/pollinators, including hummingbirds.
Diseases and other considerations • Unfortunately, several varieties of rot (fungal or bacterial) can reduce the root system to mush. The plants appear to lose rigor and wilt when attacked. These plants should be discarded immediately. • Most native milkweeds can tolerate ‘wet feet.’ Some species apparently enjoy it, others do not. Aquatic milkweed and Few-flowered milkweed tolerate ‘wet feet.’ Butterflyweed and Green antelopehorn do not; however, the Cajun Prairie Butterflyweed tolerates ‘wet feet’ far better than any other variety of Butterflyweed. Whorled milkweed appears to have no preference and grows well with or without ‘wet feet.’
Milkweeds are difficult to grow • Unlike the weedy species found in the northern prairies, our coastal prairie species are difficult to grow and establish for the long haul. • Collect seeds that are mature. • Fully expect to lose many plants: • a. when moving them from one place to another • b. and in spite of doing everything you would normally do for any other plant. • Plants may not bloom the first year.
My suggestions • Grow as many species as possible—one or 2 may be better suited for your planting site • Do not plant seeds out of doors except in containers after CMS (cold moist stratification), and even then it is best to plant them in a large container. • Move them during the dormant season or just as they are breaking dormancy after a year’s growth in containers .
Monarchs in Dire Straits • Monarchs are the symbolic insect of the prairies and of North America. • Monarchs are the most recognized of all insects. • Monarch (Danaus plexippus) numbers are crashing to a level that potentially threatens the continuation of the great annual migration across North America and ultimately the survival of the species.
Everything eats Monarchs • Monarchs are prey to a large number of insects, especially parasitic wasps, wasps, preying mantids, etc. • Monarchs are prey to spiders. • Even birds taste Monarchs, even though they learn quickly not to prey upon them. • And Monarch larvae occasionally eat Monarch eggs.
Biodiversity is the Key • The key to not only protecting butterflies and plants is biodiversity. • Whether it is water, soil or air, the key to keeping it clean and biologically productive is maintaining biodiversity. • Our actions are eliminating biodiversity at a rapid rate—only our actions can change this.
Non-natives • Tropical (aka Mexican, Brazilian, Ornamental) milkweed is the mainstay of the horticultural trade and the poster plant for saving the Monarchs. • Two apparent setbacks: • 1. Wrong chemical signals for Monarchs • 2. Overwintering in warmer climates where it hosts OE spores.
OE • McLaughlin, Roy E. and J. Myers. 1970. Ophryocystis elektroscirrha sp.n., a neogregarine pathogen of the monarch butterfly, Danaus plexippus (L.), and the Florida queen butterfly, Danaus gilippus berenice Cramer. Journal of Protozoology 17 (1970): 300-305.
• A protozoan parasite of Monarch and Queens whose spores can be ingested by larvae. • Pathology and epidemiology of OE as yet unclear, but concerns have arisen.
Solution = Biodiversity • When Monarchs are given options among different species of milkweeds, they appear to chose those that lack spores and provide appropriate signals, usually native species. • We need to provide a selection of species for oviposition by Monarchs—not just Tropical milkweed—preferably natives.
Milkweeds and Monarchs • It is now apparent that both milkweeds and Monarchs are in dire straits. • Both are succumbing to the accelerating loss of habitat (habitat = milkweeds). • Apparent causes: exponential increase in use of biocides; urban development; clean farming; loss of Mexican forests.
Monarchs need plants • During Spring migration, Monarchs need milkweed for their oviposition and larval development; they also need nectar plants for adult nutrition, • During Autumn mirgration, they need nectar plants for adult nutrition. Peak migration at our latitude is late October into early November.
What can we do? • Plant milkweeds • Plant nectar plants • Reduce massive use of biocides; find alternatives. • Get the word out • Every town, business, school, and home should have a small plot of milkweeds, where biocides are not used!
Caution • Neonics = neonicotinoid insecticides • Some nurseries treat their seeds with systemic insecticides which then transfer to all parts of the plant. • This treatment greatly reduces the impact of insects upon the plants; however, it deleteriously affects Monarchs and other butterflies.
Caveat #1 • In Louisiana and Texas, we can mow these milkweeds during late July to early August for an additional bloom season. • The Monarchs are gone and the initial burst of blooms and seeds are done by the beginning of July. • Monarchs return in October and may or may not lay eggs, but they will surely feed on nectar for travel to their winter grounds in Mexico.
Caveat #2 • In southern Texas, populations of Monarchs are now considered residents—they spend the summer and possibly even the winter in south Texas. • This brings forth a number of questions, including not only what milkweeds, nectar plants and shelter might be provided but also what management techniques are needed to protect these populations. • These populations need study!
Federal Protection • A movement is afoot to obtain federal protection, labeling of Monarchs as either endangered or threatened. • A nationwide debate has developed, e.g., MonarchWatch’s spokesman Chip Taylor has penned a strong essay opposing this move and favoring a public response in planting literally thousands of acres of milkweeds—one backyard at a time.
Closing notes • A manicured lawn provides nothing for Monarchs nor for much else. • Only 2 Monarchs have visited our gardens so far this April—we really hope that this is because you have planted thousands of milkweeds thereby delaying their arrival and hopefully promoting a tremendous increase in the number of visitors.
Now Blooming @ Cajun Prairie Gardens
Questions Thanks for your invitation!
Lecture delivered on 04/16/2015