crape myrtle

CRAPE MYRTLE: Lagerstroemia sp., crepe myrtle, baegilhong 백일홍 (Korean), zǐwēi 紫薇 (Chinese)

ORIGIN: parts of Asia and Oceania

MATURE HEIGHT AND WIDTH: highly variable; size depends on species; popular Lagerstroemia fauriei x indica cultivars range from 8 to 30 ft. high and 8 to 30 ft. wide depending on the cultivar

GARDENING NOTES: relatively well-behaved near sidewalks; cultivars include trees with white, lilac, and blood red blossoms; although not native, it provides ecosystem services in novel urban landscapes as a food source for native American Goldfinches and House Finches, at least in parts of the United States; leaves of Lagerstroemia indica in particular turn festive colors in the fall; prefers sunny exposures but can grow in partial shade.

A DESERT DWELLER, Encelia farinosa has a wide range covering dry parts of Southern California, Mexico, and the southwestern USA. Driving through the desert at night, x-ray brittlebush shrubs flicker by like stop-motion animation. During the day, their white stems resemble huge lichens. The Spanish name “incienso” refers to the plants’ sap, which is used as an incense.

Novel Landscapes For A Novel Future

“Within the lifetime of children living today,” write scientists Matthew Fitzpatrick and Robert Dunn in the journal Nature Communications, “the climate of many regions is projected to change from the familiar to conditions unlike those experienced in the same place by their parents, grandparents, or perhaps any generation in millenia.”

Of course, we are already experiencing a different climate than previous generations. And under current carbon accumulation rates, in 60 years, summer temperatures in the

Los Angeles region are expected to be nearly 6F degrees warmer on average. This means that the current North American climate we would most resemble in 2080 is Cabo San Lucas, Mexico.

The match is not perfect: Cabo San Lucas does not have Los Angeles’ wet winters and dry summers. But droughts are expected to become more frequent in Southern California, soil moisture will evaporate more quickly, and most of our water will come in fewer, larger, storms.

Whatever happens over the next 6 decades, Southern California’s ecosystems are certain to be under extreme stress. It is likely that some plants will cease to exist in parts of their current range. As a public garden, we are planning for this future landscape by growing species, such as brittlebush, that thrive in warmer, drier regions of the California Floristic Province.

BRITTLEBUSH: Encelia farinosa, incienso (Spanish)

ORIGIN: California Floristic Province including Baja California and desert regions of the southwestern USA

MATURE HEIGHT AND WIDTH: 1-5 ft. high and 4 ft. wide

GARDENING NOTES: yellow daisy-like flowers appear in the spring; very low water needs, can survive on rainfall once established in their “natural” range, although as discussed below, the changing climate will change the contours of this range; looks best in full sun away from the coast with limited water in quick-draining rocky or sandy soil; loses foliage in drought.

The Special Relationship

Scrub jays, squirrels, and other animals are an essential part of the regeneration and proliferation of coast live oaks. In fact, the mutually beneficial relationship between corvids, like scrub jays, and oaks is literally world-changing, as it is one of the main engines of grove creation worldwide. A study conducted near Carmel along the California coast found that individual jays cached — that is, stored for future consumption — an average of 5,000 acorns in a year! Each of these acorns was hammered in the ground, one at a time, repeated over-and-over-and-over-again.

With an impressive recall ability, scrub jays return to around 95% of their cached acorns. The 5% of acorns that they don’t recover often germinate in the ground, safe from herbivores. Some of these acorns grow into new oaks outside their mother groves and make forests.

WHY ARE ACORNS THE PERFECT FOOD?

Some scientists theorize that the high carbohydrate content of acorns functions to increase animal hoarding. Carbohydrate-rich acorns quickly sate the hunger of animal foragers like jays. Once full, many foragers will collect and store additional acorns in the ground, increasing their chances of germination. The thick shells of acorns are thought to reinforce this behavior: the longer it takes to gnaw or peck through a shell, the more vulnerable the animal is to predators. Hence, rather than eat an acorn on the spot with all of the attendant risk, hoarders are more likely to store their meals for later.

Philosopher Oak

California’s live oaks live so long and are so prominent in the landscape that they take on mythological significance. The dramatically-named “Oak of the Golden Dream” near Santa Clarita is associated with the first documented non-Indigenous discovery of gold in California. The “Lang Oak” in Encino was a famous 1,000 year old tree with a 24 ft. circumference trunk. Orange Grove Blvd, west of Arlington Garden, is out of alignment with other major north-south streets in Pasadena. The street was built to connect two large, well-known oaks, one of which stood near the garden at the intersection at California Blvd. and Orange Grove Blvd. Pasadena residents loved the oak so much that they raised funds to build a long circular bench around it in 1884. A local newspaper optimistically predicted, “We presume this spot will someday be like unto the ancient forum at Rome, where the philosophers and orators of Pasadena may come to discuss the questions of the day.” Unfortunately, this admiration for the tree is what killed it. Construction of the road around the oak’s understory was likely the cause of its demise in 1911.

western sycamore cont.

measured 20 feet in circumference. Its canopy stretched 200 feet across. A drawing of the tree by the artist Edward Vischer in the 1800s shows a smooth trunk terminating abruptly in a bundle of muscular arms resembling a giant squid.

The tree was a sacred site to the native people of Los Angeles County — the Tongva, Kizh, or Gabrieleño — who gathered under its branches and used the surrounding area as a burial site. In the 1830s, a French immigrant constructed a winery near the tree — did he know that people were buried there? — and over the decades, it expanded until the tree was cut back and fenced in on three sides. This was not a healthy habitat for the tree, and it succumbed to industry, convenience, and disregard for the older world that was becoming Los Angeles.

In 2019, the City of Los Angeles installed a historical marker for the tree in an unwalked strip of pavement between a strip club and the freeway. Invasive weeds grow along one side and razor wire on the other, but it is near the original site. Chief Ernie P. Tautimez-Salas, who wrote the inscription, ends it with this promise: “while its physical presence is gone, the oral history handed down through the generations has kept its beauty and story alive in the Kizh people.”

hummingbird sage cont.

Although there is disagreement about the exact nature of the relationship, oaks have an important connection with “mycorrhizae” — subterranean fungi that associate with plant roots. Many scientists believe these fungi coat or infiltrate the roots of oaks and surrounding plants, providing them with water and hard-to-access nutrients from the soil. In return, partner plants share (or the fungi take) energy in the form of sugars and other essential elements of life.