Carolina jasmine (Gelsemium sempervirens)
The late rain we received should give us that many more flowers this spring. The salt that accumulates in our soil, which is a residue of minerals carried in summer irrigation water, is leached down and past the root zone as the result of saturating rains. Soil salt inhibits flowering so its depletion following rain is a favorable development.
Many of the first flowers of spring are golden yellow. Research has revealed that the first blooming plants may well have had sun-colored flowers, as if to acknowledge the light-giving source that makes vegetative life possible on Earth. Plants with yellow flowers are more likely to originate in warm climates than in cool ones.
The floral curtain that encompasses our city is embroidered each February with the yellow trumpets of Carolina jasmine (Gelsemium sempervirens). This fragrant vining plant is native to the East and Southeast, from Virginia to Florida to Texas, and may be found growing wild in Guatemala as well. It is both poisonous and medicinal. Its curative powers were discovered 150 years ago when a Mississippi farmer who had taken ill consumed its root by accident, thinking it was another medicinal plant. Ingestion of the Gelsemium root only made him sicker, to the point where he was given up for dead. When he finally recovered, his cure was properly attributed to the plant that nearly killed him, and a new drug therapy was at hand. Used in correct dosages, Gelsemium alkaloids became famous for their analgesic effects.
Carolina jasmine is available now in most nurseries. Planted from 1-gallon containers, it will cover a 6-foot fence in a few years. Once established, it requires only occasional summer irrigation. Italian jasmine (Jasminum humile) grows into an 8-foot shrub with butter-yellow flowers that may be seen at any time of the year, including now.
One of the most spectacular yellow-blooming March flowers is the velvet groundsel or California geranium (Senecio petasitis). In truth, it is a member of the daisy family, though, when not in bloom, its huge geranium-like leaves easily create a mistaken horticultural impression. When in flower, as it is now, dozens of 1-inch daisies form enormous clusters, rising above the leaves.
Leguminous trees and shrubs that are native to dry climates are either blooming now or will be soon; nearly all of them have yellow flowers. The obscure yet distinctive canary bird bush (Crotalaria agatiflora) is a drought-tolerant shrub that deserves wider recognition. It has an open, arching growth habit and blooms on and off all year long. More common legumes include the acacias, with their small spherical sulphur flower puffs, as well as Cassia artemisioides, its finely cut leaves offering considerable garden interest after flowering has passed.
One plant that is a source of pride to any California gardener is Dendromecon rigida, the bush poppy. Possessed of clear yellow flowers that will bloom through the summer, this shrub is at the top of the list of those who admire California natives. No other plant that grows in our gardens produces this sort of silky yellow flower for so many months, to say nothing of the bush poppy’s complement of memorable gray green leaves.
Lovers of succulents can ogle at least three species with yellow flowers this month: Sedum confusum, the lushest succulent ground cover; Lampranthus aurantiacus “Sunman,” a bright yellow flowering ice plant and Euphorbia rigida, an architectonic delight with blue-gray leaf spears, lemon yellow bracts and an uncanny self-sowing capacity.
Bulbinella nutans produces yellow torch-like flowers at this time of year. It naturalizes in any sort of soil, from damp to dry, through vegetative propagation of its bulbs and by self-sowing of its seeds. Bulbinella completely disappears during dry summer months, which are its period of dormancy, but reliably reappears with the onset of cool weather in the fall. A slope covered with glowing Bulbinella torches is a breathtaking sight and ogling it is the only maintenance required. Make sure you plant Bulbinella nutans, available in yellow or orange, since there are other Bulbinella species found in the nursery trade, yet none as hypnotically delightful as this one.
Most gardeners in the Valley are familiar with the Euryops pectinatus daisy, a tough flowering shrub that seems to be nearly always in bloom with golden daisies that are complemented by finely cut deep green or gray foliage. Euryops virgineus is another garden worthy shrub. Its flowers are much smaller yet even more abundant than those of its cousin and and its leaves are narrower and more delicate. It also grows taller, eventually reaching six feet in height.
