The diversity of plant species is astonishing. Even plants in familiar genera can surprise us. 

Take the Quercus genus, which is that of oaks. I was recently introduced to the Japanese live oak or bamboo oak (Quercus myrsinifolia). Its pendant, lanceolate leaves look like they belong on a willow tree or, as its name indicates, on bamboo. I made this oak’s acquaintance courtesy of “Plants for the Winter Garden” (Timber Press, 2024), by Warren Leach. The author says of this oak: “It merits a gardener’s lust,” a superlative testimonial if there ever was one. Although this book was written for those living in cold winter climates, many of the plants — including bamboo oak — are suitable for growing in warm winter climates such as ours, too. 

Bamboo oak is mentioned in a chapter on evergreen trees and shrubs. It’s a live oak which means that it’s evergreen, unlike deciduous oaks that are mostly native to cold climates and do not grow well in our part of the world. Mahonias, some of which are native to California, are highlighted. Oregon grape (Mahonia aquifolium), native to Northern California, has prickly pointed foliage that turns red this time of year even as its blueish purple fruit, which follows golden flowers, still hangs from the shrub. 

Nevin’s barberry (Mahonia/Berberis nevinii), an endangered species, is the most attractive member of the genus not only to people, but to birds. That’s due to its scads of small red fruit, in addition to brilliant flowers that blanket the blanket each spring, complemented by blue-grey to green foliage. This chapter extols leatherleaf mahonia (Mahonia bealei) in particular. I have never seen this plant up close but have a craving to ogle it as its compound pinnate leaves are more than a foot in length with five-inch long leaflets. 

I also learned about a silvery-blue variety of giant sequoia (Sequoiadendron giganteum var. Hazel Smith). A solo sequoia seedling that had been transported from Oregon to New Jersey survived the Jersey winter and was named after the proprietress of the nursery where it was nurtured. This is a fast-growing sequoia that is hardy down to 20 degrees below zero. Speaking of silvery-blue, let’s not forget the Arizona cypress (Cupressus arizonica), whose form is a perfectly symmetrical cone and whose bark is deep cinnamon in color. And then there is the weeping blue Atlas cedar (Cedrus atlantica cv. glauca pendula). Left to its own devices, this species will trail along the ground. Due to this natural growth habit, it is trained so that a single trunk develops from which an arching canopy grows, eventually reaching a height of twenty with an equal spread.

This book also introduced me to the concept of “marcescent foliage.” Marcescence refers to the phenomenon whereby certain deciduous species retain their dead leaves through the winter. In Southern California, the European beech (Fagus sylvatica) is the classic tree on which to observe a display of dead leaves that stay in place. It is especially attractive on varieties with copper or purple foliage. While you might be legitimately concerned about planting beech trees since they may sky to 60 feet in height, you can also plant the Purpurea Pendula or weeping copper beech that grows only 10 feet tall and wide.

We think of Yucca as a genus of plants native to the desert yet there is one species indigenous to the east coast from Maryland to Florida. This plant is Adam’s needle (Yucca filamentosa) and Bright Edge, a cultivar with golden margins around its spear-shaped leaves, is especially appreciated under dark winter skies. This leads me to recommend a number of succulents that provide color not only in winter, but throughout the year. The paddle plant (Kalanchoe lucia) is at the top of the list with leaves that are green, blue, red, and gold. Next would be Aeonium “Sunburst’ with yellow, green, and pink foliage. Finally, the entire genus of Echeveria includes plants in every color of the rainbow and then some. These colorful succulents are useful not only for adding permanent color to the garden bed but, due to their slow growth and minimal water needs, make outstanding selections for a container garden.

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A reader wondered about leaves on an orange tree that were contorted and marked with squiggly lines. This condition is brought on by leafminers, which are larvae (of a moth species) that tunnel through foliage. The good news is that you do not have to be too concerned about this pest as the University of California integrated pest management website (ipm.ucanr.edu) assures us with these words: “The best course of action is to leave it alone and let the natural enemies of the citrus leafminer feed on and parasitize the larvae in the mines, rather than trying to control this pest with insecticides.”

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A recent discussion of bulbs in this column prompted Carol Forsythe to send the following email: “I planted a Scilla peruviana bulb and waited so long for it to bloom, I forgot about it. Imagine my surprise and utter delight when it FINALLY bloomed, 15 years after planting, this last March.” Her bulb is a species of squill that is native to the eastern Mediterranean and North Africa. Thus, its climatic requirements match our own. Forsythe’s squill displays a flower that consists of dozens of starry mauve florets with deep blue centers and golden anthers. Squills bloom at various times of the year, depending on the species. In Israel, for example, sea squill (Urginea maritima) blooms in the fall, an event which heralds the approach of the rainy season. This plant is associated with a tradition that Joshua (the one in the Bible, not me) used it to mark the borders of the land of Israel.

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After asking if anyone knew of a local source for the native Humboldt lily, I was informed by Paul Cruse that it may be found at Tree of Life Nursery (Californianativeplants.com) in San Juan Capistrano.

California native of the week: Pacific blackberry (Rubus ursinus) is found growing all along the California coast and in selected inland areas as well. It is a sprawling species that serves well as a ground cover. Its fruit is sweet but you will need to wear an armored pair of gloves when picking due to its hooked thorns. Pacific blackberry will attract wildlife of every description including bears, from which its species name (ursinus means bear in Latin) is derived. While this plant is drought tolerant once established, it produces more fruit and of a larger size when it is regularly watered. Like all blackberries it can grow in sun or some shade, but will require more frequent irrigation as its sun exposure is increased. A tea can be made from its leaves and it was a closely related blackberry species whose foliage was used for this purpose by colonialists after their boycott of British tea. You will need to monitor the spread of Pacific blackberry since its arching canes will root wherever they touch the ground. For this reason, it is a fitting edible option for erosion control on slopes. You can find Pacific blackberry at Tree of Life Nursery (californianativeplants.com)

If you grow a perennial plant which looks its best in fall or winter and you would like to share your experience here, please send an email to [email protected] Your questions and comments, as well as garden problems or their solutions are always welcome.