The California Lavateras and Their Hybrids

In the world of mallows, the greatest hybridization effort—and most significant achievement—has involved the several compatible species in the tropical hibiscus group (Hibiscus rosa-sinensis). This may be due to the fact that these hibiscus are easily grown in containers and, therefore, can be treated as houseplants all over the world. Hybridizers have also worked with other species, such as rose-of-Sharon (H. syriacus) and several of the European species in the genera Lavatera, Malva, and Alcea (hollyhock), but these efforts have been limited, perhaps due to the size of the plants involved and their fairly limited color variation and range of growing areas. Until recently, no one has worked with California’s three native mallows in the genus Lavatera.

The California species of Lavatera have a limited and easily defined natural range. They are found on the Channel Islands off the coast of Southern California, and on the Mexican islands of Guadeloupe and San Benito, off the coast of Baja California; the latter islands are considered to be a part of the California floristic province. There are now thought to be three species of native mallow found on these islands: Lavatera assurgentiflora, L. venosa, and L. occidentalis.

The California Trio

Lavatera assurgentiflora is the most northerly species, found on the islands of Santa Cruz, San Miguel, and Anacapa, with subspecies glabra found on Santa Catalina and San Clemente. It is also considered to be naturalized in the Santa Monica Mountains on the mainland of Southern California. (One cannot help but wonder how they survive the depredations of mainland deer, which love most of the mallows.) Although this species comes from the southern, and milder, part of California, I have found it to be quite cold hardy in my Danville garden (Sunset zone 14, USDA zone 9), surviving temperatures into the high teens. It is also grown in parts of England.

Lavatera assurgentiflora is variable in size, usually averaging between six and eight feet in height but sometimes reaching higher. The trunk can be as much as twelve inches in diameter at the base, with branching beginning low to the ground. The flower color is a deep cerise, and flowering occurs nearly year round. Flower size is dependent upon the weather: in the winter, they can be two inches wide, whereas in the summer, they remain closer to one inch wide.

This species survives the hot, dry summer conditions experienced in the interior of California by partially defoliating to reduce moisture loss; in my garden, it does well with summer irrigation, undoubtedly adapted to the moisture provided by the dependable summer fog of their island habitat.

Lavatera venosa occupies the southern-most part of the range, coming from the island of San Benito; it has also become naturalized on the Baja peninsula in the area of Vizcaino. This species also seems to handle cold weather, having survived temperatures in the high teens in my garden. The flowers are larger than on L. assurgentiflora, are soft purple with a pink edging, and have deep purple veins. My plant is more prostrate than L. assurgentiflora (now about three feet high by five feet wide), although it behaves similarly in every other way.

Lavatera occidentalis is the most mysterious of the three. It is found only on the island of Guadeloupe, off the coast of Baja and is said to have deep purple flowers. I have three seedlings that have not yet flowered; I am hesitant to plant them out as this species is said to be the most frost-tender of the three. Its leaves are more palmate than the other two.

California Hybrids

Ed Mercurio, a botanist and plant lover who gardens in Salinas, California, has been playing with these three island species of Lavatera in his garden for a number of years. He began hybridizing L. assurgentiflora and L venosa, but felt his efforts were producing only uninteresting blends of these two species.

While exploring the Santa Barbara Botanical Garden, Ed found an unusual seedling with bluish purple flowers. He was given permission to take a cutting from this plant, since all the seedlings in that area of the garden were hybrids and would likely be eliminated. He took only one cutting, which rooted easily and joined the two species and earlier hybrids in his garden. From that time, primarily through open pollination (ie, the bees did the work) he has produced seedlings with distinctly different—and much more interesting—color variations in the flowers. He believes that the original blue color came from Lavatera occidentalis. He also believes that this species is the most tender of three lavateras; during our big freeze in 1990, he lost all of the bluer hybrids. Seedlings of those lost, however, continue to produce bluish flowers.

Ed now has a forest of hybrid California mallows in his backyard in the middle of a suburban neighborhood. Because he has little time to track the parentage of these plants, he merely lets them be pollinated in a random pattern by the local bees. He has recently introduced into the nursery trade a few selections from among his hybrids, including ‘Bold Stripes’, which is white with purple stripes, and ‘Black Heart’, purple with a near black center. Several of his hybrid selections can now be seen at Rancho Santa Ana Botanic Garden in Claremont, California.

California Mallow Resource Guide

The three species of Lavatera native to the islands of California and adjacent Baja California can be seen at the following gardens:

Santa Barbara Botanic Garden
1212 Mission Canyon Road
Santa Barbara, CA 93105

Rancho Santa Ana Botanical Garden
1500 North College Avenue
Claremont, CA 91711

For more information about the mallows of the California and Mexican islands, consult the website of Stewart Robert Hinsley at www.meden.demon.co.uk/Lavatera/californian and search for The Californian Lavateras.

Ed Mercurio is happy to welcome visitors who wish to see the collection in his garden. Contact him at mercurio@jafar.hartnell.cc.ca.us.

Seeds and Plants
San Marcos Growers
125 South San Marcos Road
Santa Barbara, CA 93111
www.smgrowers.com

Seed collected from hybrids in Ed Mercurio’s garden is available through the author. Contact her at yankerhans@hotmail.com.