Conejo Valley Botanic Garden is on a magic mountain
The Conejo Valley Botanic Garden, a hillside and hilltop horticultural haven, is a community asset highly worth a visit. Rising above the surrounding city of Thousand Oaks, this modestsized magic mountain has soil that has never been amended, and the plants that thrive there have never been fertilized.
Three factors have contributed to the plants’ well-being. First, they are constantly mulched with tree trimmers’ wood chips. Second, the sloping terrain for the hillside plants and the granitic soil for the hilltop plants ensure that water drains completely away from roots — a critical factor, since the least bit of standing water would be fatal to many of the dry climate species on display. Third, the devotion of volunteers to maintenance of the collections, which include plants from the five Mediterranean climate zones around the globe — California, Chile, the Mediterranean Basin, South Africa and Australia — as well as a butterfly garden, a tranquility garden, a rare fruit orchard, a butterfly garden, an herb garden, a salvia garden and a fern.
The botanic garden is open from 8 a.m.-6:45 p.m. daily at 400 W. Gainsborough Road. The Kids’ Adventure Garden is open from 11 a.m.-3 p.m. Sundays. A plant sale is held from 9 a.m.-noon Wednesdays. Admission is free. Dogs on leashes are allowed. Masks are required.
Speaking of the power of mulch, 10 years ago when I visited this botanic garden, there was a vast expanse of weedy black mustard (Brassica nigra) that I never would have dreamed could be redeemed. Yet here we are a decade later and it has been transformed into a thick blanket of black, white and purple sages. I asked Steve Davis, a landscape architect who helped design the initial garden, how this was done and he cited mulch and hand pulling of mustard.
As for the beneficial effect of sloping terrain, I bring Anisodontea x hypomandarum as proof. I have never seen this plant live for more than a few years in anyone’s garden. Even if it gets nothing but winter rain, it is susceptible to root rot where soil is not perfectly drained. But here, in the South African section, it has reached enormous size and is the picture of health after many years in the ground.
Another example of the power of this location is an Australian peppermint willow (Agonis flexuosa). I was astonished to learn that this glorious tree was planted only 27 years ago from a 15-gallon container. Its girth and muscular limbs make it look like it has been there for a century at least. Its symmetry is matched by a nearby specimen of the Queensland bottle tree (Brachychiton rupestris).
Alstroemeria highlights the Chilean section, which has only recently been added. The alstroemerias we see in our gardens are hybrids between winter-growing Chilean species and summer-growing Brazilian species. These hybrids are virtually evergreen, experiencing only a brief winter dormancy period. Alstroemerias can survive drought and neglect due to their sustaining underground rhizomes. Rich in starch, these rhizomes are part of the diet of the indigenous peoples who live within the alstroemerias’ habitat. Angel’s trumpet (Brugmansia) is another Chilean selection.
The animal that gives Conejo (meaning “rabbit” in Spanish) Valley its name is the only major pest to contend with at the botanic garden. Chicken wire encircles plants known as rabbit munchables.
Generally speaking, plants with strong fragrances or flavors, including rosemary and pungent sage species, are not eaten by rabbits. Lomandra, an Australian grass with chartreuse and lime green foliage, is also immune to rabbit ravages. Alstroemeria contains a toxin that causes some animals to stay away, while others become ill from its consumption. Not taking any chances, the garden surrounded its recently planted Alstroemerias with chicken wire.
One of the most eyecatching species from South Africa is Euphorbia esculenta. The plant is currently at peak bloom and its flowers at a distance look like daisies. I learned it is easy to grow, and I only wonder why we don’t see it more often. Davis told me many of the selections on display have been planted with the homeowner in mind. The plants are not only meant to be looked at but will serve admirably as durable, out-of-the-ordinary choices for the average garden .
To this end, several infrequently seen rosemary cultivars have been planted. An example is Tuscan Blue, whose stems shoot up in all directions, producing a pyrotechnic effect. The stems are studded with royal blue flowers. It would make a wonderful complement to Torch Glow bougainvillea, a cultivar whose magenta bracts are festooned along shoots that grow out in all directions, similar to the growth habit of Tuscan Blue.
Two germanders (Teucrium species) are looking brilliant at the present moment. Creeping germander (Teucrium cossonii), not exceeding 6 inches in height, spreads out to 3 feet and is coldhardy and drought-tolerant. Lavender to purple flowers are seen throughout spring and summer, but even in its present flowerless state it is something to behold due to its small, daintily scalloped, sea-green foliage. Bush germander (Teucrium fruticans) is a shrub that can grow up to 5 feet tall and wide. Blue flowers contrast nicely with silverygray foliage.
No selection for dry shade is more sensible in our part of the world than hummingbird sage (Salvia spathacea). It grows under oak trees and can go the entire summer without water, although it will stay greener in the hottest weather if occasionally soaked. Thick, upright magenta flower clusters are accompanied by foliage that emits a pleasant scent when crushed. Hummingbird sage is distinguished from other native sages by its rhizomes, the same structures that allow bearded iris and agapanthus to spread. You can plant hummingbird sage in the shadiest part of your garden and, as long as the soil is consistently mulched, it will just grow and grow and grow.
I was met at the entrance to the botanic garden by Beverly Brune who, together with Robin Pakorski, has been responsible for fundraising for development of the 33-acre site. I was introduced to Carl Zhu, who coordinated a drone flight over the area as a project for local students. The drone photographed tree canopies to evaluate them for carbon dioxide uptake. Trees absorb carbon dioxide through their leaves for photosynthesis, a process that on a large scale reduces air temperatures.
Zhu is responsible for the aviary filled with finches in the Kids’ Adventure Garden. His wonderful photographs are to be found at ConejoValleyBotanicGarden. com, which was designed by his daughter. Thanks to Davis for guiding me through the garden and to Jim Allyn for inviting me to visit.