Monday, December 3, 2012

The Manzanita!

One of the greatest joys as a designer of native gardens in California is working with Arctostaphylos, a.k.a., Manzanita. I can trace my interest in these plants all the way back to my early childhood. One of my favorite pastimes at this early stage of life was taking roadtrips with my grandpa to the backcountry of San Diego County. We would drive up Old Highway 80 to a roadside spring known as Ellis Wayside rest stop where we would eat lunch at a picnic table under the Oak trees.

I was fascinated with the history of that meandering old concrete highway and the circuitous path it wound through giant boulders jutting out of the chaparral. Manzanita covered the hillsides and I remember being intrigued by their smooth red bark and how green the country side was year-round. 

Today, estimates vary with regard to how many species of manzanita exist throughout California’s Floristic Province; from forty into the hundreds if you include cultivars, subspecies and hybrids. 

Arctostaphylos is a diverse group with varieties occurring in Mediterranean areas with predominately clay soils, sandy beaches, and colder mountainous regions made up of rocky acidic soil. Manzanitas are typically located in regions where the heat and dryness of summer are offset by cool air in the evening coupled with higher rainfall totals in winter. This is especially true of most of the cultivar and hybrid species grown for landscape purposes in California. 

Utilizing cultivars and hybrids in native gardens is a common-sense approach with regard to availability as well as a way to honor the people who have championed the use and preservation of California’s native flora.

A perfect example is Arctostaphylos densiflora 'Howard McMinn'. This plant was a selection introduced by the Saratoga Horticultural Foundation in 1955. The original plants were provided to them by Howard McMinn, who discovered and collected seed from a stand of Vine Hill manzanita near Sebastopol, Ca. It is fitting that this outstanding selection was named for him reflected by the Award of Merit from the California Horticultural Society in 1956. Howard McMinn Manzanita is also a nectar source for the Monarch Butterfly and a great addition to the butterfly garden

Arctostaphylos 'Lester Rowntree' is another hybrid with a rich history; its parentage  A. pajaroensis manzanita introduced by Rancho Santa Ana Botanic Garden and named for early native plant pioneer in the study of California native plants Lester Rowntree. Rowntree was known for drawing heavily upon her extensive fieldwork and writings regarding our native flora's natural history and how these plants would behave in domestic gardens.

Another excellent choice for the home landscape is Arctostaphylos bakeri ‘Louis Edmunds’. Like the aforementioned, Louis Edmunds is an upright variety that can adapt to many climates making it an excellent choice for a screen or as a focal point. The open habit of this manzanita shows off its beautiful chocolate branching habit, which contrasts well with glaucus leaves. Clusters of pale pink urn-shaped flowers bloom in late winter or early spring offering hummingbirds a good nectar source when few other natives are in bloom. 

Louis Edmunds Manzanita is a horticultural selection of Arctostaphylos bakeri from the northern coast discovered by plantsman Louis Edmunds and introduced by Saratoga Horticultural foundation in 1962. This hearty selection works well in sun to part shade and can tolerate more water than most manzanitas.

I certainly would be remiss in neglecting to mention Arctostaphylos 'John Dourley'. A personal favorite of mine, this hybrid is a dependable ground cover with a mounding habit 2’ tall by 6’ wide. New growth foliage has appealing red tint fading to gray-green during summer months. The clusters of pink flowers are abundant over a long bloom season followed by purple-red fruit. A. ‘John Dourley’ was named for John Dourley (horticulture director at Rancho Santa Ana Botanic Garden during the 1970’s) by native plant champion Mike Evans of Tree of Life Nursery fame. 

Manzanita has a rich history in California. Beyond the aforementioned historic figures outlined above, California’s Native Americans utilized the decorative berries and leaves for beverages such as tea, extracts for headaches and lotion for relief from poison oak.

Today as forward thinking landscape professionals and homeowners, we can use manzanitas to replace imported plants like Rhaphiolepis (Arctostaphylos 'Howard McMinn'), Privet (Arctostaphylos 'Mama Bear'), Escallonia, (Arctostaphylos 'Howard McMinn' or 'Sentinel' ), and Abelia (Arctostaphylos 'Sonoma').

From child to adult, Manzanita has continued to hold a special place in my heart. I have always been and will continue to be grateful for Mother Nature’s gift to California, the manzanita!



Friday, September 28, 2012

Shrubs of Chino Hills State Park

As a native plant garden designer or home gardener, understanding how plants are naturally arranged in their environment is critical. Understanding what species occur together in their plant community takes this understanding a step further. Several plant communities exist within the boundaries of Chino Hills State Park in Orange County, California. The lower elevations in the western-most region of the park consist of primarily coastal sage scrub.

Coastal sage scrub exists primarily from San Diego to San Francisco. Several key plants occurring in this particular plant community are summer deciduous. These plants are valuable in the native plant garden and worth being included on your plant palette even though their summer dormancy presents challenges on an aesthetic level. There are many plants that make up the coastal sage scrub plant community, but none as predominately as Artemisia californica.

Artemisia californica (foreground above) also known by the common name California Sagebrush, is what is known as an indicator species. Basically this means it is the primary or dominant species in this particular plant community.

Artemisia californica thrives in full sun, preferring to grow on south, west-facing slopes. It requires little water and prefers no water in the summer months. A. californica relies on wildfire for seed germination, and is often claimed to be allelopathic. Plants that have this trait are known to secrete chemicals into the surrounding soil which inhibits other plants from growing in proximity.

This factor may account for its dominant status within the coastal sage scrub community. It is an important habitat plant for the endangered California Gnatcatcher which alone makes it a valuable plant for the native garden! It is also aromatic, filling the air space around it with an inviting aroma.

Along with California Sagebrush grows Encelia californica Coast Sunflower. From an aesthetic perspective this shrub is a perfect match with the aforementioned Artemisia californica. Its larger green leaves make for a nice contrast against the gray almost needle-like leaves of California Sagebrush.

This plant is a perennial typically growing to four feet in height and width and is a regular in coastal sage scrub. It exists in chaparral communities as well but to a lesser degree usually being replaced by its relative Encelia farinosa.

Encelia blooms and greens up quickly following the first rains of autumn and will continue to do so through early summer sporting large yellow daisy-like flowers. A favorite with local pollinators Coast Sunflower makes yet another wonderful edition to the native landscape, both aesthetically and functionally.

Salvia leucophylla Purple Sage is another regular in the park. Growing in abundance in North Orange County, this variety of salvia occurs from near sea level to 2,600 feet in elevation. Purple sage prefers full sun and grows to 5 feet in height and width.

Purple Sage is known for its abundant pale purple flowers and aromatic foliage and is a favorite with hummingbirds as well as pollinating insects who are drawn to the nectar it produces. Like Encelia, Salvia leucophylla makes an excellent addition to any sunny California garden with its pale gray leaves and lilac flowers.

Along with Salvia leucophylla, Salvia apiana White Sage is a regular too. As its epithet reflects, it is preferred by both native and European bees. This plant was–and still is–a favorite with local Native Americans who utilize the seed in a flower mix that has long been a food staple. In addition it has lesser known uses such as shampoo and tea! White sage is still used today as smudge by tribes in traditional ceremonies.

All the aforementioned shrubs are key components in a healthy coastal sage scrub garden. They address issues such as habitat restoration as well as desirable elements like aroma and aesthetic value. As a designer or home gardener it is challenging to utilize summer deciduous plants, but with a little forethought and proper placement they can contribute to a beautiful landscape that everyone can enjoy!

Friday, August 3, 2012

Plant Profile: Trees of Chino Hills State Park

In my prior post I wrote about the importance of familiarizing ourselves with the flora and fauna of our local native ecosystems.  With regard to our native flora, trees make up one of the most important components of any ecosystem. They literally form the foundation of most plant communities and contribute greatly to local animal life.

In my area of Orange County, California, Chino Hills State Park is home to four main tree species, two of which are listed as rare and endangered. First on the list is Coast Live Oak Quercus agrifolia. Known by many as the ‘tree of life’ this type of oak is drought tolerant and evergreen, referred to as ‘live’ oak because of its non-deciduous nature. Coast live oaks have long life spans with some specimens in the park being over 200 years old.

Since my days as a kid, Coast live oaks have always been a welcome site due primarily to the cool shade they provide. Even more importantly are the benefits which these oaks provide for the natural ecosystem they occur within as oak woodland vegetation provides one of the most important habitats for animals.

With the tree's multi-branch habit and propensity to produce snags, oaks provide excellent roosts for raptors as well as nesting cavities for owls, wrens, bluebirds and other bird species. They also support myriad insect species and small mammals which make up critical food ladders. Fallen tree limbs become home for invertebrates as well. Woodlands create favorable environmental conditions by reducing wind and temperature variations compared to surrounding plant communities such as grassland, chaparral, and coastal sage scrub.

A companion to the oak is Sycamore Platanus racemosa, also known locally as ‘Aliso’. The sycamore is one of North America’s largest native broad-leaf trees, and is typically found in riparian plant communities. Unlike other tree species, P. racemosa tends to grow in scattered patterns of individual trees as opposed to typical groupings.  Sycamore leaves are very large often reaching ten inches in width. Like Q. agrifolia these trees can live between 250 and 600 years.

It is fairly common to find sycamore trees with hollowed portions in their trunks providing habitat for birds such as the great horned owl. Its large overhanging branches make superb nestling sites for a variety of birds and animals. Historically, Native Americans were known to use sycamore wood to make bowls and other cooking utensils.

Occurring in the dryer chaparral plant community, stands of Tecate Cypress Cupressus forbesii can also be seen. Listed as rare and endangered–and with only four natural populations found in the United States–this tree is one of CHSP's most prized plants! The entire range is found in southern California and northern Baja Mexico.

While Tecate Cypress is adapted to wildfire, it requires a 30 to 60 year fire interval. This time period is consistent with what is naturally required for trees to mature and produce an optimal number of cones. Unfortunately, the frequency of wildfires in its range has radically increased in recent years precluding trees from reaching maturity and producing seed.

On the other hand, efforts by the Irvine Ranch Conservancy and OCCNPS have yielded positive results with regard to maintaining remaining stands in the area, and with continued work the prognosis for the Tecate Cypress is hopeful.

Last and certainly not least, another of Chino Hills State Park’s special habitats is Southern California walnut woodland made up of Juglans californica. This species is considered rare and imperiled, with only about 1500 acres protected. Fortunately several hundred acres of this area occur within Park boundaries.

The original range of Southern California Black Walnut generally occurred from the Santa Clarita River Drainage in Los Angeles County south to the Santa Monica Mountains and east to the Puente-Chino Hills; with an area occurring in the northern part of San Diego County as well. Only scattered pockets remain today with land development the main cause of the walnut woodland’s decline.

These deciduous trees produce walnuts that are used as a food source by animal and bird species such as western gray squirrel, desert wood rat and scrub jay. Wildlife also utilizes its branches and understory vegetation as roosting and nesting sites. Native Americans utilized the walnuts as well.

Native trees are a critical component of any ecosystem. They are the ‘bones’ of the plant community and together with understory shrubs make up the foundation of most naturally occurring ecosystems and native landscapes. Their contribution both aesthetic and utilitarian is one of the true joys of experiencing nature first hand, and one of the best reasons to preserve and plant native species today.