NABF Newsletter #8

Feature #13

California Juniper (Juniperus californica)

By Jerry McNey
Fullerton, California

They are often large, with a massive trunk, display shari, jin, and in some instances, heavily carved to display movement. The bare weathered silver-gray wood and narrow dark gray-brown lifeline are quite stunning set off by rich green foliage. In California, the tree is often a California Juniper (Juniperus californica). Old timers, often refer to its Japanese name of Kashu Shimpaku, meaning California Shimpaku.

The most noted and successful stylist for the California juniper is Mr. Harry Hirao of Huntington Beach, California. In the many conventions where he has demonstrated and had workshops, he is "Mr. California Juniper," and to everyone he meets, he is Harry. Much of the California juniper styling seen in shows is the results of Harry's teaching and workshops, or demonstrations. For several years, essentially all of California junipers seen in shows were the result of going with Harry to collect trees or from his efforts.

Early on, Harry met landowners in the Antelope Valley, north of Los Angeles, and talked some of them into allowing him to bring groups from bonsai clubs to dig junipers on the owners' land. With this permission and Harry's guidance, the serious collection of California junipers began. He has single handedly shown that an excellent bonsai can be created from the California Juniper. He has made a lot of people very happy.

Trees cannot be collected from forestland or private property without permission or a permit. For a long time, Harry has been able to resolve this by promising that the folks would backfill the holes, drive on established roads, and stay clear of the livestock. As a result of Harry's effort, a lot of trees have been collected.

The California's range from the west coast mountains of Baja Mexico up into the southern California deserts and foothills of the Sierra Nevada mountains and on the west side of the San Joaquin Valley and to some extent, northward to Oregon. The California’s are collected where there is low rainfall, large range in temperature, and strong winds that contribute to the natural twisted branches and trunk. The trees usually are found in elevation between about 3000 feet (900 m) and up to about 4500 feet (1,200 m), perhaps higher locally. The dry and somewhat hostile habitat contributes to slow growing and shrub-like growth, which is limited to about 12 feet (3.5 m). Usually, collected trees are old but shorter, less than 8 feet (2.5 m). Some prefer smaller trees. When they are styled, it is often driftwood, contorted with bare wood and minimal green pads, or they are modeled after examples of the bristle cone pine, found in the White Mountains in eastern California.

The tree has an interesting personality. Seedlings start with a single trunk, but in a few years they have many buds pop out for low branches. When young, it grows in shrub-like clumps, with single branches growing out from the base, and with sufficient water, looks like a big bush. The juvenile needles are pointed around the circumference and mature into scales similar to shimpaku (Juniperus chinensis var. sargentii). The old bark is ragged and gray. When cleaned off for a show, it can be brushed down to the reddish brown new bark. When trimmed, new growth will selectively pop out along secondary branches, usually at a crotch where there is a fork, or occasionally on the trunk. Gray-green seedpods form on the female plant; the male has small yellow flowers. The female is preferred when collecting. It seems a bit hardier, and some folks look for the seeds while considering the shape and branching. As the tree ages, particularly where ground moisture is sparse, the branches thin out, and some branches break off or bend down to the ground. Occasionally, these low branches become covered with soil, and after some time, take root, but seedlings are the most common reproduction method. The large bush-type junipers are usually along drainage courses or in less hostile locations. The contorted trees are found on the south- and west-facing windward slopes of the mountains and along the ridgelines where the winds carve and bend the branches.

The California juniper grows in the arid desert, the foothills, and on bedrock ridges and slopes. Tight needles and branches are found on the south and west exposed sunny slopes. Trees on the north, shady sides of the ridges, usually are less stressed, have more branches, and grow larger as do the trees found along creeks and protected areas. The trees propagate by seedlings that produce a taproot to support much of the tree growth and development. As the tree matures, a shallow 6 inches to 12 inches (30 cm) deep, the root system develops to support the additional vegetation mass. As noted earlier, live branches may root in the adjacent soil when conditions permit. The climate in much of the growing regions is desert, 10 to 12 inches (250 to 300 mm) of rainfall a year, and this is during the winter months. Little measurable rain falls in summer and fall. Although there are occasional monsoon rains from the south, they are of short duration, and because of rapid runoff, probably contribute little long-term soil moisture. During the summer nights, as temperature falls, the humidity increases, and because the juniper needles absorb moisture at night, there is some moisture replenishment.

Winter temperature often swings 40 to 50 °F (about 25 °C) in a day’s period -- from at and below freezing overnight and going up to the 50's and 60's or above during the day. Summer may have days where it is not unusual to be in the 60's overnight and over 100 °F (38 °C). during the day. These temperature extremes are often accompanied by strong winds that add stress to the trees affecting the growing pattern and stunting the growth.

The California juniper grows very slowly as a result of the harsh environment. On occasion when a juniper doesn't survive the collection and transition to a pot, the tree trunk has been cut in two and the tree rings counted. The close growth of rings requires a magnifying glass to count, and the estimated growth rate of ¾ inch (2 cm) per 100 years was calculated. This count may not include a very dry interval when there was essentially no growth, nor the possibility of accelerated growth and possible multiple rings during heavier periodic rain.

The California juniper is a collected tree. They propagate by seed; they are not candidates for cuttings. Some air layering is accomplished but it is a very long-term effort. The collecting is a bit of work because of the desert environment and usually difficult terrain. The trees are collected after a rainfall or two when the soil is soft. In deciding which tree to collect, the challenge is to imagine what the tree will look like when it is trimmed back. Then, the excess branches are removed to see what the finished, styled tree might look like. The California juniper is very sensitive to root disturbance. When collecting and potting, great care is taken to minimize damage to the fine white roots, and the tree is well anchored against movement in the pot until new roots are established. The tree is placed in the semi-shade for six months to a year, and watered to keep damp until new growth pops out and firms up. The potting medium is usually washed agricultural pumice because of the excellent drainage and moisture retention. Mixing in fresh crushed granite adds some nutrient and maintains drainage. Fine clays and heavy organic soils retain too much moisture.

The slow growth and contorted natural branch placement creates a tree with well-developed movement. Styling is a bit of an art because there is no real definition of how the tree should look but is left only to the artist's imagination and what the tree will allow him to create. The show trees range in size from two- to four-man pots, down to Shohin, less than eight inches (20 cm). They create a memorable example of bonsai. The cutting of the tap root, moving to lower altitude, change in climate, different soil and new watering are all stressful and lead up to a rather small number of California juniper's that survive to one day be in a show. The successfully grown and styled tree in a complementary bonsai show pot, however, makes the hot day digging, long recovery, hours of wiring and trimming, and patient watering worth the effort.