How to Master Bonsai in the Desert
By Lori A. Johnson | Photography by Carl Schultz
The ancient Japanese art of bonsai is traditionally a slow form of gardening that requires years of patience to achieve ideal results, but there are shortcuts to training a tree or shrub into an aesthetically pleasing shape if you choose the right plant. While many native and desert-adapted trees, such as acacia, bursera, ficus, ironwood, juniper and olive make excellent candidates for bonsai, one of the splashiest specimens is bougainvillea, with its bursts of colorful blooms that occur several times a year. Most gardeners use bougainvillea to create swathes of color over large areas, so they may be surprised to learn that the plant is just as beautiful in miniature form. “Bougainvillea is commonly used in bonsai in milder climates and is perhaps one of the easiest bonsai plants in the low desert for beginners,” says Tom Gatz, an assistant mentor with the Phoenix Bonsai Society.
While most bonsai species take years of training before they reach their desired size and shape, bougainvillea is a notable exception that can provide as close to instant gratification as is possible and can often be displayed within a few months of creation or after just one growing season. “The foliage and mass of flowers quickly grow enough to hide any flaws that might take years to fix with more traditional material,” Gatz says.
Any variety of bougainvillea can be used to create bonsai, though in Gatz’s experience those with red blooms, such as Barbara Karst, seem to perform best in the desert. Other showy varieties include California Gold, the variegated-leafed Bengal Orange and the deep reddish-purple Alexandra.
One caveat is that in bonsai form, bougainvillea are frost-sensitive and need to be moved indoors when winter temperatures reach the freezing point, because their shallow pots make them more susceptible to root damage. Of course, they may also live indoors year-round, given sufficient window light. When displayed outdoors, they also require more frequent watering than full-size bougainvillea planted in the ground, as often as every other day during the hot summers.
To start a bonsai bougainvillea of your own, Gatz recommends choosing a one- to five-gallon nursery plant with a relatively thick trunk that tapers toward the top. Determine a desired height for your tree in the 15-to-20-inch range and cut off anything growing above that point. Transforming the bush into a miniature tree begins with removing all branches on the lower third, as well as any branches that are growing straight up, down or toward the trunk. Leave the longest branches near the bottom of the tree, with progressively shorter branches moving up the trunk. Once your tree has its general shape established, set it outdoors in full sun and water deeply every few days, fertilizing monthly with a low-nitrogen fertilizer. Several times during the growing season, cut stems back drastically, leaving only a few leaves to prevent the tree from growing back into a tangled shrub form.
Once the tree reaches its desired shape and ideal size, it’s ready for transplanting to a decorative bonsai pot filled with fast-draining soil, such as cactus mix (much of the root system will need to be removed in order to fit in the pot). Finish with small gravel as top dressing. After each bloom cycle starts to fade, cut the new growth on all branches to just a few leaves to maintain the bonsai height and form for the life of the plant. “It is claimed that the oldest bonsai trees may be more than 500 years old,” Gatz says. “We haven’t been using bougainvillea long enough to know their lifespan in a bonsai pot, but I suspect with good care, feeding, occasional root-pruning and repotting to rejuvenate the soil, they could last for as long as 30 years.” However, it’s still unknown whether they’ll live as long as traditional “legacy trees”—bonsai with such long lifespans that they outlive their owners’ ability to care for them and are handed down to the next generation of caretakers, Gatz says.
Bonsai containers come in a variety of shapes, colors and materials, with ceramic pots either glazed or unglazed, but one thing they all have in common is their shallow depth of just 2 to 3 inches. Important factors to consider when choosing the right pot are the tree’s stylistic gender, its size and the overall design. The style and lines of your tree determine whether it carries traditional feminine or masculine characteristics, such as fine-lined grace and delicacy in form versus thick-stemmed strength and density of trunk. Pot shapes echo corresponding characteristics, such as shallower pots in soft, flowing shapes for feminine trees versus deeper, stocky, squared-off shapes for a more masculine look. A rule of thumb for pot color is to choose one that complements the tree, resulting in a harmonious overall composition.
For beginners, bonsai societies in Phoenix, Scottsdale and Tucson provide hands-on workshops, demonstrations and lectures from local experts. These can be especially valuable when creating bonsai from desert-adapted trees such as bougainvillea.