Careful Start Gives This Plant Big Boost

Question: I have had trouble getting bougainvillea established in the past. When is the best time to plant it, and what can I do to increase my success with the plant?

D.D., Anaheim Hills

Answer: The very best time to plant bougainvillea is in early summer. Select an area in full sun. The root area should also receive full sun. In hot inland valleys the plant can grow well in light shade.

Bougainvillea is very fragile when young and can be easily lost at planting time. Its roots and crown are so loosely formed into a rootball that it often falls apart when removed from the container in the typical manner.

Below are some tips on how to plant and successfully grow bougainvillea:

* Dig a hole two times as wide as the container and the same depth. Loosen the soil at the bottom of the hole and add bonemeal, gypsum and a slow-release fertilizer, according to package directions. Make sure that the

hole is the proper depth so that

the crown of the plant will be

even with ground level when planted.

* Set the plant (can and all) into the extra-wide hole you have created. Take a pair of sharp needle-nose shears and insert the blade into one of the drainage holes and carefully cut around the bottom of the container. Slide this bottom piece out.

Next, carefully make a slit down the sides of the container in several places. Fill in with native soil around the rootball and carefully slide the detached pieces out.

* Create a watering basin and water deeply. In light, fast draining soils, you will initially need to water two to three times a week. After the first month or so, water once a week for the next three years. In heavier clay soils you should water enough that the rootball is kept on the damp side (not soggy) for the first month or so.

After that, water deeply only after the ground dries out. The plants have deep taproots that access underground water sources and become quite drought-tolerant once established. When they are young, they can take quite a bit of water (as long as the drainage is adequate).

To encourage flowering, stop watering established plants around July. Many experts recommend never watering bougainvillea that has been in the ground more than five years.

* Bougainvillea does not require heavy fertilization. You may want to consider feeding it once a month from April to August while they are becoming established. After three to five years you can stop fertilizing them in summer. Remember that container-grown bougainvillea will always need regular fertilizer and water.

* Consider doing some heavy pruning in spring. This is especially important on the tall vining varieties to keep their growth under control. Shrub types won’t need as much trimming.

Don’t prune in summer or you may not get any blooms. Avoid pruning in fall or winter or frost may damage the new tender growth that follows. Bougainvillea bloom (the color is produced by the leaf bracts) on new wood, so pruning at the correct time stimulates increased bracts (color).

* Provide sturdy supports for the tall vining kinds.

Have a problem in your yard? University of California Cooperative Extension (UCCE) Master Gardeners are here to

help. These trained and certified horticultural volunteers are dedicated to extending research-based, scientifically accurate information to the public about home horticulture and pest management. They are involved with a variety of outreach programs, including the UCCE Master Garden hotline, which provides answers to specific questions. You can reach the hotline at (714) 708-1646

or send e-mail questions to

ucmastergardeners@yahoo.com. Calls and e-mail are picked up daily and are generally returned within two to three days.