Oftentimes, when folks think about planting a bougainvillea or other drought-tolerant plants in their garden, they figure that all they have to do is pop the thing in the ground, water it, and, voilà, they have an instantly sustainable landscape plant that can immediately fend for itself. Not so, amigos.
Bougainvilleas have fragile roots and, apart from requiring extra care and diligence when planting one, getting it established in your garden and teaching it to be self-sufficient can often be a complicated case.
Initially they have to be kept evenly moist and not allowed to dry out, just like any other landscape plant. As the plant gets going, though, it should be encouraged to develop deep roots by watering thoroughly but less often. Their large and fibrous root systems will eventually go looking for a water source such as a nearby drip system, other irrigation areas in your garden, or even a leaky hose bib. It’s best to let the plant find its own water rather than irrigate it regularly with the rest of your garden.
In Pat Welsh’s indispensable Southern California Organic Gardening, the author gives step-by-step instructions on how to care for, irrigate, and establish a bougainvillea, beginning at the time of planting and continuing all the way up until the thing’s been in the ground for three years. “After three to five years,” she writes, “you can stop fertilizing in summer, stop watering in winter, and reduce the frequency of summer watering to once a month or every six weeks — or perhaps never, depending on placement and variety.”
Since bougainvilleas are so colorful, vibrant, and irresistible when displayed at the nursery, many people choose to grow them in pots or containers. Since most types are such vigorous growers, I find that after a few years, their roots fill their containers, and they begin to decline. If I do opt to enjoy them in pots, I look for the less vigorous or compact types and use the largest containers I can manage. I use a well-draining potting or cactus soil, and I feed them regularly during the warmer months when the plant is actively growing.
Keep in mind, too, that although bougainvilleas often require little or no supplemental irrigation when planted in the ground, in pots they should always be treated like any other container plant. The soil and the roots should never be allowed to dry out completely.
I emphatically recommend Welsh’s book — and not just for the bougainvillea tutorial she offers, but for all her practical gardening knowledge and wisdom. Not only is the book unique in that it is specific to gardening in SoCal, but it also gives the reader a month-by-month schedule of what’s to be done in the garden, including tips on feeding, watering, and pruning for individual plants. See patwelsh.com.