IN THE GARDEN LOVE-HATE RELATIONSHIP BLOSSOMS WITH BOUGAINVILLEA.

Byline: JOSHUA SISKIN

Your relationships with plants, like those with people, may undergo radical changes with time.

Plants that you thought were the most beautiful on earth when you started gardening may look far less attractive as you learn more about them through close contact on a daily basis.

By contrast, plants that you thought were boring or predictable upon first acquaintance may suddenly, after years of knowing them, seem possessed of subtle yet lasting grace, mystery and beauty.

And then there are plants you may initially love, after a time begin to hate, and then, one day, begin to love again.

Consider bougainvillea, acceptably pronounced as either boo-gan-VEE-ya or boo-gan-VILL-ee-ya. If you come to California from a place like Chicago, as I did, your first impression of bougainvillea is bound to be a positive one. Its many varieties in red, pink, fuchsia, purple, orange and white show their colors virtually throughout the year, and, after their first summer in the garden, need no irrigation.

You might not think a tropical plant such as bougainvillea would grow well in drought conditions, but the truth is that many plants from the tropics, because they grow on volcanic, sandy or other quickly draining soil, are accustomed to living without much moisture around their roots. Oleanders and many types of palm trees are other examples of drought-tolerant tropical species.

Despite their toughness, bougainvilleas have extremely delicate roots and are impossible to transplant from one garden spot to another. Planting nursery-grown bougainvilleas from the plastic containers in which they were raised, especially in warm weather, can also be a challenge. Before planting, cut off the bottom of your bougainvillea's container, but leave the sides intact. That way, the root ball will stay together and you won't have to worry about wilting, as sometimes happens when the entire container is taken off prior to planting.

Once the plants have begun to establish themselves after their first summer in the ground, the rest of the container can be cut away.

Your romance with vining bougainvilleas may end the first time you have to prune them. With time, vining bougainvilleas often begin to look somewhat trashy, as lots of their colorful bracts, or modified leaves, are deposited and turn brown within the thickets of thorny branches that describe the mature specimens.

Also, the branches on the lower portion of the vines tend to defoliate. Take it from me: Do not attempt to artistically prune these plants. Take your loppers and chop away. They will grow back soon enough. Purple bougainvillea has a shrubbier growth habit than the other colors and is the best candidate of the group for use as a flowering hedge, although it will also grow as a vine if given wire or fishing line to guide its growth.

The `Raspberry Ice' variety, with cream and green variegated foliage and red flowers is the best container selection. `Torch Glow,' as its name implies, has discrete branches that grow out from a single point, each terminating in a blaze of fiery red.

The most well-known relative of bougainvillea is the four o'clock (Mirabilis jalapa). This remarkable plant flowers in the afternoon and early evening, wafting a mild fragrance while attracting pollinating hummingbirds and moths. Like bougainvillea with its thorns and eventual messiness, four o'clocks are disparaged because of their rampant growth. Here, though, the issue is prolific self-propagation underground. Mature four o'clocks develop indomitable tubers that must be completely dug out for the plants to disappear. Moderately watered in sun or partial shade, four o'clocks are covered with red, yellow, pink, purple, white or multicolored trumpet blooms for much of the warm season. Due to their competitive nature, they are not meant for pristine flower beds, but demand their own space where, unimpeded by neighboring annuals or herbaceous perennials, they can properly show off. Four o'clocks are the ideal ground cover beneath trees with troublesome surface roots, such as sycamores and magnolias, where nothing else will grow.