GARDENING : BAUHINIA: A PLANT NAME WORTHY OF BOTANICAL BROTHERS.

Byline: Joshua Siskin

The greatest compliment that can be paid to a botanist is to have a plant named in his honor. But if two great botanists happen to be brothers, what then? If a plant is given the brothers' family name, will there not forever be a doubt as to which brother was being honored, with a question always raised about the comparative greatness of each?

Where the brothers Bauhin were concerned, this problem was solved in a most felicitous way. Johann and Caspar Bauhin lived in Switzerland in the 17th century. Each wrote classic works on the cultivation, economic uses and nomenclature of plants. In the 18th century, Europeans first discovered a tropical genus of small- to medium-sized trees with twin-lobed foliage. Here were the ideal plants whose twin-lobed leaves would forever serve as a reminder of a brotherly botanical legacy to honor the illustrious Bauhins. And so the genus name Bauhinia was born.

Thoughts of the Bauhin brothers crossed my mind the other day. Taking a route I had never traveled before, I found myself gazing at a magnificent Bauhinia tree on the corner of Gothic Avenue and Parthenia Street in North Hills. Plant lovers are known for varying their daily commute in order to observe the flora in different neighborhoods. Plant lovers are always on the lookout for something new and unusual, especially when it is more than a few years old and in good health.

It is no big deal to wander into a nursery and find some unusual plants that transfix the eye. Often, though, these plants prove difficult to grow and frequently, when planted around the house, go into immediate decline. The dichotomy between luxurious growth in the nursery and sparse growth in the garden is both soil and climate related. Nursery or containerized plants grow in soft, custom-tailored soil, much different than the obdurate, alkaline soil in most of our yards and gardens. In addition, many plants in our local nurseries have been raised in coastal areas. The climate along the coast is far more benevolent to plants than our own inland climate. Coastal-grown plants may not belong here at all and, in any case, should be expected to lapse into shock when planted here.

The species of Bauhinia at Parthenia and Gothic appears to be the purple orchid tree, Bauhinia variegata. It is the most commonly seen orchid tree in our area and has flowers that range from pink to purple, depending on the cultivar. It requires staking for many years until it can finally stand on its own as a tree. If left to its own devices, it will sucker profusely and grow into a large shrub.

There are more than a dozen species of Bauhinia that are grown ornamentally in climates such as ours. The Hong Kong orchid tree, Bauhinia blakeana, is worth special consideration. This tree, with 6-inch multicolored red, pink and purple blossoms, was thought until only recently to be a hybrid, the result of a cross between two different parent species. This conclusion was drawn from the fact that the thousands of Bauhinia blakeana trees growing in Hong Kong, whose municipal emblem is this same tree's flower, were not found to produce viable seeds; the inability to reproduce sexually, whether we are talking about mules or seedless watermelons, is often an indication of a hybrid status. The only way the Hong Kong Bauhinias could be propagated was by shoot cuttings. However, a few years ago, a single tree thought to be Bauhinia blakeanas did produce viable seeds. Hong Kong University is investigating the molecular and genetic structure of this unique tree to see if it matches that of the sterile Bauhinia blakeanas.

People who think they may have a Bauhinia blakeana can be close to certain they do indeed have one if no seed pods are produced two weeks after the flowers fade.

Tip of the week

A number of readers have sought counsel regarding pruning of plants that were burned in December's freeze. To be completely safe, no pruning of these plants should be done until the middle of March, by which time the danger of frost is over in Los Angeles. Last year, for example, we had a freezing night in late February.

Most established plants should recover from December's freeze. Already frost-damaged bougainvilleas and ficus trees are showing new growth. Pruning them, however, will stimulate lots of succulent, tender growth that could be damaged in another freeze. By the same token, some people are already planting tomatoes, germinated indoors, in the garden. They put plastic containers over their plants each night to protect them from the cold. This is not a risk-free proposition, but the thought of early tomatoes makes the risk worth taking.