The silk tree or so-called mimosa, Albizzia julibrissin rosea, maintains an uneasy balance between superlative virtues and nearly damning faults. Like the little girl in the nursery rhyme, when it’s good, it’s very, very good, and when it’s bad, it’s disastrous. The alias “mimosa” indicates a resemblance to the yellow puffball flowers with gray-green pinnate leaves sold by florists under that name; since these are actually acacias, the silk tree’s common name is even less accurate than most. However, the word “Albizzia” is as splintery as “mimosa” is smooth and evocative. With a shrug for consistency, I choose the pleasant name over the correct one.
The tree’s native range is from Persia to Japan. Bailey’s Cyclopedia states that it is hardy only as far north as Washington, D. C., but it grows vigorously on Long Island, and has weathered a drop to zero without visible harm.
While moderately severe cold is apparently not a factor of survival, the mimosa is critically vulnerable to damage by heavy rain and wind. It is excessively fast-growing, but what it gains in speed, it loses in strength: the wood is soft and pithy, not much sturdier than that of sumac. The crotches are especially weak and apt to give under the weight of the weeping branches when their foliage is sodden with rain. Our tree has split twice, once in a prolonged downpour, once in a hurricane – the latter nay fault for not shortening the branches when the first storm warnings came over the radio. I did go out resolutely with the lopping shears, but the profusion of flowers and the prospect of whacking off all the soft new growth with half a summer’s buds still unopened easily persuaded me that it might be a false alarm. My faintheartedness cost half the tree. However, growth is so rapid that the wound, chiseled smooth and coated with tree paint, healed in two years.
I am perhaps exaggerating the tree’s frailty: by comparison with others in the vicinity, ours must. be exceptionally weak, as it is the only one that has suffered such drastic damage. Still, it is only fair to give notice that the mimosa is by no means as sturdy as an oak, that it is a chancy thing, and that you mustn’t be too surprised or dismayed if you find one side of it on the ground some rainy morning.
If the mimosa is far down the scale of durability, it tops the list for its unique gift of producing an unflagging succession of fresh and charming flowers through the wilting dog days of July and August.
The color of the flower varies with individual trees: some are merely tinted with watermelon pink, others are fairly deep rose; all have a light-catching halo of gold dust tipping the thready stamens. Mature flowers usually drop in midafternoon when the new buds start expanding. The filaments as they first are released are as kinky as a bad permanent wave, but they straighten out as fast as pincurls on a rainy day. Newly opened flowers have a faint clover-like scent, which towards dusk intensifies into a heavier, pervasive fragrance.
Attracting Nature
The flower is clearly designed to attract nocturnal moths. Light-bodied butterflies give a daylight preview of the method: half walking, half fluttering, they stitch over the whole flower with their watch spring tongues. The silky shaving brush seems just as expressly designed to defeat bumblebees, but with them, determination outweighs their lack of streamlining: clasping bundles of slippery threads, and floundering around like cows in a hayloft, they manage to force their stout bodies to the nectar at the base of the filaments. Evidently they dislike the assignment, as they keep up a furious buzz of exasperation, and are so very short-tempered that taking pictures at close-up range involves a real hazard to the photographer.
The flowers open in progression from the trunk outward to the tips of the branches, and are displayed above the finely-divided leaves, languorous enough to grace a tree fern in a tropical rain forest. The long fronds are always in motion; even on the sultriest day, they lift, ripple and curtsy in the slightest stirring of air. No tree throws a more decorative or animated shadow: it would be perfect to plant beside a terrace, with its canopy of plumes tracing their fernlike pattern on the paving stones, IF – and here, inevitably, is the balancing fault – IF it can be placed where it isn’t visible from the main windows of the house during the winter, for, unhappily, its leafless stage is unimaginably ugly. At the first hard frost, everything falls off – leaves, twigs, side branches – exposing a grotesque naked and deformed-looking skeleton hung with dangling broad beans. To make things worse, the tree is one of the last to leaf out: its bare bones can be acutely offensive in the spring landscape.
Of course, at a summer cottage, this factor would be no handicap; in an all-year-round house, it may be impossible to use the tree near the terrace, since indoor and outdoor living areas are often centered together on the most desirable view and exposure. Modern houses, with their wide expanses of glass, aren’t apt to have a stretch of blank wall long enough to mask the tree between windows.
We had no such blind spot, so we put our tree in one corner of the plot near the street and behind the fence that surrounds the rose garden. Here is is out of the direct line of view from the dining and living room windows in winter, but is fully visible from the summer terrace, where its crown of swaying plumes, like a living mobile, dramatizes the first breath of coolness that signals the end of a scorching day.
by M Graff
