Sunday, March 14, 2010

By robin robinson Key West Garden Club

In May, the native Jamaican dogwood tree (Piscidia erythrina or P. piscipula) looses all of its leaves. Tiny pink flowers that look like minuscule hummingbirds form all over the ends of its branches. They are so sweet with nectar that the bees, wasps and insects are compelled to its blooms by the thousands. The entire tree looks as though it's quivering in the sunlight.

I live above one of these 45-foot trees and look down on this quivering mass of insects in the orgiastic sating of their hunger. It's like they found a tree of Godiva chocolate.

As sweet as the nectar of this tree is, when its leaves, bark and branches are ground into a powder and thrown into the water, they create a poison which stuns the nervous system of cold-blooded fish. The Seminoles threw the mixture into the water in order to pick the fish off the top of the water instead of catching them. Not very sporting, but effective when a tribe needs feeding.

Evidently, this paralytic effect doesn't occur when it is used with warm-blooded animals as the roots, twigs and bark have been used as a as a sedative, to reduce muscle spasms, induce sleep, relieve pain and reduce inflammation. The roots and bark have been used as a powerful narcotic similar to morphine.

The active ingredient is the chemical rotenone used in pesticides, insecticides and piscicides, a chemical substance poisonous to fish. The piscicides are used by fish nurseries to cull out unwanted exotics. This chemical is poorly absorbed by humans.

The intensity of the chemical differs when trees are grown in different kinds of soils just as food grown on organic soil differs from food grown in land that has been depleted. Although long used in traditional medicines, these medicinal effects are word of mouth as they haven't been studied by western medicine so it's not advised trying it out on yourself.

The scientific name of this fast-growing tree means little-fish killer and it is called variously Florida fishpoison tree, or better yet, fish fuddle. Even more interesting, the dogwood portion of the name comes from the boomerang-shaped piece of bent wood that is used on a ship's bow where the mermaid usually hangs out on the prow. It was made from this tree's strong, decay-resistant wood. It's good for building boats and fence posts. It grows so well that sometimes the fence posts get roots.

Jamaican dogwood's deciduous leaves are alternate and pinnately compound. Three-inch leaflets form in an opposite arrangement with as many as 10 on a stem. They are medium green above and lighter underneath.

Seeds are light brown with four papery wings holding red-brown seeds that flutter down in August. This member of the Fabaceae family germinates readily in eight to 10 days.

Our well-drained, nutrient-poor soils suit the Jamaican dogwood well. The fast-growing dogwood is tolerant of salt winds, drought, and short-term inundation by salt water.

It is used as an ornamental shade tree in tropical hammocks where it rises above the understory trees and enjoys the full sun that its height provides. It does not like cold weather and exists primarily in and below Zone 11. Mama's Garden Center can order it for you. A 15-gallon tree costs around $90.

It is the larval host plant for several butterfly species including: the native cassius blue butterfly (Leptotes cassius) and hammock skipper (Polygonus leo) and the introduced fulvous (yellowish) hairstreak (Electrostrymon angelia).

Pity the snowbirds who do not get to see this splendid tree in its full reproductive power.

Stop by the Garden Club to see the March flower arrangements based on the theme of transparency. The Garden Club also welcomes volunteers to pull weeds, propagate and play in the sandy soil from 9 a.m. to noon Mondays.

Master gardener Robin Robinson was a columnist at the Chicago Daily News and syndicated by Princeton Features. This column is part of a series developed by the Key West Garden Club, http://www.keywestgardenclub.com. A compilation of her columns, "Plants of Paradise," is available at the Garden Club.