Sometimes events do not turn out as planned. The project’s initiative was sound, but unknown factors appeared and turned success into a mess.
The sterling historical example of this concept can be summed up in one name, George Armstrong Custer. Panhandle Florida, however, has many lesser-known examples in the ornamental horticulture arena which have caused expense and aggravation over the decades.
A large number of the plants known as “exotic invasives” were originally imported as “robust” ornamentals. Even commercial agriculture has a few species which became notorious problems.
Creeping indigo (Indigofera spicata) is one such plant. A native of Africa, this plant is a legume.
Creeping indigo is maturing its seed in the heat of August. Unless clipped and removed, more of this problem plant will return next year.
Most legumes are viewed favorably by the agricultural community since they possess nitrogen-fixing bacteria in their root nodules.
Creeping indigo was introduced from Ceylon to Gainesville, Florida around 1925 as part of a research project to investigate several properties including nitrogen fixation and its potential as a forage crop for the livestock industry.
While this species was considered to have a good nitrogen fixing capacity, there were other features which appeared, but were not appreciated. Livestock toxicity issues began to be a concern of researchers as early as 1933.
When an early test as potential forage was conducted on rabbits, one did not survive the initial grazing trial. The surviving rabbit recovered after creeping indigo was removed from the diet.
Unfortunately, it had escaped into the wild by the time the negative attributes were confirmed.
Besides rabbits, equines, cattle, sheep, goats, guinea pigs, and birds have also been poisoned by this exotic plant. Swine, demonstrating exceptionally good sense, will not eat this plant and have avoided it in feeding tests.
The low-growing spring blooms of this exotic (and toxic) species are often hidden in the grass. If one is located, more are likely in close proximity.
During the growing season, creeping indigo is a low-growing plant which lies over in a prostrate fashion potentially reaching six feet in length. Leaves contain seven to nine hairy leaflets and stems are hairy, too.
Flowers appear at the base of the leaves and contain numerous pink blooms during the summer.
Identification of creeping indigo in the late summer and autumn is aided by the very distinctive seed pod clusters. Seed pods are straight and approximately an inch long in densely packed groups of about one hundred pods per stalk.
These downward-pointing clusters are bright green when immature, but dry to a matte black. The pods easily shatter when bumped or struck by an animal and will scatter the tiny seeds within.
Another example is the tung oil tree. This native of China came to the U.S. in the first decade of the 20th Century as a crop with industrial potential.
Tung oil had a number of uses, especially in paints in the days before synthetic chemicals were developed. Political turmoil in the 1930s stimulated plantings as the offshore sources became much more dangerous to reach.
Just before America entered WWII, tung oil was declared a strategic resource and cultivation soared. The plant also escaped into the wild and became difficult to control.
As manufactured alternatives became available, interest in this tree dissolved and many were destroyed. Still, it remains as a prolific seed producer which pushes out native species.
Today all the accumulated benefits of these imported plants have been negated as they became pest species. Even with the best laid plans, the unknown negative traits outweighed the benefits and now everyone has to live with the problem.
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