Breaking Ground 9


by Derek Burch

Years of movies should have alerted us to the insidious ways of aliens, infiltrating the very fabric of society before some chance question by a persistent child (what have these precocious brats themselves grown into?) finally gets the attention of the adults, who then gird for battle and go through extremes of agony to identify and slaughter the invaders.

It isn't a big leap to rewrite this story to feature some of the alien plants and animals which move, scarcely noticed, into an environment and reproduce so fast and successfully as to threaten the previous inhabitants. The precocious children would be the exotic pest councils, who nag at our consciousness, and sometimes turn out to be right in the warnings that they are trying to send.

We, the public and the industries who may unwittingly have helped the invaders, now have to face the agonies of realizing that some of our favorite plants (and animal pets) may just be tolerable if closely confined to the garden (or cage or aquarium or zoo) but cannot be allowed to go out on their own. The examples that have finally caught our attention are horrifying in terms of the damage to ecosystems that have been caused, and the draconian measures that will be needed to bring back some measure of balance.

We may have to lose some of our favorite plants because there is no sure way of confining them. The plants that grow well from seed have spent ages developing efficient dispersal mechanisms, and we would need to exclude the bird and small mammal partners and stifle the wind if we were trying to stop their spread. Brazilian pepper in Florida and purple loosestrife in some northern states are terrifying examples. Even plants that do not seed can get away from us if we are careless. I am thinking, as an example, of pothos (Epipremnum aureum), that stalwart of hanging baskets for the interior. When careless homeowners or irresponsible maintenance workers in South Florida dump their trash illegally out in the boonies, it doesn't take long for the clipping from their groundcover to root and start growing up any tree within reach.

Industry associations are helping with the problem by recommending that certain plants should be dropped from nursery inventories, but put their lists together with one eye on the dangers from the plants and the other on how willing the industry is to lose the revenue from the plants. Not exactly a responsible approach.

The problem in knowing what it is prudent to grow is not easily settled. Don't think that "native" plants are safe. They are only guaranteed not to change their character in the habitats in which they are truly native. We are reworking so much or our environment that a plant from the natural woodland down the road where it nestles unobtrusively in its niche, can become a roaring menace in the disturbed habitat a short distance away.

The Exotic Pest Councils are well-meaning, but not necessarily well informed, and tend to expand lists of harmful species simply on suspicion, and without taking into account geographical and climatic factors, all of which hurts their credibility. At the Federal level things have now become so bad that there is the threat of a "whitelist" of acceptable plants as the only ones which will be allowed to enter the country. Must we really freeze the spectrum of plants that we may use in this way?

What to do about this alien threat, then? Understand that it is real, and become informed about the reproductive capabilities of the plants that you grow. Control seeding on anything that seems particularly fecund, and don't think that an isolated plant in your garden "can't do any harm." Check out 'Day of the Triffids' if you haven't read it recently. It is a good read and may get you looking at those strange seedlings at the edge of the compost heap a little more carefully.

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