Dear HCN,
I was surprised to see
science fiction in High Country News (-It rhymes with scourge,”
HCN, 6/22/98). First it was the Yellow Peril, then it was the
Russians and Men from Mars, and now we have invasions by hordes of
alien plants unwittingly let loose by
gardeners.
It’s true that Euphorbia myrsinites
(donkeytail spurge), which has been cultivated in this region for
many years, has escaped from Boulder-area gardens and established
itself in some areas. It’s not taking over “prairies and foothill
meadows.” It’s not a “fast-moving, aggressive invader.” It will not
“soon be everywhere.”
The article constantly
confuses introduced weeds which have invaded (but not “infested’)
some areas of the Rocky Mountain region with introduced
ornamentals, of which Euphorbia myrsinites is the single example.
Evan Cantor seems unclear as to which plants are native and which
are not: “…dandelions, salsifies, thistles, chicories, henbit”
aren’t native plants and don’t “possess an ancient claim to their
presence here.” The “wild rose” was not introduced by “European
gardeners’; there are about a dozen rose species native to the
United States. The term “naturalized” refers to an exotic plant
which grows in the garden or in the wild as though it were native.
Tamarisk is most certainly a naturalized
plant.
Contrary to the author’s assertion, it’s
quite possible to have a “waterless garden’ – I have had one,
planted with native dryland plants, for many years. The article
makes the statement that xeriscape isn’t environmentally sound
because “saved water gets appropriated for new development.” Now,
really … this is absurd. Xeriscape is banned all up and down the
Front Range; most developments have covenants that prohibit
xeriscaping. The proliferation of Kentucky bluegrass lawns and the
concomitant habitat destruction is surely a far more serious threat
to our ecosystems than exotic plants naturalizing in the
wild.
The criticism against xeriscape is better
leveled against “natives only” gardeners themselves. The facade of
plant purity often conceals something less than the environmentally
friendly landscapes “natives only” gardeners claim they are
promoting; witness a well-known “nativist” garden writer’s lavish
praise of “natives only” plantings in an Arizona “golf course
community.”
The threatened “colonization and
naturalization” of plants from other dry-climate regions is a
fantasy. I have grown about 2,000 species of plants from these
regions, and few have shown any “irreversible” tendencies to invade
native habitats. Unfortunately, garden writers who recommend plants
from climates similar to our own frequently give the false
impression that the plants are perfectly adapted to the climate of
the Rocky Mountain region. The majority of these plants need
supplemental irrigation in our climate and are really being watered
about as regularly as are other garden
plants.
About 50,000 species of ornamental plants
have been cultivated in the Rocky Mountain region in the last 40
years. The percentage of these that have escaped and are now taking
over every inch of available ground is minimal. Plants will only
grow where they are adapted; most ornamentals grown in Colorado and
elsewhere in the Rocky Mountain region are ill-adapted to survive
outside the confines of a garden.
The author
claims that “an innocent garden flower could trigger an ecological
nightmare.” A more plausible scenario would be one in which seed
pods from outer space, tended in a secret horticultural facility
near Area 51 in Nevada, escape from confinement and turn into
man-eaters, devouring every tourist in
sight.
Robert
Nold
Lakewood,
Colorado
This article appeared in the print edition of the magazine with the headline Sorry, no alien invasion here.
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