Plants out of place.
When I attended my first conference organized by the California Exotic Pest Plant Council, I expected to hear about the magnitude of the problem, as well as about new methods to combat the spread of invasive plants in California. I hoped to be encouraged by success stories and to relax in the company of those with similar awareness of the astronomical growth of this problem.
What I didn't expect was that the conference would be among the most interesting I've attended. Because it was about relationships between animals and plants, insects and plants, birds and plants, and fire and plants, dismaying news of the degradation of natural systems by exotic plants was balanced by a sense of revelation.
We heard stories about volunteers pulling broom and removing Cape ivy from the Santa Cruz mountains. There were stories about new uses of fire in the control of broom and yellow star thistle yellow star thistle
centaureasolstitialis. . There were stories about careful, thirty-year-long studies of sagebrush sagebrush, name for several species of Artemisia, deciduous shrubs of the family Asteraceae (aster family), particularly abundant in arid regions of W North America. The common sagebrush (A. land, of the desert tortoise desert tortoise
see gopherus agassizii. , of the Spartina Noun 1. Spartina - grass of freshwater swamps and salt marshes of Europe, Africa, America, and South Atlantic islands
liliopsid genus, monocot genus - genus of flowering plants having a single cotyledon (embryonic leaf) in the seed invasions in our wetlands. There were stories about pampas grass pampas grass, any species of the genus Cortaderia, tall South American plants of the family Gramineae (grass family) cultivated in warm climates for ornament. The common pampas grass (C. , tamarisk tamarisk (tăm`ərĭsk), shrub or small tree of the genus Tamarix, native chiefly to the Mediterranean area and to central Asia. The plants are often heathlike and thrive in arid and coastal regions. , Cape ivy, arundo grass, pepperweed, iceplant, and cheat-grass, all involving relationships in the process of disruption.
Many of these plants are still sold by California nurseries and planted by California gardeners, whose back yards serve as springboards for the spread of Cape ivy, capeweed, vinca Vin·ca
A genus of evergreens usually found in the Eastern hemisphere.
plant genus of Apocynaceae family; contains cardiac glycoside; causes diarrhea; includes V. major (blue periwinkle), V. , broom, iceplant, English ivy English ivy
see hedera helix. , passionflower passionflower, any plant of the genus Passiflora, mostly tropical American vines having pulpy fruits. Some species are grown in greenhouses for their large, unusual flowers of various colors; those seen by early Spanish settlers were interpreted as symbolic of vine, pampas grass, and acacia. Not a few gardens in my town consist solely of such species, often donated by other gardeners, who, understandably, "have more than they need."
With strip-mining or clear-cut logging, negative consequences are evident from the first. The disruption of natural processes that comes with the invasion of native plants may not be obvious for a while. Once it's too late, we can evaluate the loss of good grazing that follows the invasion of cheatgrass and yellow star thistle, or the compromising of dune ecology that follows the establishment of European beach grass, Ammophila arenaria.
Slow, steady erosion of natural values resulting from the choices made by gardeners is evident in many situations, from public lands to private holdings. Old house sites in national parks demonstrate the consequences of early horticultural choices. A hike into the southern end of Point Reyes National Seashore Point Reyes National Seashore (rā`ĭs), 71,068 acres (28,772 hectares), W Calif.; est. 1962. Included in the area are steep bluffs overlooking the Pacific Ocean, lagoons, and esteros enclosed by sand dunes, rolling hills, and forests. begins with a stroll through eucalyptus, Cape ivy, vinca, Klamath weed Klamath weed
hypericumperforatum. , and broom, and every year it takes longer to get beyond the plant community I call "old ranchhouse."
Creatures that require a certain kind of vegetative vegetative /veg·e·ta·tive/ (vej?e-ta?tiv)
1. of, pertaining to, or characteristic of plants.
2. concerned with growth and nutrition, as opposed to reproduction.
3. architecture for forage and shelter find their lives disrupted by changes. Take the example of the California desert's wide-bodied lizard, unable to negotiate dense stands of the invasive Bromus rubens and consequently starving to death. Eucalyptus groves provide habitat for predators like the great horned owl great horned owl
Horned owl species (Bubo virginianus) that ranges from Arctic tree limits south to the Strait of Magellan. A powerful, mottled-brown predator, it is often more than 2 ft (60 cm) long, with a wingspan often approaching 80 in. (200 cm). , which preys on other owls. Diminished populations of the smaller saw-whet owl and others might be partly due to the unnatural advantage given to great horned owls by the increase in eucalyptus groves in the area.
Nutritional inferiority can be a subtle factor in the slow diminution of resources. In a study by Harold W. Avery, captive tortoises were provided either native or nonnative food. Those fed the native Camissonia boothii had a greater rate of protein assimilation and remained in positive nitrogen balance nitrogen balance
The difference between the amount of nitrogen taken into the body and the amount excreted or lost.
n throughout the study, whereas those fed Schismus barbatus, a non-native, experienced a significant loss in total body mass. Creatures may be seen eating nonnative plants, but their ability to thrive on such fare cannot be inferred.
Restoration begins at home
In informal observations of my employees, clients, and neighbors, I've noticed certain developmental steps once the interest in native plants quickens, potential pathways for the back-yard restoration gardener.
First, the gardener becomes aware of some part of the native flora, often spring wildflowers, that is visually appealing.
Planting annual wildflowers will in most cases lead to immediate success and pleasure. A tentative reach into other areas, such as shrubs and perennials, commences. More difficult subjects, such as challenging native grasses, and native trees, which require long-term involvement and delayed gratification, are subsequently tackled.
Somewhere in all this activity, the gardener notices that most of the work involved is weeding. The story of gardening is the story of weeds. Possibly unique to California is the extent to which these weeds are offered in nurseries, bought, and taken home by gardeners.
An ounce of prevention is worth a pound of cure, and a stitch in time
A new broom sweeps no good
A stand of French broom grows along the road to my house, between the road and the soccer field. Genista genista (jənĭs`tə): see broom. monspessulanis spreads rapidly, and its seed is said to live twenty-five to eighty years in the soil; it is adaptable to almost all habitats in the coast ranges, but its root system is usually shallow, and in wet or damp soil, seedlings can easily be pulled up. Every year it bloomed, sometimes twice, set seed, and ejected its seeds five to ten feet from each plant, spreading itself down the road.
One year some of us decided we didn't want to watch this increasing degradation of the land. We publicized a broom-removal day, borrowed weed wrenches and root jacks, put up signs, and met with lunches, children, and a willing spirit.
Along with publicity and support, we also received our share of letters criticizing our efforts. I read the letters at the chiropractor's office, where the strenuous activity had sent me. Although I ended up lying down, I didn't take those letters that way.
Some colleagues recommended ignoring these critics. I thought their feelings and attitudes needed to be considered, and I find that controversy, though not pleasant, forces me to continue investigations of these issues, to my own ultimate benefit. My search for the reasons to control biological invasions has taught me as much as any other part of my work.
I often hear the statement, "I'm not native here either." The hint of longing to belong somewhere rings a bell with me. Being not native here, does it not behoove be·hoove
v. be·hooved, be·hoov·ing, be·hooves
To be necessary or proper for: It behooves you at least to try.
To be necessary or proper. us to begin to know this land where we find ourselves, to honor it with a clear look rather than collude col·lude
intr.v. col·lud·ed, col·lud·ing, col·ludes
To act together secretly to achieve a fraudulent, illegal, or deceitful purpose; conspire. in its diminution?
We broom-pullers were mightily abused. We were called genocidal, racist, and, worst of all, "well-meaning." One of our critics extolled the beauty of wild lilac (Ceanothus ce·a·no·thus
Any of various shrubs or small trees of the genus Ceanothus, native mostly to western North America and having showy clusters of usually blue or whitish flowers. Also called redroot. ) blooming along the roadside, companioned by yellow broom. Ceanothus, in my experience, does not reseed Verb 1. reseed - seed again or anew
farming, husbandry, agriculture - the practice of cultivating the land or raising stock
seed - go to seed; shed seeds; "The dandelions went to seed"
2. into stands of broom, and since most ceanothus is relatively short-lived, in twenty to thirty years there will be no blue contrast to the ubiquitous yellow of broom blossoms.
Another argument goes something like this: Who are we to interfere with the dispersal of plant species, ongoing for eons? Who are we to make presumptuous pre·sump·tu·ous
Going beyond what is right or proper; excessively forward.
[Middle English, from Old French presumptueux, from Late Latin praes choices, favoring what we call native plants over the newcomers, which we ourselves also are. If broom plants outcompete natives, they say, it is interfering with evolution, the survival of the fittest, to remove broom.
This laissez-faire argument is called by one naturalist "letting your dog pee on a person after you've knocked him down." Does it make sense to maintain a hands-off posture in our wildlands, even as we see the plants we have introduced, and continue to introduce, move over the landscape like a conquering army, destroying food and shelter for those voiceless species we may not yet have heard from?
It may be that in a thousand years, broom and pampas grass will have found natural enemies, will have become part of the game instead of dominating it. By then, so many players will have been eliminated that it will be a much less interesting game.
In communities that border on open-space land or national or state park land, it is critical to educate gardeners. One lone gardener planting a hedge on the flanks of Mount Tamalpais created the vast stands of French broom now being expensively tackled by controlling agencies. The gypsy moth was introduced to the US to begin a silk-worm industry. European beach grass, now dominating a thousand-mile coast, was introduced to stabilize dunes. French and Scotch broom were introduced to stabilize old quarries. Kudzu kudzu (kd`z), plant of the family Leguminosae (pulse family), native to Japan. was brought in to revegetate re·veg·e·tate
v. re·veg·e·tat·ed, re·veg·e·tat·ing, re·veg·e·tates
To cause (eroded land, for example) to bear a new cover of vegetation.
v.intr. the South. Eucalyptus was brought in for firewood and lumber. Bermuda grass, kikuyu grass, and other weedy grasses were brought in as "miracle" lawns. Capeweed, iceplant, and Cape, Algerian, and English ivy were brought in as speedy ground covers. These disastrous introductions should influence future decisions about "the right plant for the job."
In many cases, native plants were rejected for these jobs. People want fast-growing hedges and screens, instant lawns, quick vines, and instant landscapes, and, in too many cases, the species that fall into those categories become invasive.
Gardening is supposed to be for pleasure, one of the few areas where choices can be made based on whim and personal preference, with no immediately apparent price to pay for casually made decisions. Gardeners may understandably resist limitations, given how few arenas are left to us where we can play without consequence.
We don't always know which species have the potential to become invasive. Showing restraint - resisting the plumelike flowers of pampas grass until we know for sure whether the supposedly non-invasive species really is so, forgoing the purple stalks of loosestrife loosestrife, common name for the Lythraceae, a widely distributed family of plants most abundant as woody shrubs in the American tropics but including also herbaceous species (chiefly of temperate zones) and some trees. until we are sure it will not invade in California the way it has in New England - doesn't seem much to ask.
Judith Larner Lowry is proprietor of Larner Seeds, which specializes in seeds of native plants of California. This article is excerpted from Gardening with a Wild Heart, available from Lamer Seeds, PO Box 407, Bolinas, CA 94924 and in better bookstores.