Controlling Scotch Broom
Scotch broom is a large shrub bearing flowers and flat pods that indicate its affiliation with the pea family.
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By Maureen Gilmer
DIY--Do It Yourself Network
They say the only real winners in the California gold rush were the guys who sold the shovels. Correction--the guys who sold the shovels and the whiskey.
It is this human desire for inebriation that may explain how Scotch broom made it across the Atlantic and all of North America to the Mother Lode. Most references say it was introduced as an erosion control plant for coastal conditions. In its homeland, broom thrives in the maritime climate. Other books tell us broom arrived as a Victorian garden ornamental.
But the Sierra Nevada is far from the coast, almost to the Nevada border as the crow flies. Few of those tearing up the land for yellow metal were concerned about land restoration. Most miners panned for gold knee deep in icy streams and knew bone-chilling pain. In winter they experienced real suffering. Whiskey was the drug of choice for self-medication, and if a week's work could buy a can of peaches or a bottle of rye, the choice was obvious.
How many cases of Scotch whiskey made it to the Mother Lode no one can say. We do know that those precious bottles had to be packed in something. Cheap, springy and readily available, bundles of fresh cut broom were the bubble wrap of the 19th century. In every gold camp from Sonora to Sierra City, cases of imported whiskey were opened and the broom packing discarded. It is at these points that the broom invasion likely began.
Scotch broom (Cytisus scoparius) is a large shrub bearing flowers and flat pods that indicate its affiliation with the pea family. Seed pods still attached to the packing material could sprout with the winter rains or lie dormant for up to 30 years. Plants that had supplied Europe with sweeping brooms naturalized in the west and spread like wildfire. You can literally chart the location of every gold-rush settlement by the presence of broom colonies, which remain to this day.
This species is intensely beautiful in bloom but is nearly leafless on green stems the rest of the year. The tiny leaves are borne on stiff straight sticks that make wonderful brooms. But it was a hand-held whisk broom known as a "bisom" that made the plants essential to the baker's craft. In the days of brick ovens, the cooking surface had to be swept out between bread bakings. Dry broom would ignite immediately. Green broom bisom dipped in water resisted burning long enough to do the job. Clearly a baker required a good deal of living broom growing nearby to ensure a plentiful supply. So did the whiskey shipper.
Today there is a great struggle to stop the steady advance of broom. Aided by runoff, animals and even insects, broom's encroachment is alarmingly rapid where conditions are right. For homeowners in these areas, broom can disfigure surrounding wild lands, resulting in a monoculture. Wild plants distributing seed into the cultivated landscapes make it a pernicious weed.
Control can be as seriously challenging because there are no simple solutions. Physical removal--simply pulling or grubbing out--will eliminate plants, but the soil disturbance can result in a plethora of new seedlings. Fortunately, seedlings are easy to pull while still young. Programs of biological controls have introduced a stem miner and seed beetle with limited success. Goats have proved more effective but require direct management. Herbicides such as Roundup have been widely used, but toxicity, particularly in wildland ecosystems, creates a new set of challenges. An integrated approach of all three methods is being applied in much of California.
Scotch broom is a true "planta non grata" in the West. If it encroaches onto your property or landscape, make eradication a priority. And listen to your mother when she says drinking isn't a good idea. If miners had been bigger on sobriety, the broom would have thankfully stayed home.
Invasive Plants of California's Wildlands is perhaps the best work on the subject. It is applicable to much of the United States as well. Detailed background on plants, threats and eradication measures are discussed at length in language homeowners can understand. Helpful color photography and detailed drawings makes plant ID foolproof.
Invasive Plants of California's Wildlands (University of California Press 2000), edited by Bossard, Randall and Hoshovsky.
(Maureen Gilmer is a horticulturist and host of "Weekend Gardening" on DIY-Do It Yourself Network. E-mail her at firstname.lastname@example.org. For more information, visit : www.moplants.com or : www.DIYNetwork.com. Distributed by Scripps Howard News Service.)