Noxious Weeds
By Sandy Woods, Master Gardener
The simplest definition of a weed is "a plant growing where it is not
wanted.” Plants are called weeds when
they interfere with the intended use of land and water resources. For example, a dandelion may be a cultivated
salad green in a vegetable garden, but in a lawn it would be considered a weed.
A noxious or invasive weed is commonly defined as a plant that grows out of
place and is "competitive, persistent, and pernicious.” Legally, a noxious weed is any plant
designated by a Federal, State or County government as injurious to public
health, agriculture, recreation, wildlife or property. Noxious weeds common to San Luis Obispo
County include yellow starthistle, artichoke thistle, Arundo or giant reed,
cape ivy, French and Spanish Broom, barbed goatgrass and pampasgrass to name
only a few.
The continued spread of noxious weeds across the nation's open space is
reaching a crisis level. While many of
them are non natives, they are extremely competitive with our native plants as
they have adapted well to our climate but are not subject to their own natural
predators. As a result, millions of
acres of once healthy, productive rangelands, forestlands and riparian areas
have been overrun by noxious weeds. They
are invading recreation areas, parks, roadsides, stream banks, and private
lands. They destroy wildlife habitat,
reduce plant and animal diversity, reduce opportunities for recreational
activities, and cost millions of dollars in treatment and loss of productivity
to private land owners.
What can the home gardener do to help?
Educate yourself and help educate your friends and neighbors. Most people are not aware that they can
actually create or facilitate a new weed infestation. Noxious weeds can be spread into uninfested
areas through contaminated hay, seeds or nursery stock. Weed seeds can also become lodged into
vehicle tires and equipment, and then spread into new areas. There are also certain plants that are known
to be invasive that are still sold in nurseries. Ask your nursery if the landscape plants you
are purchasing could escape from your yard and create a problem for the
agricultural industry or the environment.
Or visit the UC website at http://wric.ucdavis.edu for online
information. Let us all do our part in
helping control this fast-growing environmental problem.