As July winds down in the Puget Lowlands, there is good news and bad news. The berries are ripening on the native plants, but many of the flowers blooming are noxious weeds.
Noxious Weeds
In the public right-of-ways, vacant parcels, native growth protection areas, and other poorly managed lands, a legion of invasive plants produce flowers that uninformed citizens might call “wildflowers.” Below are a dozen “noxious weeds,” which I found recently along the Lowell Riverfront Trail. The direct quotes and information about biological control agents come from the Washington State University Integrated Weed Control Project. Other notes are based on Arthur Lee Jacobson’s Wild Plants of Greater Seattle, Ronald Taylor’s Northwest Weeds, or Turner and Gray’s Weeds of the Pacific Northwest.
Tansy Ragwort (Senecio jacobaea) – The Tansy Ragwort Flea Beetle has been a “highly successful biological control agent, repeatedly demonstrating outstanding control of tansy ragwort.”Purple Loosestrife (Lythrum salicaria) – “Purple loosestrife biomass at several sites in Washington and Oregon has been reduced by as much as 90%” using loosestrife beetles.Poison Hemlock (Conium maculatum) – The Poison Hemlock moth was accidentally introduced into the United States but is not a USDA approved biological control agent.Common Tansy (Tanacetum vulgare) – This plant was purposefully introduced by European colonists in the 1600s.Butterfly Bush (Buddleja davidii) – Tens of thousands of seeds have been counted from a single flower cluster.
St. John’s Wort (Hypericum perforatum) – Klamath Weed Beetles were one of the first biological control agents used in the United State.Creeping Thistle (Cirsium arvense) – With the Canada Thistle Stem Gall Fly, “strong grass competition in conjunction with good fly densities may reduce Canada thistle infestations.”Teasel (Dipsacus fullonum) – Growing up to nine feet tall, taproots can go down over two feet.Oxeye Daisy (Leucanthemum vulgare) needs sunshine and little else to thrive.Perennial Sowthistle (Sonchus arvensis) – I don’t know if this is the highly invasive Perennial Sowthistle or one of the less-invasive annual cowthistles.Wild Carrot (Daucus carota) has been called the “Devil’s Plague.”Old Man’s Beard (Clematis vitalba) grows rapidly, damages structures, weighs down trees, and shades out native plants.
Ripening Berries
I’m delighted by the berries ripening on the native plants, but I don’t eat them. I save them for the native animals, especially the fledgling birds, who need them more than I do. Also, there are more than a few ripening berries that are not safe to eat, including some of those shown below.
