You may have seen the buzz around the internet and even on local posts about the poisonous and toxic weeds that are becoming more prevalent. This is, in fact, true. They are growing everywhere. Why now?
Most weeds are perfectly suited to life on disturbed soils. Modern construction and subdivisions favor the stripped-earth method, which leaves many square feet of soil in every new development bare, just waiting for weeds to move in.
Frequently, weeds tolerate inconsistent moisture and are somewhat drought tolerant. Their seeds are attractive to birds, which have digestive systems that don't seem to be affected by their toxicity. It’s the perfect recipe for a plethora of “never seen that before” weeds.
The two I am seeing most on social media are poison hemlock (Conium maculatum) and two varieties of nightshade: deadly (Atropa belladonna) and bittersweet (Solanum dulcamara). These are, historically, both medicinal and deadly.
This toxic weed is a biennial, though in our mild climate it is frequently found as a perennial (depending on location and intensity of winter). It closely resembles Queen Anne’s lace or carrots, especially as a seedling. By the second year, a 6- to 8-foot-tall plant can produce up to 38,000 seeds, which can lie dormant for up to six years.
All parts of the plant are highly toxic to humans, pets and livestock.
Poisoning occurs when poison hemlock is misidentified by foragers for wild parsnips, parsley or anise. Whistles made from hollow stems of poison hemlock have caused death in children. Note that the stems can remain toxic for three years after they have died back.
Ingestion can cause stomach pain, vomiting and progressive paralysis of the central nervous system; ingestion of more than six to eight fresh leaves, or even smaller doses of the seeds and roots, can be fatal for adults.
Poison hemlock identification is easy.
One characteristic is its spectacular size, while Queen Anne’s lace has a similar bloom but is just 2 feet tall. Large maroon blotches on the stems are the second most notable feature of poison hemlock. The plant also has a very deep, vertical taproot.
The safest time to remove poison hemlock is in the first year, when the plants are significantly less toxic. They look like carrots but if you didn’t plant seeds where you found them, they are probably not carrots. Allowing them to grow, thinking they may be wild parsnips or carrots, is not a good idea.
Digging to extract the entire root is preferred and much easier to accomplish when the plant is small. Removal after the plant has fully matured becomes a much bigger task.
Livestock are particularly vulnerable to this plant, and the most common accidental ingestion occurs when poison hemlock is unknowingly harvested with feedstocks.
Learn more about poison hemlock at https://bit.ly/3Ts40Oa.
Pretty purple flowers on a stout vigorous stem dangle temptingly through the fence. Sweet, shiny black berries beg to be savored. Hello, deadly nightshade, not so happy to meet you.
Honey produced by bees who have been pollinating deadly nightshade flowers will kill you. This is the most toxic member of the Solanaceae family, which also includes a slightly less toxic variety, bittersweet nightshade.
Nightshades include everyday refrigerator inhabitants such as peppers, tomatoes and potatoes; those with sensitivity to the edible versions avoid them altogether.
Bittersweet nightshade is a climbing sturdy vine that grows up to 30 feet or more and into trees and shrubbery, spreading vigorously with root-suckering shoots.
Deadly nightshade tends to have a more bushy growth habit, being 3 feet to 4 feet in size and height.
Leaves and fruit for deadly and bittersweet nightshade have different levels of toxicity depending on growth stage, soil and light. Berries and blooms are simultaneous, producing about 30 seeds, which birds ingest and spread. All parts of both plants are toxic to humans, pets and livestock.
Bittersweet nightshade has red, attractive berries that have an unpleasant flavor, but is followed by a sweet taste, making them tempting to try.
Find more on bittersweet nightshade at https://bit.ly/4vOHblr.
For details on deadly nightshade, go to thespruce.com and type deadly nightshade into the search window.
When removing any toxic plant, protective clothing should always be worn, including long sleeves, long pants and gloves. Face protection and goggles, potentially even a respirator, also are necessary as airborne contact has been an issue for some. The toxic plant should not be placed in your compost bin or in your yard waste toter. It should be bagged and placed into your landfill trash tote.
Remove your clothing and wash them separately. Taking a thorough shower to remove any traces of the plant from your skin is recommended. Disinfect your tools with a bleach solution and/or allow them to dry thoroughly in the sun. If you get any re-growth, use a herbicide (follow instructions carefully) to treat the sprouts.
Pictures included with this column show what the plants look like this time of year. Identifying them to mitigate their impact in your yard is important. While you may not be able to remove an entire plant this summer, cutting it to the ground to eliminate further seed development will help prevent the spread of seeds in your yard and into neighboring spaces. Be sure to mark where the plant was so that you don’t forget to complete the removal later.
The Washington State Weed Control Board offers a guideline to noxious weed removal at nwcb.wa.gov/control-and-disposal.
Kelle Rankin-Sunter is founder of Blaine CORE, which holds free home and gardening classes at Blaine Public Library. Rankin-Sunter can be reached at fruit@Blaine-CORE.com.
