Let us start off by saying this: most garden weeds are harmless in and of themselves. “Weed” is just a catch-all term we use for “plants that grow where we don’t want them.” They’re not to be confused with “invasives”, many of which humans do cultivate intentionally. Some weeds are however toxic or poisonous to humans and pets, and should be handled with care if we spot them in our gardens. For this blog, we’re going to offer a brief overview of common toxic garden weeds and poisonous plants and offer some ideas and resources for eliminating them. Let’s dig in!
A Quick Note: We’re gardeners, not botanists or poison control specialists, and this blog is meant to be informative but not definitive. Please do not consume any plant you haven’t had professionally identified, and when in doubt contact poison control or local emergency services.
Common Toxic or Poisonous Weeds
This list is by no means all-encompassing—there are plenty more garden weeds that can dangerous to people and pets. It’s just a list of the more common ones found around the North America. If you’re concerned about local toxic weeds in your garden, talk to your local cooperative extension, garden club, or fish and wildlife service for region-specific information.
And now, some common toxic or poisonous weeds:
· Poison Ivy, Poison Oak, and Poison Sumac: While these are three different species, they carry the same reactive chemical compound (urushiol) that causes ugly and painful rashes in humans and animals. They’re easy to identify—we have a whole blog about them here—and while they’re not overly-common in cultivated spaces birds do love eating the seeds and spreading these plants far and wide. Learn how to spot them and what to do about them to keep your garden space safer and happier for everyone involved!
· Giant Hogweed (Heracleum mantegazzianium): Giant Hogweed has been the subject of much discussion in gardening, agricultural, and conservation circles recently, and with good cause. This Eurasian invasive not only crowds out native plant life, but contains a sap that cause chemical burns when activated by exposure to sunlight. The results for both humans and animals can vary from skin irritation to permanent scarring or, if the sap gets in the eyes, temporary or permanent blindness. Fond of moist, sunny places and capable of growing 10 to 15 feet/3 to 7 meters tall, Giant Hogweed is at least easy to spot. Should we find it in our gardens or yard spaces, the best approach is to seek professional guidance from your local cooperative extension or another specialized service and do not attempt to remove it yourself.
· Carolina Nightshade (Solanum carolinense): This plant goes by many names, including Carolina nightshade, Carolina horsenettle, horsenettle, bull-nettle, and wild tomato. The latter indicates a common problem: as a member of the Solanaceae or nightshade family, Carolina nightshade is a relative of the cultivated tomato and a cousin to peppers and eggplants. While it bears some resemblance to its domesticated relatives, this plant is not at all safe for human consumption. Symptoms of consumption may include fever, headache, throat irritation, nausea, vomiting and diarrhea. The good news is that it’s relatively safe to handle, although we should wear gloves while weeding it to protect our hands from the spiky stems. Weeded Carolina nightshade does not belong in a compost heap; the seeds inside its berries are hardy and composted Solanum carolinese will likely reappear in the compost next season.
· Datura stramonium: We’ll lead with this plant’s scientific binomial, as it has far too many common names to count. You may know it as devil’s trumpet, jimson weed, moon flower, thorn apple, or just datura. Another member of the Solanaceae family, D. stramonium is often used a garden or landscaping plant due to its beautiful, fragrant, trumpet-shaped flowers. The blooms open at night to release their scent, hence the occasional name “moonflower”. Birds spread the seeds—which fall from spikey ball-shaped fruit, hence “thorn apple”—and therein lies the problem. Datura stramonium can and will pop up in unexpected places. We can speak from experience, as we’ve seen this plant appear in the Gardzen Test Gardens when the nearest known specimen is over a mile away. While it’s generally considered safe to handle—wear gloves to avoid the thorns—all parts of the plant contain a number of toxic alkaloids, and ingestion may result in nightmarish hallucinations, muscle paralysis, suffocation, and death. Be careful around this plant and if there’s a chance a person or pet has consumed any part of it seek emergency medical care immediately!
Awareness, Not Fear
We shouldn’t be afraid of these plants, nor any others. Rather, we should recognize them for what they are and treat them with awareness and respect. There are no bad plants, just plants growing where we don’t want them to and plants that humans should be cautious with. By learning a bit more about the toxic or poisonous weeds that may appear in our gardens, we can both be safer and enjoy gardening and nature in a new way. Gardens are part of the wide natural world, and that includes some occasionally exciting visitors like these!
If you have tips or tricks for dealing with poisonous/toxic weeds—or a particularly pernicious weed that you’d like to discuss—let us know in the comments or via email. Gardzen is all about community and we love to hear from you!
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