The Deadliest Plant In The U.S. That Every Homeowner Should Know About

Depending on where you live in the United States, you might keep an eye out for particular poisonous plants — wild poinsettia in the South, pokeweed in the East, or Jack-in-the-pulpit in damp woodland areas. These plants pose little danger unless ingested, and they're distinct enough to identify and avoid. However, not all poisonous plants are so easy to spot.

Across the U.S., homeowners should keep an eye out for water hemlock. Two species of this deadly plant thrive in North America, with spotted water hemlock (Cicuta maculata) found across the continental U.S. and western water hemlock (Cicuta douglasii) found in northwestern states like Oregon. Water hemlock is a member of the parsley family, which sounds innocent enough, but it is the most toxic plant in the country and potentially fatal when ingested by humans and many animals. Unfortunately, it looks almost indistinguishable from wild carrot, also known as Queen Anne's lace (Daucus carota), and yarrow (Achillea millefolium), both of which are often foraged by natural foodies. While it is often difficult to tell the difference between common edible plants and poisonous look-alikes, it is not impossible, allowing you to safely identify and remove an unwelcome invader like water hemlock.

As a member of the Apiaceae family, when water hemlock is not blooming, its many-leafed stalks may resemble those of edible plants, but you shouldn't garnish your dinner with it. Water hemlock can be found in a variety of environments, namely ones that are either saturated with water, such as freshwater swamps, marshes, and floodplains, or near water sources like rivers. Look for it in areas of your yard that remain moist or hold standing water after it rains. The plant, which can reach 8 feet tall, has smooth stems and tapered leaves, and its stalks sprout white inflorescences, or clusters of small flowers.

Water hemlock's white flowers are similar to those of Queen Anne's lace and yarrow, but Queen Anne's lace is shorter, with hairy stems, while yarrow's flowers grow closer together and its leaves appear more feathery. The most common form of water hemlock in North America, spotted water hemlock, also resembles the elderberry plant (Sambucus nigra) and can be found growing alongside it, but though they look alike, the plants are quite different. Water hemlock is an herbaceous, slender plant with stems and nodes, while elderberries are shrubs with bark. Though poisonous plants might look beautiful in your garden, it's best to remove them for the safety of your family and pets.

Though water hemlock is not dangerous to touch, it is best to wear gloves and fully cover your skin before tackling the removal process, as the sap contains phototoxic compounds that lead to sun sensitivity and blisters. If you have only found one or two water hemlock plants, you can dig them up to prevent them from flourishing, or you can utilize herbicides to kill them. Glyphosate has been shown to be effective on plants growing above the water line, but it does not work well if the plant is growing from a body of water or a submerged area of land. Another herbicide option is a compound of 2, 4-D, which kills the plant systemically from within. When using aquatic herbicides like 2, 4-D, be mindful of water restrictions or local wildlife.

If you decide herbicides are the best choice for you, consider the different types of weed killer before spraying your yard. Though you can handle a small patch of water hemlock on your own, if the patch is large or begins to spread, it might be best to discuss your options with a weed control expert.