If you enjoy spending time outdoors in Missouri, knowing about the poisonous plants in Missouri is essential for your safety. These dangerous native species grow in woods, fields, and even your own backyard. Learning to identify them can help you avoid painful rashes, serious illness, or worse.
This guide will show you what these plants look like, where they lurk, and what to do if you come into contact with them. We’ll cover the big names and some lesser-known troublemakers. Let’s get started.
Poisonous Plants In Missouri – Dangerous Native Species
Missouri’s diverse landscapes are home to several plants that have developed potent defenses. These are not exotic invaders; they are native species that have grown here for centuries. Respecting and recognizing them is a key part of enjoying the state’s natural beauty safely.
1. Poison Ivy: The Notorious Itch
“Leaves of three, let it be.” You’ve probably heard that rhyme. Poison ivy is the most common cause of allergic skin reactions in the state. The oily resin, urushiol, binds to skin and causes a blistering, itchy rash.
Look for these features:
- Always has three leaflets per leaf.
- Leaf edges can be smooth, toothed, or lobed.
- Grows as a vine on trees or as a ground cover.
- In fall, leaves turn a bright red or orange.
- Can have white or greenish berries.
Remember, all parts of the plant—roots, stems, and leaves—contain urushiol year-round. Even dead vines can cause a reaction.
2. Poison Hemlock: The Deadly Lookalike
This plant is extremely toxic if ingested. Every part of poison hemlock is poisonous. It’s a biennial plant, often found in ditches, along roadsides, and in moist open areas.
Identification tips include:
- Tall, growing 3 to 8 feet high.
- Hollow stems with distinctive purple spots or blotches.
- Leaves are finely divided, resembling fern or carrot tops.
- Small white flowers grow in umbrella-shaped clusters.
- When crushed, it often smells musty or like mouse urine.
It’s crucial to note that poison hemlock looks similar to wild carrot (Queen Anne’s lace). Always check for those purple-spotted stems.
3. Water Hemlock: The Most Violent
Often considered North America’s most poisonous plant, water hemlock is found in wet habitats. It loves marshes, stream banks, and soggy meadows. Ingesting even a small amount of the root can be fatal.
Key identifiers are:
- Grows 2 to 6 feet tall.
- Stems are hairless and often have a purplish base.
- Leaves are compound with toothed leaflets.
- Clusters of small white flowers form umbrella shapes.
- The thick rootstalk has internal chambers that exude a yellowish, smelly oil when cut.
Never handle the roots of this plant. It’s danger is not just in eating it; the toxin can be absorbed through skin cuts.
4. Pokeweed: The Deceptive Berry Producer
Pokeweed is a large, perennial plant common in disturbed soils. While young leaves are sometimes boiled and eaten (with extreme caution), the rest of the plant—especially the roots and mature berries—is toxic.
You can recognize it by:
- Purple-red, smooth stems that can reach 10 feet.
- Large, lance-shaped leaves.
- Clusters of dark purple, almost black, berries that hang down.
- Bright pinkish-purple stems holding the berry clusters.
Birds eat the berries safely, but they are not safe for humans. Children are especially attracted to the colorful berries, so be vigilant.
5. Jimsonweed: The Hallucinogenic Hazard
Jimsonweed is a foul-smelling, large-leafed plant with a sinister history. All parts are poisonous, containing tropane alkaloids that cause severe anticholinergic syndrome.
Look for these distinctive traits:
- Large, trumpet-shaped white or purple flowers that open in the evening.
- Spiny seed pods that are egg-shaped.
- Large, irregularly toothed leaves.
- Can grow 3 to 5 feet tall and just as wide.
It’s often found in barnyards, waste areas, and along roads. The seeds are particularly potent, and intentional ingestion for psychoactive effects has lead to tragic consequences.
What to Do After Contact or Exposure
Acting quickly can minimize harm. Here are the steps to follow for different types of exposure.
For Skin Contact (Like Poison Ivy):
- Rinse the skin immediately with lukewarm water and soap. Use alcohol wipes if soap isn’t available.
- Scrub under fingernails to remove any trapped oil.
- Wash all clothing, shoes, and tools that may have touched the plant.
- Use calamine lotion or hydrocortisone cream to relieve itching later.
- See a doctor if the rash is widespread, on your face or genitals, or if you develop a fever.
For Suspected Ingestion:
- If someone has eaten part of a poisonous plant, do not wait for symptoms.
- Call the Missouri Poison Center immediately at 1-800-222-1222.
- Try to identify the plant. Take a photo or bring a sample if it is safe to do so.
- Do not induce vomiting unless instructed by a poison control expert.
- Follow their instructions precisely until help arrives.
Safety Tips for Gardeners and Hikers
Avoiding contact is always the best strategy. Here’s how you can stay safe while enjoying the outdoors.
- Learn the “big three” first: poison ivy, poison hemlock, and water hemlock.
- Wear long pants, long sleeves, and gloves when working in weedy areas.
- Teach children not to pick or eat any berries, roots, or leaves while playing outside.
- Keep your yard clear of pokeweed and jimsonweed, especially if you have pets or small children.
- When hiking, stay on cleared trails to minimize contact with undergrowth.
If you’re clearing land, never burn brush that might contain poison ivy. The urushiol can become airborne and cause severe lung irritation if inhaled.
Common Misidentifications to Avoid
Many harmless plants get mistaken for their dangerous cousins. Here’s a quick comparison to ease your mind.
Virginia Creeper vs. Poison Ivy: Virginia creeper has five leaflets, not three. It’s a common vine but is not poisonous, though it can cause mild stomach upset if eaten.
Wild Carrot vs. Poison Hemlock: Wild carrot (Queen Anne’s lace) has a hairy stem without purple spots. It often has a single dark purple flower in the center of its white bloom cluster.
Elderberry vs. Pokeweed: Elderberry berries grow in flat clusters, not hanging spikes. The plant is a shrub with woody stems, not the fleshy, purple stems of pokeweed.
FAQ: Your Questions Answered
What are the most common poisonous plants found in Missouri?
The most common you’ll encounter are poison ivy, poison hemlock, and pokeweed. They are widespread in both rural and urban settings.
Are there any dangerous plants in Missouri with berries?
Yes. Pokeweed has dark purple berries that are toxic. Moonseed vine and certain nightshades also have dangerous berries. A good rule is to never eat wild berries unless you are 100% certain of their identity.
How can I safely remove poisonous plants from my property?
Wear full protective clothing, including gloves you can discard or wash thoroughly. For small patches, carefully dig out the roots. For larger infestations, consider using a targeted herbicide according to label instructions. Never use a weed trimmer, as it can spray plant material.
What Missouri native plant causes a rash like poison ivy?
Besides poison ivy, some people may react to stinging nettle, which causes a temporary burning sensation, or wild parsnip, which can cause severe phytophotodermatitis (a blistering rash when skin exposed to the plant sap is then exposed to sunlight).
Can my pet be affected by these plants?
Dogs and cats can be affected, though they are less sensitive to poison ivy. They can, however, carry the oil on their fur and transfer it to you. More seriously, pets may ingest poisonous plants like hemlock or jimsonweed with severe consequences. Keep an eye on them during walks.
Living Safely with Native Flora
Missouri’s native plants form the foundation of its ecosystems, even the poisonous ones. The goal isn’t to eradicate them all but to coexist safely. By learning to identify these dangerous native species, you empower yourself to enjoy gardening, hiking, and exploring with confidence.
Keep this guide as a reference, and consider carrying a field guide on your outdoor adventures. A little knowledge goes a long way in preventing a painful or dangerous encounter with the poisonous plants in Missouri that share our environment.