When you’re gardening or hiking in the Old Line State, it’s important to know about the poisonous plants in Maryland. Several common ornamental plants found in Maryland gardens contain toxins that can pose risks to people and pets. This guide will help you identify these plants, understand the symptoms they cause, and learn what to do if exposure occurs.
Knowledge is your best defense. Many of these plants are beautiful and widespread, making them easy to encounter by accident.
We’ll cover everything from common backyard dangers to wild species found in state parks. Let’s get started.
Poisonous Plants In Maryland
This section provides a detailed overview of the most significant toxic plants across the state. We’ve grouped them to help you learn about them more easily.
Common Ornamental Garden Plants With Hidden Dangers
Many plants sold at local nurseries can be harmful. They are popular for their looks and hardiness, but their toxicity is often overlooked.
Oleander (Nerium oleander)
Oleander is a popular evergreen shrub with showy flowers. Every part of this plant is extremely toxic.
- Identification: Long, narrow dark green leaves with clusters of white, pink, or red flowers.
- Toxin: Cardiac glycosides, which affect the heart.
- Symptoms: Nausea, vomiting, abdominal pain, irregular heartbeat, and can be fatal.
- Note: Even inhaling smoke from burning oleander or using its sticks for food skewers is dangerous.
Foxglove (Digitalis purpurea)
Foxglove is a tall, striking plant with bell-shaped flowers. It is the source of the heart medicine digitalis, but in its raw form, it is poisonous.
- Identification: Tall spikes with tubular purple, pink, or white flowers spotted inside.
- Toxin: Cardiac glycosides.
- Symptoms: Similar to oleander: severe stomach upset, confusion, vision problems, and heart rhythm disturbances.
Autumn Crocus (Colchicum autumnale)
Not to be confused with the spring crocus, this plant blooms in fall. It is highly toxic and sometimes mistaken for wild garlic.
- Identification: Pale purple flowers that appear in autumn without any leaves present.
- Toxin: Colchicine, a potent alkaloid.
- Symptoms: Severe vomiting, diarrhea, organ failure, and can be fatal even from a small ingestion.
Daffodils (Narcissus spp.)
These cheerful spring bloomers have toxic bulbs, which can be mistaken for onions.
- Identification: Yellow or white trumpet-shaped flowers on a single stem.
- Toxin: Lycorine and other alkaloids, concentrated in the bulb.
- Symptoms: Nausea, vomiting, diarrhea, and tremors if ingested in large amounts.
Native And Invasive Woodland Poisonous Plants
Maryland’s forests and trails are home to several native toxic species. Being able to identify these is crucial for hikers and foragers.
Poison Ivy (Toxicodendron radicans)
This is perhaps the most well-known problematic plant in the region. It causes an itchy, blistering rash upon contact.
- Identification: Remember “Leaves of three, let it be.” Leaves are shiny or dull, with smooth or notched edges. It can grow as a vine, shrub, or ground cover.
- Toxin: Urushiol, an oily resin that binds to skin.
- Symptoms: Red, itchy rash, often with linear blisters, appearing 12-72 hours after contact.
Poison Hemlock (Conium maculatum)
This is a highly toxic invasive biennial that grows in wet areas like ditches and stream banks.
- Identification: Tall plant (up to 8 feet) with hollow, purple-spotted stems and fern-like leaves. Smells musty or like mouse urine.
- Toxin: Coniine and other pyridine alkaloids.
- Symptoms: Nervous system effects including tremors, salivation, dilated pupils, rapid heartbeat, and potentially fatal respiratory failure.
Pokeweed (Phytolacca americana)
This common native plant has berries that are attractive to birds but toxic to humans. Young leaves are sometimes foraged but must be boiled multiple times to be safe.
- Identification: Large plant with red-purple stems, large leaves, and hanging clusters of dark purple berries.
- Toxin: Phytolaccatoxin and phytolaccigenin in roots, berries, and leaves.
- Symptoms: Severe stomach cramps, vomiting, diarrhea, and can slow breathing and heart rate.
Houseplants And Holiday Plants Of Concern
Toxicity isn’t limited to the outdoors. Many common houseplants can also pose a risk, especially to curious pets and children.
Peace Lily (Spathiphyllum spp.)
A popular low-light houseplant, it contains calcium oxalate crystals.
- Symptoms: Intense burning and irritation of the mouth, lips, and tongue, excessive drooling, and difficulty swallowing. It is generally not life-threatening but very uncomfortable.
Poinsettia (Euphorbia pulcherrima)
Its toxicity is often exaggerated, but it can still cause irritation.
- Symptoms: Mild nausea or skin/eye irritation from the milky sap. It is considered low in toxicity but best kept out of reach.
English Ivy (Hedera helix)
Common as both a ground cover outdoors and a hanging houseplant.
- Toxin: Triterpenoid saponins.
- Symptoms: Stomach upset, excessive drooling, and abdominal pain if ingested in quantity.
Recognizing Symptoms Of Plant Poisoning
Symptoms vary widely depending on the plant, the amount ingested, and the person’s age or size. Here are the general categories of reactions to watch for.
Gastrointestinal Symptoms
These are the most common signs of plant poisoning and often appear first.
- Nausea and vomiting
- Diarrhea or abdominal cramps
- Excessive drooling (especially in pets)
Dermatological Symptoms (Skin Reactions)
These occur from contact with plants like poison ivy or from handling others.
- Itching, redness, and rash
- Blisters or weeping sores
- Swelling or burning sensation
Neurological And Cardiac Symptoms
These are signs of more serious poisoning and require immediate medical attention.
- Dizziness, confusion, or headache
- Tremors, seizures, or weakness
- Irregular heartbeat or changes in blood pressure
- Dilated pupils or vision changes
Immediate First Aid Steps For Exposure
If you suspect contact with or ingestion of a poisonous plant, act quickly and calmly. Follow these steps.
- For Skin Contact (e.g., Poison Ivy): Immediately rinse the skin with lukewarm water and soap. Wash under nails and any clothing that may have touched the plant. Rubbing alcohol can help remove the oils if used promptly.
- For Eye Exposure: Rinse the eye gently with lukewarm water for 10-15 minutes. Seek medical advice.
- For Ingestion: Remove any plant material from the mouth. Rinse the mouth with water. Do not induce vomiting unless instructed by a poison control expert.
- Call for Help: Contact the Poison Control Center at 1-800-222-1222 immediately. They provide free, expert guidance 24/7.
- Gather Information: If possible, identify the plant. Take a photo or bring a sample (safely contained) to help with identification. Note how much was ingested and when.
- Go to the ER: If the person is having trouble breathing, seizures, or is unconscious, call 911 or go to the nearest emergency room immediately.
Protecting Children And Pets In Your Yard
Creating a safe outdoor space requires proactive planning. Here are practical tips.
Audit Your Garden
Walk through your property and identify all plants. Use a plant identification app or consult with a local nursery or extension service if you’re unsure.
Consider Removal Or Barriers
For highly toxic plants like oleander or foxglove, consider removing them, especially if you have young children or pets that chew on things. Alternatively, install secure fencing or raised beds to block access.
Supervise And Educate
Teach children not to put any part of a plant in their mouth. Supervise young children and pets closely when they are in areas with unknown plants.
Choose Safe Alternatives
When planting new gardens, opt for non-toxic species. The Maryland Cooperative Extension offers lists of safe and native plants suitable for local landscapes.
Safe Foraging Practices In Maryland
Foraging for wild edibles is popular, but it comes with risks. Mistaking a toxic plant for an edible one is a common cause of poisoning.
- Never Assume: Positive identification is required. Many edible plants have poisonous look-alikes (e.g., wild carrot vs. poison hemlock).
- Use Multiple Guides: Cross-reference with a reliable field guide and a local expert. Don’t rely on a single app photo.
- Start with Obvious Plants: Begin by foraging easily identifiable plants like blackberries or dandelions before moving to more challenging species.
- Test a Small Amount: Even with a correctly identified edible plant, try a tiny amount first to ensure you don’t have a personal allergic reaction.
Resources For Maryland Residents
You don’t have to figure this out alone. Maryland has excellent local resources.
University of Maryland Extension Service
This is a premier resource. They offer plant identification services, fact sheets on toxic plants, and advice on safe gardening.
Maryland Poison Center
Located at the University of Maryland School of Pharmacy, they are your 24/7 lifeline. Save their number: 1-800-222-1222.
Local Nurseries And Arboretums
Places like the Ladew Topiary Gardens or the Adkins Arboretum can be great places to learn about plant identification in a controlled setting.
Frequently Asked Questions
What is the most dangerous poisonous plant in Maryland?
Poison hemlock and water hemlock are among the most dangerous due to their potent neurotoxins, which can be fatal even in small amounts. All parts of the oleander plant are also extremely toxic.
Are azaleas and rhododendrons poisonous in Maryland?
Yes. Plants in the Rhododendron genus, which includes azaleas, contain grayanotoxins. Ingestion can cause vomiting, drooling, and in severe cases, coma or cardiovascular collapse. They are common in Maryland landscapes.
What should I do if my dog eats a poisonous plant?
Stay calm. Remove any plant material from their mouth. Call your veterinarian or the ASPCA Animal Poison Control Center (888-426-4435) immediately. Do not wait for symptoms to appear, as early intervention is key.
How can I safely remove poison ivy from my property?
Wear long sleeves, pants, gloves, and boots. Carefully dig out the entire root system. Do not burn it, as inhaling the smoke can cause severe lung irritation. Place all plant material in heavy-duty trash bags for disposal.
Where can I get a plant identified in Maryland?
You can submit photos to the University of Maryland Extension’s Home and Garden Information Center. Many county extension offices also offer plant identification services to residents.
Staying informed about poisonous plants in Maryland empowers you to enjoy the state’s natural beauty safely. By learning to identify key threats, practicing caution in the garden and woods, and knowing who to call in an emergency, you can significantly reduce the risks for yourself, your family, and your pets. Always err on the side of caution—if you’re unsure about a plant, it’s best to avoid it.