Poisonous plants in Maryland is what can vary greatly and can be difficult to identify. With so many plant species in the state, it is essential to exercise caution when out in nature and to be able to recognize certain plants that can be quite dangerous.

Warning on the Poisonous Plants to Avoid Cultivating

This post contains a list of some of the most common poisonous plants that can be found in Maryland. You can find details about these plants below as you keep reading our guide.

List of Various Kinds of Poisonous Plants in Maryland

1. Poison Ivy

Growing Season
  • Spring
  • Summer
Leaf Shape Rounded
Specific Needs
  • Moist but well-drained soil
  • Partial shade or full sunlight
Common Pests
  • Beetles
  • Flies

Poison ivy is one of the toxic plants native to Maryland and other parts of eastern North America. It is often found in woodlands and margins, along with fences, roadsides, and even gardens, which means it is actively present is most places. Poison ivy contains an allergenic skin irritant called urushiol that causes the characteristic rash when it comes into contact with human skin, and the longer one is exposed to it, the more severe it becomes.

The Dangers of Poison Ivy

Symptoms can range from mild inflammation to severe blistering. However, localized reactions are common. People should always take precautions when handling or coming into close contact with poison ivy plants. Otherwise, treatment for the rash includes topical steroid creams and cool compresses in order to bring the itching down.

2. Poison Hemlock 

Poison Hemlock Poisonous Plants of Maryland

Growing Season All year round
Leaf Shape Triangular
Specific Needs
  • Moist soil
  • Part or full sunlight
Common Pests Aphids

Poison Hemlock or Conium Maculatum, is a highly poisonous biennial flowering herb native to Europe but has become widely naturalized in Maryland and other parts of the United States. All parts of the plant, including its white flowers, are highly toxic and may be fatal if ingested or absorbed through the skin, which means that you shouldn’t even touch or pick the flower. It could lead to sweating excessively, vomiting, dilated pupils, and even a high blood pressure.

 

In Maryland, it often grows on roadsides and in disturbed sites such as railroad tracks, abandoned fields, and wetlands. As a result, control should be attempted before the plant sets seed since seeds may remain viable for a long time. Management strategies include the careful removal of individual plants during dry conditions.

3. Poison Sumac

Maryland Poison Sumac

Growing Season
  • Summer
  • Spring
Leaf Shape
  • Pointy
  • Oval
Specific Needs
  • Flooded and marshy soils
  • Part or full sunlight
Common Pests
  • Aphids
  • Spider mites

Poison sumac, a highly poisonous plant native to North America, can be found in damp, low-lying habitats such as swamps, wet lands and even bogs throughout Maryland. When it comes to the features, the leaves of the plant contain a resin called urushiol, which is toxic to humans when touched or even inhaled the sap.

 

Symptoms of contact of this toxic plant would include redness, itching, blistering skin rashes, swelling, and infections from scratching the rash. It is important for people who spend time outdoors to learn how to identify poison sumac so that they can avoid contact with it, the easy way is to look out for the white berry one, because that is the toxic version. Appropriate protective clothing and gloves should also be worn.

4. Giant Hogweed 

Growing Season Spring
Leaf Shape Lobed
Specific Needs
  • Moist soil with good drainage
  • Full sunlight
Common Pests
  • Mealybugs
  • Spider mites

Giant Hogweed or Heracleum Mantegazzianum is a herbaceous, biennial plant native to Central Asia which has become increasingly established in Maryland. It typically grows four to five feet tall and is likely to produce large white flowers with many reddish-purple spots or streaks. One of the most distinctive features of this intoxicating plant is that it is deep-furrowed, bristly stemmed hollow stems which reach up to seven inches in diameter near their base.

The Risks of Giant Hogweed

How this is poisonous is through its sap, which would contain the toxic Psoralen compounds, and this can cause severe burns and blistering if it comes into contact with skin after exposure to sunlight; more extensive presence on the skin may also lead to permanent scarring and blindness.

5. Spotted Water Hemlock

Growing Season
  • Spring
  • Fall
Leaf Shape Lance-shaped
Specific Needs
  • Moist soil
  • Full shade tolerable
Common Pests
  • Aphids
  • Mealybugs

When the water hemlock has some spots or dots on it, then it is a highly poisonous plant species native to Maryland and the central and eastern United States. It can be found in wet areas such as marshes, shorelines, and meadows.

Properties of Spotted Water Hemlock

This wildflower is identifiable by its branchless stems with purple or white spots, leaves that are finely divided into threadlike segments, small clusters of white flowers on long stalks, and a large taproot that exudes an odor described as resembling parsnips or carrots, these are ways that you can simply identify them, and when you come across one, remember that it should never be ingested. Its toxic principles can affect the nervous system and cause tremors, seizures, comas, paralysis, or even death from respiratory failure.

6. Poison Oak

Growing Season Spring
Leaf Shape Rounded/irregular
Specific Needs
  • Full sunlight
  • Moist soil
Common Pests
  • Spider mites
  • Whiteflies

Poison oak is a poisonous plant that is not as famously found in Maryland and also in some parts of the Mid-Atlantic region of the United States. It is identified by its glossy leaves, which are typically composed of three smaller leaflets. On another note, it also has bigger leaves can appear shiny or velvety green in color, with prominent veins and dark red stems, which are poisonous too.

The Toxins in Poison Oak

If touched, it can cause intense dermatological reactions manifested as an itchy rash, inflammation, blistering, swelling, and sometimes serious infections if not treated promptly. Basically, different symptoms usually appear within one day of contact and last for about one week before resolving on their own.

7. Wild Parsnip

Growing Season Summer
Leaf Shape Diamond-like shape
Specific Needs
  • Moist to mesic soil
  • Partial or full sunlight
Common Pests Parsnip webworm

Wild parsnip is a poisonous plant native to temperate Eurasia, but it has become established in much of the United States, Canada, and parts of Europe. In Maryland, wild parsnip is among the weed species that are designated as invasive species.

Hazards of Wild Parsnip Plant

Notably, wild parsnip has toxic sap containing psoralen molecules which cause severe blistering reactions when it comes into contact with skin and through the eyes with they are exposed to the sunlight. Preventative measures should be taken against wild parsnip including avoiding handling the plant and wearing protective clothing.

8. Jimson Weed

Growing Season Spring
Leaf Shape Oval
Specific Needs
  • Full to partial sunlight
  • Acidic soil
Common Pests Beetles

Jimson weed is an annual, herbaceous plant native to tropical and subtropical regions which have naturalized over time in many parts of the United States. It is now commonly found throughout Maryland, particularly on agricultural land and roadsides, where they will grow and show themselves.

Poisonous Nature of Jimson Weed

This plant produces the alkaloids hyoscyamine and atropine, both of these compounds can be highly toxic when ingested or applied topically, which means neither touching it nor eating it is recommended. 

For this reason, individuals should wear gloves when handling Jimson weed and refrain from consuming it as its ingestion may result in serious side effects such as nausea, vomiting, delirium, rapid heart rate, paralysis, and even death.

Conclusion

There are various types of poisonous plants in Maryland as you have seen in this post and they thrive in different seasons. For example,

  • During the summer, keep a watch out for Poison Sumac, Wild Parsnip, and Poison Ivy.
  • You should avoid Spotted Water Hemlock throughout the fall season.
  • During the spring season, you can find Poison Sumac, Poison Ivy, Poison Oak, Spotted Water Hemlock, Jimson Weed, and Gian Hogweed.
  • In Maryland, only the Poison Hemlock plant may be seen growing all year.

We hope from now on, you will keep a safe distance from these plants to avoid any kind of danger.

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