Poisonous plants in Texas deserve some attention so that necessary safety precautions are put in place. The same applies to poisonous flowers in Texas.

Poisonous Plants in Texas

In this article, we will outline various plants that are poisonous in Texas so that you know the plants to look out for and how you can possibly be safe around them.

A Comprehensive List of Poisonous Plants in Texas

Some of the poisonous plants in Texas are poison ivy, elephant ear, poison oak, poison hemlock, poison sumac, and Texas bull nettle. Sometimes, these are categorized as poisonous plants to touch in Texas. 

In this section, we will explore what you need to know about these poisonous plants, including their distinguishing characteristics, growing season and common pests. In some instances, we will also give you hints on the actions to take against the negative effects of these plants.

1. Poison Ivy

Poison Ivy

Growing season
  • Summer and spring
Distinguishing characteristics
  • Leaves grow in clusters of three, though they can be five at times
  • All leaves extend from one stem
  • Produces flowers that are greenish-white in spring and then berries that are white in fall
Growing conditions
  • Enjoys both full sun and shade
  • Acidic soils are preferable, especially those that do not contain phosphorus, selenium, and calcium
  • Loves higher temperatures
Common pests
  • Ants
  • Flies
  • Bees

The poison ivy can grow as a vine, tree, or small bush so it can be classified among poisonous shrubs in Texas. If you get into contact with this plant, you will begin to see small blisters and a rash that is itchy, within a minimum of 12 hours. One of the best interventions that you can use under such circumstances is washing the skin and then applying hydrocortisone. We suggest removing it as soon as possible, but be extra careful.

2. Poison Hemlock

Poison Hemlock

Growing season
  • Early spring
Distinguishing characteristics
  • Stems are hollow and have streaks and spots that are purple or reddish in color
  • Flowers grow in umbrella-shaped clusters and are white in color
  • Leaves have toothed edges and have a bright green color
Growing conditions
  • Needs considerable exposure to sunlight
  • Prefers soils that are moist
  • Seeds of the plant can germinate in temperature ranges between 60 and 80 degrees Fahrenheit
Common pests
  • Milkweed aphid, also known as Aphis asclepias
  • Honeysuckle aphid, also called Hyadaphis passerinii

This is one of the poisonous plants in Texas for dogs. Some of the symptoms of poison hemlock poisoning include vomiting and seizures. Unfortunately, there is no antidote for this type of poisoning, though the symptoms can be managed using various drugs that are recommended by health professionals. Therefore, we recommend that you remove the plant from your yard once you identify it. It might be a bit difficult to identify it because there are a few plants that look very similar to Poison Hemlock.

3. Texas Bull Nettle

Texas Bull Nettle

Growing season
  • Spring to mid-summer
Distinguishing characteristics
  • Has alternate leaves that are hairy
  • Produces five to seven white flowers
  • Grows up to three feet in height
Growing conditions
  • Thrives best under full sun
  • Loves loose soils that are well-draining
  • Grows in more humid climates 
Common pests
  • Weeds
  • Bacteria
  • Insects

The sap and hairy spikes that cover the leaves of these plants are the ones that trigger allergic reactions upon contact with your skin. If by any chance you touch the plant, you will experience a stinging sensation that will stick around for beyond an hour. 

To better manage the pain, you can use a homemade, cost-effective remedy that is made by mixing baking soda with water. Thoroughly mix the ingredients until a paste is formed and this can neutralize the acidic nature of the poison from the Texas bull nettle.

4. Poison Sumac

Poison Sumac

Growing season
  • Spring
Distinguishing characteristics
  • Produces clusters of light green or white berries
  • Has many stems where leaflets grow in clusters
  • Leaves have smooth edges, compared to those of the non-poisonous species
Growing conditions
  • Can survive under both full sun and shade
  • Grows soil such as loam or sand, with a capacity to hold water
Common pests
  • Aphids
  • Birds

The allergy symptoms that are caused by the poison sumac are similar to those that emanate from contact with the poison ivy. These include rash, blisters, and swelling. Immediately after contact has been established between the plant and your skin, use soap alongside large amounts of water to wash the affected area.

You can also apply hydrocortisone creams to alleviate the pain as you make arrangements to get professional medical attention.

5. Poison Oak

Poison Oak

Growing season
  • Between February and March
Distinguishing characteristics
  • Leaves appear like those of an oak
  • Has between seven and 13 leaflets that have pointed tips and smooth surfaces
  • Fruits are tan in color
Growing conditions
  • Full sun or partial shade
  • Easily grows on roadsides, abandoned land, or fields that are not yet cultivated
  • Can easily adapt to various moisture levels
Common pests
  • Birds
  • Some rodents

This plant harbors an oily substance that is called urushiol. This substance is responsible for the rash that is experienced by people who come into contact with the poison oak. It is also important to note that urushiol has long-lasting potency and that this substance can cling to pets or clothes, even up to a couple of months. 

The moment you get into contact with the poison oak, wash your skin using cold water and a string of soap, within a period of 10 minutes.

6. Water Hemlock

Water Hemlock

Growing season
  • Early spring
Distinguishing characteristics
  • Flowers grow in clusters that appear like umbrellas and they are white in color
  • Has a thick rootstalk that has a couple of small chambers
  • Mainly grows in wet and marshy spaces
Growing conditions
  • Partial sun, though it can adjust when exposed to full shade or direct sun
  • Grows in soils that are well-drained, organic and acidic, with uniform moisture
Common pests
  • Hemlock wooly adelgid
  • Carrot wasp
  • Red-shouldered pine beetles

The water hemlock belongs to the carrot family of plants. This plant has potent toxicity, to the extent that it can take a life in just 10 minutes of exposure to its poison. Just one fact to note – despite the extreme toxicity of the water hemlock, this plant has remarkable medicinal properties against intestinal worms, migraine headaches and pain that is associated with menstruation.


If you were wondering which poisonous plants grow in Texas, we have just comprehensively answered your question. Let’s go through a few reminders before you go:

  • Some of the poisonous plants that grow in Texas are the poison sumac, poison ivy, water hemlock and poison oak.
  • The symptoms that these plants cause vary from lighter rashes to seizures, while some, like the water hemlock, can even kill in just 10 minutes of contact.
  • Most of the plants that we discussed prefer full sun.
  • Some of the poisonous plants have medicinal properties for treating ailments such as migraine headaches.

We highly recommend that you exercise caution around the poisonous plants that we outlined in this article. Continue being a plant enthusiast but be sure to play it safe for yourself, as well as your pets and loved ones!


  • https://kingwood247er.com/poisonous-texas-plants/
  • https://www.baylor.edu/lakewaco_wetlands/index.php?id=34733
  • https://www.britannica.com/plant/poison-sumac
  • https://www.jstor.org/stable/3998628
  • https://www.jstor.org/stable/3998628
  • https://www.jstor.org/stable/3998628
  • https://www.maine.gov/dacf/mfs/forest_health/insects/hemlock_woolly_adelgid_fact_sheet.htm
  • https://uwm.edu/field-station/wildflower-watch-water-hemlock/\
  • https://www.webmd.com/vitamins/ai/ingredientmono-948/water-hemlock
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