How to Remove Poison Sumac From Your Garden

Poison oak with its leaves of 3 and light-colored berries.

Joe DiTomaso / Design Pics / Getty Images

Poison sumac (or Rhus vernix) grows in damp and swampy wooded areas in the Southeast and in some pockets of the northeastern U.S. The Rhus genus (which also includes poison ivy and poison oak) is native to North America and is sometimes classified as "Toxicodendron," rather than "Rhus, " meaning "poison tree" in Greek. If you find this plant on your property, you'll want to get rid of it to avoid contracting an itchy and debilitating rash.

But, what makes this plant so poisonous?

The answer lies in the sap—called urushiol—that runs through all parts of the plant. Any exposed part of your body that grazes against poison sumac releases this oil. Complicating matters further, the contact doesn't have to be direct. For example, a dog that runs through a patch of poison sumac can transfer the oils from its fur to your skin, resulting in a rash. The poison can also be brought inside on clothing and gloves, making decontamination important should you be eradicating it or working alongside it.

Identifying Poison Sumac

Poison sumac is more difficult to identify than its three-leafed cousins, poison ivy and poison oak. Poison sumac has at least five, and up to 13, leaves on each stem. The plant's stems are characteristically red and its leaves are green in the summer and colorful (ranging from yellow to red) in the fall. The leaves of this poison plant are smooth around the edges, rather than jagged, and its old bark appears rough. Poison sumac can be identified by its green berries that turn white in the fall and grow in small clusters on individual stems

When to Remove Poison Sumac From Your Garden

Poison sumac is at its prime late spring to mid-summer when the plant is in full bloom. And while there is no totally "safe" time to eradicate this poison, the best time go at it is in the winter or in early spring, before the last frost. During this time, the plant contains the least amount of urushiol. Even so, you must wear protective clothing, tuck your pants into your socks, and tuck your sleeves into your gloves before proceeding.

What You'll Need

Equipment/Tools

  • Protective clothing
  • Rubber gloves
  • Boots
  • Shovel
  • Pruning shears

Materials

  • Flattened cardboard or tarps
  • Mulch
  • Trash bags
  • Pump sprayer
  • Herbicide

Instructions

Removing Poison Sumac by the Roots

One organic method used to get rid of poison sumac is to pull it out by the roots. The roots must be disposed of in the trash.

Project Metrics

  • Working Time: 1 to 2 hours, depending on the level of infestation
  • Total Time: Up to 1 year

Warning

Do not burn poison sumac clippings! Inhaling fumes from burning any poisonous plant causes far greater health problems than the rash caused by skin contact.

  1. Pull the plant from surrounding growth and structures and trim it back to the ground with pruning shears. If the bush is old, its vines could be intertwined with structures nearby. Use your shears to free it, and then bag all the clippings.
  2. Spray the surrounding area with a hose to saturate the soil. Wait about 30 to 60 minutes to allow the water to soak in, making it easier to pull up the roots.
  3. Using a shovel, dig around the root ball, prying it up from underneath. Then, with gloved hands, pull all the roots from the soil and place them in a plastic garbage bag.

Smothering Poison Sumac

Smothering entails cutting the sumac plants close to the ground and then placing newspaper, cardboard, old carpeting, or tarps on top. However, even after you kill poison sumac plants, they remain toxic. So, be careful when disposing of the plant and its roots after pulling back the smothering agent.

Project Metrics

  • Working Time: 1 to 2 hours, depending on the level of infestation
  • Total Time: Up to 1 year
  • Material Cost: Under 10 dollars
  1. Using pruning shears, trim the plants to the ground. Discard the trimmings in a plastic garbage bag.
  2. Next, take cardboard or a tarp and cover the ground where the plant once lived. Take care to cover the outlying areas where roots could throw up additional vines. Spread mulch over the cardboard or tarp and let it sit for at least one season.
  3. After at least one growing season has passed, uncover the cardboard or tarp and dig up the roots using the same precautions you would for live plants. Discard them in a plastic garbage bag.

Remove Sumac Using Herbicides

As a last resort, you can use herbicides to effectively get rid of any poison plant. Roundup spray is a popular option, but the controversial use of glyphosate-based herbicide can cause toxic backlash to your local environment. Another widely available herbicide is Ortho Brush-B-Gon, which is triclopyr-based. These products kill a great variety of invasive plants, making them not only effective on poison sumac, but also on less bothersome weeds.

Project Metrics

  • Working Time: 1 hour
  • Total Time: Up to 2 weeks
  • Material Cost: Under 50 dollars
  1. Herbicide eradication works best on sunny, calm days with little wind. You also want to make sure there is no rain in the forecast that will wash off the chemical before it kills the plant. Don't spray if rain is predicted at any time within 24 hours of treatment.
  2. Mix the herbicide with water, according to the package directions, inside of a pressurized tank sprayer like a pump sprayer.
  3. Spray the plants when they are fully leafed out. This means, going after the culprit during the height of its growing season. Apply heavy spray to plants growing on the ground or on a wall. If sumac vines have engulfed a tree, "paint" the herbicide onto the leaves to avoid damaging the tree with overspray.

Poison Sumac Removal Tips

Once eradication is done, spray down your boots and gloves with a strong stream from the garden hose. Take off your clothing and place it directly in the washing machine, add detergent, and then cycle on "hot." Shower and use soap and shampoo to wash your entire body and hair.

If you're using an herbicide, understand that its use may also kill your coveted plants. So, don't spray an herbicide anywhere near your perennial or vegetable garden. In fact, vegetables or herbs could fall victim to overspray, making them harmful for consumption.

Lastly, no matter what method is used, removal may have to be performed more than once to achieve complete success.

Treating Poison Sumac

If poison sumac touches your skin during the eradication process, apply rubbing alcohol to the infected area, and then rinse thoroughly with water. This action removes the urushiol before it takes effect. However, once the rash appears, treating poison sumac is similar to treating a poison ivy rash. Some people obtain sufficient relief with the use of over-the-counter remedies like hydrocortisone cream and Calamine lotion; others require a visit to a physician to obtain stronger remedies. For mild to moderate cases, about one to two weeks is needed to get rid of the rash.