“We did not plant it, but a good size, exotic wild plant is growing in our yard. We would like to know the name of the plant and whether it is poisonous.”

Charles and Sheila Rhee, Mount Prospect

You have American pokeweed (Phytolacca americana) growing in your garden. It is a native herbaceous perennial that can grow up to 10 feet tall and is considered a weed in most situations.

It will self-seed and continue to spread in your garden if you do not control it. Most likely it got into your garden via a bird, as they eat the fruit. American pokeweed will be at home in many gardens, as it grows well in full sun to part-shade and in well-drained soils with average levels of moisture. I have found it growing strongly in sandy dry soils in Evanston.

The leaves are a bright green with reddish-purple stems and will blend in with other perennials when young. They start to stand out as they gain stature. The foliage will give off an unpleasant odor when crushed. The flowers are white starting in early summer and continuing into the early fall, so you should still be seeing flowers on the plants.

Dark blue-black berries that birds will eat will develop in late summer to fall. When you try to uproot the plant, you will discover that it has a thick, fleshy taproot. Some plants that I have tried to pull out have returned the next year, as I did not get enough of the roots out.

Be careful when working with this plant, as it is poisonous and can cause skin reactions when handled by some gardeners. Wear gloves to remove it and put any seeds that have formed in the garbage.

The plant will spread if you let it go to seed. Use a sharp spade to get more of the roots out if you can. You can also treat the cut end of the pokeweed with a nonselective herbicide like glyphosate to kill the plant. Monitor your garden next year and pull out any young plants that happen to come up — more likely than not, you’ll see it again.

For more plant advice, contact the Plant Information Service at the Chicago Botanic Garden at plantinfo@chicagobotanic.org. Tim Johnson is senior director of horticulture at the Chicago Botanic Garden.