When I was little, my mom would sometimes make me eat things I didn’t like, like lima beans. If you were a baby deer, called a fawn, you wouldn’t have that problem.

Deer get to pick out what they want to eat, and it turns out that they don’t like plants that aren’t native. Plants like garlic mustard and Japanese stiltgrass are the lima beans of the deer world. No deer wants to eat them.

Nonnative plants are ones that have had their seeds carried here from somewhere else. It’s believed that Japanese stiltgrass came to the United States around 1919 when it was used as packing material in shipments of porcelain.

Spotted knapweed, which has a beautiful purple flower, is a nonnative plant and is also a weed that has spread widely since nothing eats it. Researchers have worked hard to try and keep knapweed from spreading.

Scientists did a study to see if deer eat nonnative plants. They found that the deer would rather eat native plants. The problem is: If there are a lot of deer eating only native plants, the nonnative plants grow and spread. That means more nonnatives and fewer natives over time. Deer could be eating themselves out of house and home while also changing what grows in the forest. That could be bad for a lot of other animals and insects, as well.

Researchers think the answer may be to reduce the number of deer where there are too many, or by fencing out deer in some places. That way some of the native plants may have a better chance of growing big and healthy and spreading their seeds.

— Brett French, french@billingsgazette.com