The Plants We Brought With Us

I’ve been thinking about invasive plants lately, particularly how many of them ended up here in the first place. Most weren’t introduced with any intention of causing harm. Someone thought they would make a good landscape plant, provide wildlife habitat, prevent erosion, or solve some other problem. In many cases, those plants did exactly what people wanted them to do. They just kept going.

Even the grass in our lawns is an interesting example. Kentucky bluegrass, perennial ryegrass, and several other common lawn grasses aren’t native to most of the United States. We’ve become so accustomed to them that we don’t really think about their origins. Of course, being nonnative doesn’t automatically make something invasive. Plenty of plants from other parts of the world grow perfectly well in our gardens without becoming ecological problems.

The distinction gets complicated because a plant that’s considered invasive in one region may not be classified that way somewhere else. We grow some ornamental plants, including creeping Jenny and selections of ground ivy, that are considered invasive or undesirable in certain areas, including Indiana. They’re useful in containers, but that doesn’t mean they can’t become problematic if they escape cultivation. Both are prohibited in certain landscaping situations in Bloomington, Indiana, even though neither appears on Indiana’s statewide list of 44 prohibited invasive terrestrial plants.

As growers, I think we have a responsibility to understand those differences rather than assume every plant is appropriate everywhere.

There’s another dimension to this discussion that doesn’t get much attention: allergies. Changes in vegetation, pollen production, and growing seasons can affect people as well as ecosystems.

This week we’re looking at new research on invasive plants adapting to cities, some familiar plants that have become a problem in Indiana, and why our allergy seasons may be changing.

And with our poinsettias starting to color up, a look at some that barely look like poinsettias at all.