Some other bad actors
Garlic mustard is growing explosively in New London right now. It has small white flowers and corrugated, heart-shaped leaves. It spreads by seed on its own, and doesn’t need help from birds. Pull it before it sets seeds. You’ll know it by its rank, onion/garlic smell when you bruise the stems or leaves. Pull every leaf you see, or your yard will be overrun in short order.
We can’t blame the birds for Norway maple seedlings—the winged seeds helicopter in on the wind. If you live in New London, there is probably a Norway maple within a few feet of your house. Thousands of seedlings seem to sprout every spring. Pull those while they’re babies, before you need loppers or a chain saw.
Privet, also spread by seed, is another pest emerging now. Yank it out when it’s tiny. Privet was widely used as a hedge because it’s easy to shear and grows prolifically.
Two armed invaders
Barberry is a common garden plant, one of the few shrubs totally impervious to deer. It is well armed with painfully sharp spines, so it can be difficult to remove when it gets large. Birds spread it by seed. Another armed invader is the multiflora rose, which can form massive thickets. It has charming small white flowers and loads of hips, the seeds much enjoyed by birds. Some species of barberry are still available for sale in Connecticut, but have been banned elsewhere. You’ll never find anyone selling multiflora, but it came to the U.S. for use as rooting stock for garden roses and managed to escape.
Honeysuckle is another example of an invasive that is very early to leaf out—in fact, it’s just starting to show flower buds in New London this week. Birds enjoy its succulent red fruits in summer, spreading plants far and wide. There are several species of shrubby honeysuckles that are problematic. They have fragrant flowers and a single shrub doesn’t seem that troublesome, but one becomes hundreds within a few years. And that’s a potentially big problem.