Michigan just banned the sale of six invasive plants, and it’s a big win worth celebrating.

The not-so-great news? We already have millions of acres across the state covered in the stuff. The ban should help keep things from getting worse, but it doesn’t clean up what’s already here. 

So let’s get to work, shall we? Here’s your July list: four stubborn invasives taking over Michigan, how to spot them before they spread and how to take them down.

Black swallow-wort: A Common milkweed lookalike, this vine may have already finished blooming by the end of June and is likely in the seed-producing phase. Look for seed pods on the plant.

  • Where to look: Woodland edges and fields. 
  • Identification tip: Unlike Common milkweed:
    • Seed pods are thin and narrow, and they’re not fuzzy
    • It’s vining; milkweed stands upright on its own
    • The flowers are small, dark purple and star-shaped 
  • What to do: You have a few options with this one right now; if it’s just a few plants, you can dig them up, but be sure to get every part of the root system (they’re usually deep and plentiful. If the plants have already formed seed pods, note their location and collect the pods. Then burn them to prevent the spread and add this plant to your to-do list for June of next year. If they’re still flowering, you’re in luck and can apply an herbicide – Trilopyr tends to be the best option. 

This swallow-wort on the left has seed pods and a few remaining purple flowers. The plants on the right still have the dark purple star-shaped flowers. Both feature the narrow, glossy green leaves.

Bush honeysuckle and Autumn olive: These two have already flowered and are fully into berry production by early July.

  • Where to look: Unfortunately, everywhere. This one grows in full sun and shade, and everything in between. 
  • Identification tip: Cut the stem and see if it’s hollow. If so, it’s the invasive version of honeysuckle. 
  • What to do: Late fall is the ideal time to treat this one, but you can start now and monitor for regrowth. I usually follow the cut stump method. I cut the shrub down to its base (with about 3-4 inches remaining above ground) and paint the stump with triclopyr. I use a Buckthorn Blaster and add blue dye, so I know which ones I’ve already done.

Ripe berries on Bush Honeysuckle are eaten and dispersed by birds, furthering their spread.

Multiflora rose: Mid-summer is the time to see these bushes in bloom, with white (and sometimes pale pink) flowers. It can reach up to 10 ft. tall, so it’s taller, bigger and more extensive than its native counterparts. 

  • Where to look: The shrub does well in most environments – sunny, light shade and even under the forest canopy.
  • Identification tip: Where the base of the leaves connects to the branch, you’ll find tiny, fringed hairs that native roses don’t have. Here’s a closeup of what they look like.
  • What to do: The cut stump method I use for honeysuckle also works here. You can foliar spray, but I stay away from it since it’s hard to avoid overspray and uses much more chemical. 

As with all invasive plants, learning how to identify the plants when they’re much smaller than this shrub makes removal and eradication much, much easier.

Invasive round leaf bittersweet:

  • Where to look: Does it sound like I’m just repeating myself by saying “everywhere”? But that’s what makes these plants SO hardy – they find a way to thrive in a wide variety of locations. 
  • Identification tip: Identifying this one varies depending on its age. If it’s an established vine growing up a tree, it’s going to look embedded in the tree, like it’s trying to strangle it (which it actually is). There may already be yellow berries on the vine. Young vines will have glossy green and round leaves that alternate along the stem. There is a native bittersweet, and this guide helps tell the difference between the two. 
  • What to do: Yep, you guessed it- it’s cut stump time. The same principle above applies, too. You can foliar spray, but a dab of triclopy on the vine does the trick. And for the big vines, you’ll definitely want to cut the stumps and paint them.

These are the Invasive round leaf bittersweet berries in the fall, but you can see the yellow shell to look for in the summer.  The photo on the right shows the vines starting their climb up and around the tree. 

Let’s get to work: Have you spotted any of these four troublemakers in your area? Drop a comment below with your battle stories or your go-to eradication tips.