Roadside invasives – Sticks & Stones

Roadside invasives

Dames Rocket

These days I have a forty-minute commute to work, and I enjoy the progression of bloom through the season, of everything from landscape ornamentals to woodlots and farm fields. There is always something happening. There are some plants I would like to see less of, though.

In late May the purple, white and pink flowers of Hesperis matronalis, aka Dame's Rocket, bloom in abundance all up and down the roadsides and into fields and woodland edges. I love it, and I don't - it's invasive, having long ago escaped into the wild. It sows itself with abandon, soon forming vast colonies that crowd out and replace native plants. Related to Garlic Mustard, it spreads just as aggressively. If you like the look I would steer you to the tall phloxes, like P. paniculata or P. divaricata because we do not need any more of this plant. Don't get me started on Garlic Mustard, it's not even pretty.

Dames Rocket

But who says invasive plants *have* to be ugly? Here's another one that is a common sight in Michigan, Hemerocallis fulva, aka Ditch Lily. It's not a true lily, but a daylily, and not a neat clump-forming one, either. No, it spreads by rhizomes and forms large colonies filling the ditches on either side of roads all over the state. I like seeing the cheery orange flowers every summer but again, it's busily crowding out native plants. 'Kwanso' is a double form that is offered in the trade, it is not nearly as aggressive. 

Hemerocallis fulva

One of the worst offenders is the notorious Lythrum salicaria, aka Purple Loosestrife. In spite of decades of trying to knock it back, by physical removal and the introduction of several species of beetle that eat it, it still occupies acres and acres of wetlands across the entire continent. None of our native animals or insects really need it for either food or shelter and I am personally over the obnoxious color of the flowers, too, because they just remind me of the futility of trying to put the Genie back into the bottle.

Purple loosestrife

There was talk at one time that some of the named varieties were sterile or nearly so, but it turns out that they breed just fine with the wild ones. So even if you find it for sale, don't plant it. If you have it on your property, get rid of it. 

Purple loosestrife

There are loads of invasive plants loose in Michigan, from Autumn Olive to Phragmites, Buckthorn to Spotted Knapweed, Multiflora Rose and Oriental bittersweet, to the honeysuckles - oh, boy, the honeysuckles... To all of them I say, hit the road! 

invasive honeysuckle

For more information about these and other invasives, check out these links!

Holly Christensen