Reprinted from a post by Prairie Moon Nursery on the Native Plant Gardens in the Upper Midwest Facebook page:
“Around this time every year, we hear from many plant-lovers wanting that “pink-purple PHLOX that has suddenly appeared along their roadside or woodland edge”. Commonly mistaken for native phlox, these plants actually are Dame’s Rocket (Hesperis matronalis), a non-native, very invasive member of the Mustard family.
This illustration shows the major differences in Dame’s Rocket and Prairie Phlox (Phlox pilosa).
MUSTARDS like Dame’s Rocket have FOUR petals while native PHLOX have FIVE petals. Dame’s Rocket has ALTERNATE leaves and Phlox has OPPOSITE leaves.Imported from Eurasia in the 1600s, Dame’s Rocket, like most introduced invasive plants, lacks natural predators and diseases in North America. It thrives in most environments and is a prolific self-seeder and fast-grower. It can enter waterways, quickly overtaking native plant communities as it successfully competes for light and moisture.
Its recent spread has been accelerated by its inclusion in “wildflower” seed mixes sold commercially. Beware of nurseries that sell this so-called “wild phlox.” Whenever you can, please help to eradicate non-native invasive species and replace them with native species. We can each do our part to protect the integrity of our local environment! Here are the phlox species from Prairie Moon
NOTE: During 2018, Prairie Moon Nursery is including a free packet of Bergamot (Monarda fistulos) seed with each retail order. Details.
Thanks, Julia Lundmark Vanatta for bringing this post to my attention. Great illustration! Dame’s Rocket appears on 46 states’ noxious weed lists.
An easy way to remember which is which:
“PHLOX” has five letters / five petals
“DAME” has four letters / four petals.
Great word association, Janet — Donna
Is there a way to tell them apart before they flower?
You tell them apart from the leaves, Steph. The photo no longer exists. I will take a photo to replace that photo in a day of two. Keep checking — Donna
Steph — the dame’s rocket leaves are rosette leaves which is a circular arrangement of leaves that can grow up to 6 inches long. The leave are lance shaped about two to six inches long and wider at the base.
The phlox leaves are one to two inches long and are half a inch wide. The leaves are rounded at the base and pointed at the tip and slightly hairy on top with tiny hairs on the edges.