Ask Mr. Smarty Plants

When we searched our Native Plant Database for the genus Castilleja (paintbrush), we found 49 species of that plant, of which two, Castilleja coccinea (Scarlet paintbrush) and Castilleja septentrionalis (Labrador indian paintbrush) were native to Michigan. The Scarlet paintbrush is native to Grand Traverse County, as seen in this USDA Plant Profile Map.   Castilleja septentrionalis (Labrador indian paintbrush)   is not, USDA Map. These are not necessary facts to address your problem, we just like to know what plants we are talking about.

You can follow each plant link to read our webpage on that particular species. You will learn that it can be an annual or a biennial, meaning it blooms the second year after it is planted. From our webpage on Castilleja coccinea (Scarlet paintbrush) (which read by following plant link above):

"Conditions Comments: Roots grow until they touch the roots of other plants, frequently grasses, then penetrate the roots of these host plants, obtaining a portion of their nutrients. Transplanting paintbrush usually kills it."

The genus Castilleja (paintbrush) is considered hemiparasitic, which means it attaches itself to other plant roots to get nitrogen. In Texas, paintbrushes frequently appear with Lupinus texensis (Texas bluebonnet), which is a nitrogen-fixing plant in the soil. We are just guessing that the ones in your yard are getting their nitrogen from your grass.

They are a beautiful native flower and we hate to encourage their destruction, but we understand you want grass, not grass and flowers. As you saw in the quotation above, they do not tolerate being transplanted, so we can't even suggest you find them another home. Being annual or biennial, and not capable of being transplanted, just keeping them from seeding will prevent their return. Of course, if there are other stands of the plant in the neighborhood, they will be replanted. This paintbrush blooms May, June and July, probably later in that timeframe as far north as you are. Simple mowing should suffice. You mow the grass anyway, we assume, so set the height down a little, and each time you mow you will destroy more of the seed-making apparatus. Or, you can start earlier in the year and pull the plants out before they even have a chance to start making seeds.

The paintbrush is a dicot, or broad-leaved plant; your grass is monocot, or narrow-leaved plant. There are specific herbicides for monocots or dicots, so you could theoretically spray a dicot herbicide to kill the paintbrush and not hurt your grass. However, sprays can easily light on other broad-leaved plants, like trees, shrubs and ornamental flowers you want to keep, having bad consequences. We suggest you stick with manual removal before the paintbrush goes to seed.