June’s Weeds of the Month: Houndstongue & Black Henbane

Spring has almost passed and summer is just around the corner. The buttercups, spring beautys, and chokecherries have already lost their blooms, and Arrowleaf Balsamroot is lighting up the hillsides. A few noxious weeds are also going to flower during this transition. Since flowers lead to fruits and seeds, and seeds lead to many more plants, these flowers are warning us – if you don’t stop me now, my progeny will haunt you for years to come!

June’s Weeds of the Month

There are two particularly unpleasant weeds flowering at this time that you should prevent from making a deposit in their “seed bank.”

Houndstongue is a plant in the borage family. Its deep magenta flowers are small, 5-petaled, and grow along wiry stalks. When pollinated, these flowers produce a fruit composed of 4 prickly burs that seem to leap from their stalk and readily stick to any passerby, just like velcro. The hitchhiking burs each hold a few seeds that will inadvertently be planted wherever their host discovers them, picks them off and drops them on the ground. Please, if you find these hitchhikers on yourself or your dog, pick the seeds off and dispose of them in a way that prevents future germination.

Photo By: Richard Old
Houndstongue fruits produce 4 velcro-like burs containing seeds.
By Photo: Ben Legler
Houndstongue produces 5-petaled magenta flowers along wiry stalks.

Houndstongue is a biennial plant. It produces flowers, fruits, and seeds in its second year of life, and usually dies after reproducing. If you find it in its first year of life, it will look like a cluster of long, hairy, tongue-shaped leaves with pointy tips. It can be confused with native arrowleaf balsamroot mentioned above, as that plant also produces a simple cluster of leaves its first year and those leaves are a similar shade of green. But look closely at the bases of the leaves and you will notice that balsamroot has a distinctive spade-shaped base while houndstongue leaves simply taper to a point at their base.

Balssamroot leaf



Houndstongue leaf
Balssamroot leaf bases resemble a spade. Houndstongue leaf bases taper to a point.

Whether the Houndstongue is in its first or second year, it can be killed by pulling it out by hand if the soil permits. If chopped out below the root crown, it rarely grows back. If the infestation is too large to hand-pull, purchase herbicide at TCWP and use a surfactant to be sure the herbicide permeates the hairy leaves. Seal any seeds in a plastic bag and put them in the trash.

Photo by: Richard Old Black Henbane

Both Houndstongue and Black Henbane can be controlled by hand pulling or by chopping out below the root crown. An herbicide used with surfactant can be used to control larger infestations.

Another nasty noxious weed that is blooming now is Black Henbane. This member of the nightshade family plant is unmistakable. Its leaves look like a head of cabbage and its unattractive, foul-smelling flowers look like they might appeal to dung beetles or houseflies as pollinators. Once pollinated, its flowers produce pineapple-shaped fruits packed with small black seeds.

Photo By: Richard Old
Black Henbane flowers are unmistakable.
Photo By: Richard Old
Black Henbane resembles a head of cabbage during its first year of life
Photo By: Richard Old
Black Henbane produces up to 500,000 seeds per plant.

Both of these plants have the same biennial growth habit and can be controlled in the same way. Both are also considered poisonous to animals and people when ingested, so be sure to wear gloves if you are hand-pulling.

If you encounter these plants around Jackson, you can send us a “weed report” by using the “service request” function on our website www.tcweeed.org. Remember to PlayCleanGo so you don’t spread their seeds into uninfested areas.

Photo credits: Ben Legler, Richard Old, XIDservices, Utah State University, Bingham County Weed Dept, Montana State University Extension