Hairy Bittercress

I have always called hairy bittercress the "fireworks weed” because of the way seeds seem to explode in every direction when the plant is touched. I was surprised to learn that this bitter herb is also edible. Let’s see what else we can find out about this persistent weed.

Hairy bittercress (Rasbak CC BY-SA 3.0)

Hairy bittercress description

Hairy bittercress (Cardamine hirsuta) grows as either an annual or biennial and it is a member of the cabbage family. As such, it has tiny white, 4-petaled flowers. Before the flowers emerge, however, you will see young hairy bittercress plants as small rosettes of oval leaves, growing very close to the ground. This basal rosette continues to grow in circumference until tall stems emerge. These stems may be 3 to 9” long and that’s where the flowers come in. Those upright stems branch in several directions, each with their own flowers and resulting seeds.

Immature hairy bittercress fruit (Public Domain)

How hairy bittercress grows
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Found pretty much everywhere, hairy bittercress prefers moist soil, open ground, and freshly disturbed areas. Like other weeds, it grows rapidly, often having two generations each year. You may think they have disappeared during the heat of summer but the first autumn rain will let you know that they were merely waiting for wetter conditions. These plants have long taproots.

Hairy bittercress seeds are held in capsules, called siliquae. When the fruit within ripens, there are valves on the siliquae that create a tightly wound coil. That’s why, when you touch them, seeds  explode in every direction. This method of seed dispersal is called ballochory.


Problems with hairy bittercress

Once hairy bittercress takes hold on your property, you will be dealing with it more and more each year, for better or worse. Because of its ability to fling seeds near and far, and grow quickly, hairy bittercress often finds its way into your garden on nursery plants. It is far simpler to put new plants into quarantine and monitor for weed growth right along with pests and diseases.

Before you shrug off this seemingly minor weed, you need to know that the real problem with hairy bittercress is the fact that it can host some nasty diseases. Specifically, tomato spotted wilt and cucumber vein yellowing can be carried into your garden on hairy bittercress. These diseases can have a huge impact on several of your crops, and not just tomatoes and cucumbers.

It is far easier to monitor the ground each spring and autumn for tiny rosettes and then use your long weeding tool to get under the taproot before it takes hold.