Bane of my existence. At least one of them when it comes to gardening. This one is called Hairy Bittercress or Shotweed. Formally, Cardamine hirsuta.
I have a love hate relationship with them. Why love? Well, I was a biology major and I am really impressed by their evolutionary adaptation. They start growing in the spring. They have a little tuft or rosette of leaves near the ground and then a stalk shoots up and they have little white flowers.
So far, so good. The problem is when the flowers go to seed. They have little seed pods with a number of seeds in each one. Even that is not too bad. But, when they have matured enough, some sort of trigger mechanism is created. When you touch them or try to pull them, the seed pods shoot with some force and can go as far as 10 feet without wind. It is helpful to wear glasses, be careful of them shooting in your eye.
Very impressive way to survive and propogate. If a person or animal tries to eat them or pull them as weeds, the seed pods get away as little survival capsules before destruction of the plant.
Why do I hate them? Because they are worse than rabbits, they spread like crazy.
How to combat them
They are actually fairly easy to pull since the roots don’t seem to go very deep. Also, since they grow in spring, the soil tends to be moist which also makes it easier. If the soil isn’t wet, you should wet it before weeding.
But, the key is to not procrastinate. If you get them as they are flowering or as the seed pods first set, they don’t shoot off. So spend a few minutes each day going around pulling them and stay ahead of them. You may not get them all the first year, but you should not have many the second year if you are diligent.
Don’t let up, or they will come roaring back. I suppose you could hit them with weed killer but they are frequently among things you don’t want killed and I don’t know if the week killer will destroy the seeds in the pods or not.