Cardamine hirsuta is very prolific.
A seedling in less than 2 weeks can flower,
have seedpods and spray seeds in every direction.
And it does not resemble chickweed at all.
Even as a seedling, it starts out with heart shaped leaves,
![](http://www.theseedsite.co.uk/bittercress2.gif)
not pointed ovate leaves like chickweed. (Stellaria media)
![](http://www.theseedsite.co.uk/chickweed2.gif)
Cardamine hirsuta has ferny, almost lacy, frond-like divided leaves.
![](http://oregonstate.edu/dept/nursery-weeds/weedspeciespage/bittercress/foliage_750.jpg)
Not single opposing pointed ovate leaves like chickweed.
![](http://www.cas.vanderbilt.edu/bioimages/s/wstme2-wp17935.JPG)
No way to confuse the two...except that they both have green leaves and white flowers.
Cool website to ID weeds.
http://www.theseedsite.co.uk/weeds2.html