Hairy Bittercress
Cardamine hirsuta

This is a very common wildflower of towns and gardens and is found on wasteland, cultivated and rocky ground, old walls and pavement cracks. Its flowers are so small it can easily be overlooked. They nestle in tight clusters at the tips of the stems that gradually lengthen as the plant grows. It has a few other names, pepperweed and shotweed that relate to the way the seeds are propelled from the seed pods.