Cow parsley is a hollow-stemmed, tall plant that grows rapidly in the summer before dying back. It likes shady habitats in particular, and can be found decorating woodland edges, roadside verges and hedgerows with masses of frothy, white flowers.
Sow in the autumn directly where they are to flower. Sow 1mm deep, thinly, in drills 30cm apart in prepared soil that has been raked to a fine tilth.  Cover lightly.