What blessing is said before tomatoes? And after?

Tomatoes grow from the ground (not on trees), so they receive 'Borei pri ha'adama' ('Creator of the fruit of the ground'). The after-blessing is 'Borei Nefashot.' The distinction between 'pri ha'etz' (tree fruit) and 'pri ha'adama' (ground fruit) depends on the plant's nature: if the plant has a permanent trunk/stem that survives winter and produces fruit again the following year, it's considered a tree and its fruit gets 'pri ha'etz.' If the plant dies or must be replanted each year, its produce gets 'pri ha'adama.'