Most will require blanching before freezing. It varies, so extact times are hard to say without knowing which you want to do.

Freshly picked is the only time to freeze them for best flavour. You need to refer to a book about freezing. Peas, or broad beans, for example, will freeze easily without blanching, and if you intend to use them up in a month or two then blanching is not necessary. French beans I find always benefit from blanching.
Blanching merely kills off enzymes and bacteria whose slow growth will cause unpleasant flavours over time.
In general though, people freeze vegetables and then leave them for far too long. It's recommended that you eat up all frozen vegetables within six months of freezing. We usually forget to do this, and end up with French beans still in the freezer when we are picking the new crop.