Q.Should first year lavender plants be pruned and if so when and how?
I live in upstate NY and planted lavender in June. It is now late September and I read conflicting answers re whether or not they should be pruned this first year. The lavender is about 8-10 inches high with just a few plants flowering.

In northern areas, prune lavender in spring. The extra foliage over winter helps a bit with winter hardiness. Longer stems also trap leaves which adds to the winterizing effect. Pruning to shape the plant is done in early spring. Do not cut back too far. If you remove all the leaves on a stem/branch, new leaves will not appear below the cut.