Just last summer (2015) I planted a 16′ purple robe locust in my west-facing front yard in Toronto. We fertilized and watered this plant aggressively and it has now grown to about 30′ and is really taking hold.
Is it too early to prune/shape the tree? Over the first winter, we lost quite a few large branches, but the tree has grown back quickly…. however, the shape is quite uneven and the tree is looking a little too wild.
Should we wait until the tree is a little older? or would it be okay to prune this tree before winter this year?
You seem to be taking good care of your tree. The branches of Purple Robe Locust (Robinia pseudoacacia ‘Purple Robe’) are brittle and tend to break in high winds. Accordingly, you should continue structural pruning when the tree is young to ensure that the tree has strong structure which may reduce the likelihood of branches breaking off.
Deciduous trees can be pruned at any time to remove dead or diseased branches. However, as the Purple Robe Locust will bleed if pruned when the sap is running in the spring, you should prune either in the winter when the tree is dormant and you can clearly see the shape of the tree, or in late spring/summer after the leaves are fully out.
You might consider consulting with a tree care professional to ensure that you are pruning your tree properly to promote the appropriate growth pattern. A listing of arborists and tree care specialists is available at Landscape Ontario: www.landscapeontario.com.