It is pruning time!

With all of the snow this winter, we have been a little busy to think about pruning. There is still time to get this project done. While some pruning is best done during the growing season for a few plant varieties, many are pruned during the dormant season when plants are still sleeping. The best time to prune for these plants is late winter, before leaves begin to emerge. If you think of it, when you have a snow mountain by your medium sized trees, you can (carefully) do a little climbing and reach your trees easily!


I often hear a lot of fear related to pruning. While timing and technique are important things to know, killing a plant by pruning is not too common. Here are a few basics:

Does your shrub bloom in the spring?

Lilac, forsythia, spring blooming bridalwreath type spirea, and magnolia are a few plants you can procrastinate pruning until right after blooming.  Will it die if I prune it in the winter? Unless you are especially aggressive with a pruner, not likely-but you might clip off the flower buds that are on the branch tips and stems preparing to open for spring. You can prune broken branches or correct minor issues, but avoid pruning all off the branch tips off so you can enjoy a spring display. If you aren't into flowers, prune away while they are sleeping in the winter. Otherwise prune right after blooming since they start making flower buds late summer and fall. 

Summer and fall blooming shrubs like potentilla, hydrangea, and most spirea can be pruned in the dormant season (November-March or before leafing). Once the snow melts and you can access the shrubs, you can get the pruning done before the leaves start emerging. Don't delay-spring comes quickly! Shrubs that are enjoyed for their foliage can be pruned at this time also. Burning bush, purple leaf sandcherry, ninebark, are a few examples. 

Most trees are best pruned during the dormant season with February-early March (or before buds start to swell) being ideal. During this time, insects and disease are less likely to spread and the wound will heal quickly with the active growing season to follow. It is also easy to see the form of the tree and you don't have to worry about damaging leaves. 

Some trees will bleed when pruned during this time-Maples (think maple syrup time in March!), birch, are examples. While this doesn't necessarily hurt the tree, if you prefer to avoid bleeding, wait until after the leaves have opened. 

One example of tree death caused by pruning )indirectly) is pruning oak trees that are prone to oak wilt at the wrong time. Opening wounds April-October makes easy entry for the beetles that spread the disease from tree to tree. The same goes for Ash when Emerald Ash Borer is around-lets hope the extra cold winter took a few of those buggers out! 

This should get you started, but check out the University Of Minnesota fact sheet on pruning for photos and further details. There are several techniques to keep in mind, so start with a plan and goal to your pruning.

University Of Minnesota "Pruning Trees and Shrubs" 

Don't miss the U of MN apple tree pruning video links in the article linked above. 

Happy pruning!

Kelsey Sparks

Green Barn Garden Center