Good Gardening: Pruning

Jul 6, 2020

On any pruning cut, try to leave the branch collar- that slight swelling where the branch joins to the main trunk.
Credit John Fischer / KLCC

You won't hear me talk about ornamental plants much. I put my energy into things I can eat. But there are places near the house where edibles won't do well, so something pretty is better than nothing.

If you don't prune shrubs and bushes near the house, eventually you can't see out the window or get near the structure for maintenance. But to keep the form of the plant while controlling its height and spread requires pruning out full branches, not just cutting back the tops of existing growth.

John Fischer's lilac bush got a little bigger than he'd like while he was busy tending vegetables.
Credit John Fischer / KLCC

Just shortening existing growth will turn every plant into a hedge, and if you only cut the tops off branches, you may remove setting flower buds that will bloom next spring. We'll use my lilac as an example- it's grown too large while I've been out tending vegetables.

In an ideal world, don't take more than one third of the plant off in one year. It’s not quite too late to prune spring bloomers, but some shrubs prefer a dormant pruning time. Check online to see your shrubs preference.

Select a few finger sized shoots that you want to become the new main structure of the plant, and cut off the overly tall branches as low as you can. With some plants that will be down to the ground. Choose replacement shoots that will thrive with the extra light and space provided by removing the older growth.

John Fischer gave this lilac a healthy pruning, taking off a bit more than a third.
Credit John Fischer / KLCC

If the branches are large enough, cut them off in a few pieces so that the weight of the branch you are cutting does not peel bark off past your final removal cut. On any pruning cut, try to leave the branch collar- that slight swelling where the branch joins to the main trunk.  And don't paint anything onto the cut. Sealing the wound will likely cause more harm than good.

I have included a few before, during, and after pictures, and yes I did cut off a bit more than a third. I'm dealing with something old and hardy, and the plant has been there for a long time too. It's weathered a few "Ooops, how did it get so big" pruning jobs before.

I'm John Fischer with KLCC's Good Gardening.