What is renewal pruning?

SALT LAKE CITY – During the past few weeks on the KSL Greenhouse show, many of the listeners have asked questions about pruning: How do I prune roses? When should I prune my forsythia? Should I even prune?

This led Hosts Taun and Maria to start a discussion on a process called renewal pruning.

Shrubs tend to grow very quickly, which is why people get the itch to prune them any time it gets too big. However, Taun warned against this as frequent pruning over 15 or 20 years can eventually kill many shrubs. Pruning too often will prevent them from collecting enough of the sun’s energy to keep it alive.

“If they don’t have the leaves to support the system because of our constant pruning, they die,” he said.

That is why Taun suggests using the renewal pruning method. This is the process of going inside the shrub and removing anywhere from 20% to 25% of the branches. Make sure to remove only the biggest and oldest branches.

“Over the period of 3 or 4 years, you will not have a branch in there that’s older than 4 or 5 years old. That will keep the size down,” he said.

When you use renewal pruning, you’re leaving stubs inside the bush. On these stubs are buds, which generate more branches that will leaf out.

“Because you have leaves on the entire length of the branch… they’ve got a lot more leaf surface to support the system, and they stay healthy,” Taun said.

The KSL Greenhouse is on every Saturday from 8 a.m.-11 a.m. You can follow the show on Facebook, Instagram, YouTube, and on our website.