When’s the best time to prune shrubs and hedges?

SALT LAKE CITY — Is it time to prune yet? It might be, depending on the shrub.

 

According to KSL Greenhouse Host Taun Beddes, there are three main questions you need to ask yourself to determine whether you can start pruning your shrubs and hedges: Does it flower? If so, when? And do I want those flowers?

For example, if you have a burning bush that you’re using as a barrier or a screen and you don’t want the flowers, you can go ahead and prune the hedge.

“But if you have lilacs, snowball bush, spring flowering spirea such as Bridal Wreath, those you need to wait,” Beddes said. “… If it’s spring flowering, wait. But, otherwise, you can prune.”

Using the renewal pruning method

Newer hedges—ones that are around three or four years old—only need a light haircut through a process called renewal pruning, which Beddes explained is when you remove 20% to 25% of the branches toward the base of the shrub.

Doing this will keep the hedge healthy because of the increase in leaf mass. Beddes said the leaves act as little solar panels that help produce energy for the plant.

“A lot of times we just do a straight wall, which is okay, … or we have a tendency to make them an upside down triangle, [but] that’s not what you want to do because the lower foliage is more likely to be shaded and it reduces the health of the plant. You actually want to prune in a rough pyramidal shape so that you can increase sun exposure to the lower portions of the hedge.”

Beddes said you can use the renewal pruning method on most bushes.

“It’s the best way to prune, whether they’re fruit-producing hedges or informal screens, or it’s just one that you’ve planted because you enjoy the flowers. Something like rose of Sharon that blooms from mid-July to almost frost, renewal pruning is the best thing to do for it. And so it’s just something that fits almost every situation.”

However, it’s not something he recommends doing in the fall. The rule of thumb is to never prune in a month that ends in “r,” so that would be September, October, November and December.

“Those are the four months that you don’t want to do major pruning, unless it’s like a hazard or a branch is dead or diseased,” Beddes said. “… Anytime from mid-March through late May into early June is the ideal time to prune, and early spring is the best, unless you have spring flowering bushes.”

Equipment maintenance tips

Effective pruning can only be done by using the right equipment the right way. That means your loppers and hand pruners need to be sharpened.

“Remember, though, that loppers and pruners are purposely only sharpened on one side. You don’t want to prune both sides because your branch, if you do that, is more likely to get caught up in the pruners and you’ll shred things. So just prune the one side and then make sure that … the hinges are oiled and then clean all the goo.”

When you’re done pruning, there will be a lot of sap left on the blades. To prevent rust, Beddes said you can use a Lysol or Clorox wipe to clean most of it off.

“You might have to use a Brillo pad or some steel wool to clean the rest off, but just maintain your pruners.”

Read more from the KSL Greenhouse show:

• All about roses: Types, bloom times, and care tips
• Dormant sprays: What they do and when to apply them
• UDAF offering grants to help create a more pollinator-friendly environment

KSL Greenhouse is live Saturdays from 8 a.m. to 11 a.m. Follow the show on Facebook, Instagram, and YouTube. You can also find more gardening info on our linktr.ee.