Many readers ask, "When is the best time to prune shrubs?" There are different reasons to remove wood from shrubs. If we're talking about old, dead wood or wood recently damaged by winterkill, then the question is quite different in nature from when we're discussing healthy wood.
Yes, trees and shrubs can often profit from a bit of spring cleaning, too. Dead limbs and winterkill on branches should be pruned off. This is the easy part of pruning: Remember, you can't go wrong pruning off something that's already dead. And life and death are "color coded" on trees and shrubs, just beneath their bark, with brown signaling death, green life. The key is determining where the brown ends and the green begins, which I discuss in my response to a reader asking about dead limbs on a magnolia.
But when is the best time to prune shrubs, in terms of healthy wood? Here, the question is different, because you can go wrong with your timing. And while dead branches should always be removed, the necessity of pruning off live branches is often determined by one's eye for beauty on a small shrub (to give it a more aesthetically pleasing shape).
The best time to prune shrubs in order to shape them varies from shrub to shrub, so let's begin with the broadest groupings of shrubs and work our way down to the shrubs that we should prune in early spring (if, in fact, our eye for beauty tells us they need pruning at all):
The question of the best time to prune flowering shrubs is the one that causes people more trepidation every spring, since improper pruning will result in the loss of the blossoming displays to which we so look forward all winter long. To simplify, think of it this way:
- Shrubs that bloom in spring have to have their buds already in place, on old wood (last year's growth), so that they're ready to kick into action when the warm weather comes; if you prune these branches off, you lose the flowers.
- But shrubs that bloom later in the year don't need that head start, blooming instead on new wood (growth produced in the current season).
Group 1 above includes flowering shrubs such as:
Wait to prune such shrubs until after they have finished blooming.
Group 2 above includes flowering shrubs such as:
You can go ahead and prune such shrubs in late winter or early spring, if you wish, without fear of losing blooms.
Plant Care in Spring: What About the Mulch Covering Perennials?
Regarding any deep layer of mulch you may have had covering your perennials during the winter, I suggest monitoring the situation to determine when to pull it away, so that the perennials can come through unhindered. I can't give all readers an exact date on when they should remove the mulch protecting their perennials: You have to play it by ear, and when exactly you remove such mulch will, obviously, vary according to where you live. But if you've applied a deep layer of mulch, it will eventually need to be scraped away from the ground immediately under which your perennials lie, as otherwise it may smother the perennials. The best approach, once the ground is starting to thaw, is to begin checking, in late winter or early spring, to see whether your perennials are pushing up. If they are, remove the mulch when it's warm out but replace it when the cold returns (until the cold stops returning altogether).
Plant Care in Spring: Dividing Perennials
Finally, some perennials can profit at times from being divided. Most perennials can be divided in spring, but there are some noteworthy exceptions. For examples, you'll want to consult my full article on dividing perennials.