For most shrubs and trees, pruning is a necessary task that not only tidies their appearance but also encourages new growth and maintains their overall health. But many gardeners are fearful of pulling out their shears and cutting their beloved plants – and for good reason. Depending on the plant and the time of year, pruning can sometimes do more harm than good. With our Illinois pruning calendar, you can be confident in your pruning choices this spring, and every other season!
Pruning in Late Winter
Although we’re still very much immersed in the below-freezing temperatures of an Illinois winter, preparations for the growing season are definitely underway! Before you begin, proper pruning should always start with clean, disinfected, and recently sharpened garden shears. As some varieties of shrubs and trees are actually out there waiting for their trim right now, we’ll start off our pruning calendar with the winter season.
While many fruit trees don’t require annual pruning (if they’re properly trained), they can benefit from some trimming in their younger years. The best time to prune them is while the tree is still dormant, in late winter or early spring. Remove any dead wood or stray, weak branches that hinder fruiting. Be careful that you don’t prune any fruit trees that bloom on last year’s wood, like apples or cherries.
Summer-blooming shrubs, like Hydrangea, Rose of Sharon, and Potentilla, set their buds on new wood in the spring. Encourage new growth and branching by pruning these shrubs now in late winter. With all the new growth, you’ll enjoy plenty of blooms when summer finally arrives.
For property owners who like to revitalize your homes in the name of spring cleaning, you’re likely already thinking of ways to extend this urge outside your homes and into your garden. While spring is a great time to tidy the yard and prune your plants, there are some things to remember.
Spring-blooming shrubs, like Lilacs, Viburnum, Azaleas, Forsythia, and Rhododendrons, flower on last year’s wood. This means their blooming buds are set well in advance, during the summer of the previous year. If you prune them too early, you’ll likely end up removing good buds and losing out on many of this year’s flowers. The best time to prune these shrubs is later in the spring, only after their flowers have faded and before they start setting their buds for the next year.
While sap-producing trees, like maple and birch, can be pruned in the winter, they’ll end up “bleeding” a lot of sap at that time. While it’s harmless to the tree, many people opt for a late spring or early summer pruning to avoid the mess. Wait until the leaves are fully opened, and be careful not to remove more than a quarter of them.
Later in the spring and early in summer, it’s time to return to your fruit trees. One of the biggest problems with any fruit tree is when they over-produce, leading to an abundance of small, poor fruits. By plucking some fruits, you’ll divert more sunlight, energy, and nutrients to the remaining ones, improving their quality.
Many will argue that summer isn’t a great time to prune your precious trees and shrubs. The idea is that it’s much safer to prune while plants are dormant to prevent the risk of contracting diseases from the open wounds. While these concerns are valid, there are some exceptions to the rule.
Plants from the prunus family, such as plums, peaches, nectarines, apricots, and almonds, should only be pruned during the summer. The biggest threat to these trees is silver leaf, a fungal disease that spreads through spores in the air from late fall to spring. Summer pruning of these trees massively decreases the risk of being infected by one of these spores!
While major pruning should be kept for other seasons, routine trimming is usually fairly safe to do in the summer. Dead or diseased wood will pose more of a threat to your landscape than a few small cuts. Near the end of summer, cut the stems of spent flowers to encourage re-blooming.
After the leaves have fallen and all that’s left is the skeleton of your tree, it may seem like the perfect time to prune away the problem branches. However, this can actually be very damaging to your tree. Although it’s tempting to pick up your shears, you’re better off focusing on other chores instead.
Pruning deciduous trees stimulates new growth, especially if followed by a few warmer days. This causes the tree to use valuable resources on growth, at a time when it should be preparing for dormancy. Trees need these energy and nutrient stores to be self-sufficient throughout the winter when their roots aren’t able to supply any more.
Like everything else when it comes to gardening, there’s always an exception to the rule. It’s actually recommended that Elm trees be pruned in the fall, as they’re susceptible to the Dutch Elm disease. The Elm Bark beetle, which carries the disease, is most active during the spring and summer months, where it infects trees through open wounds. For Elm trees, it’s recommended to prune in the fall or winter to avoid this disastrous pest.
No one wants to see stray, feeble, or dead branches detracting from their marvelous flowers and foliage, or worse yet, getting caught in power lines. But no one wants to encourage those things through the introduction of pests and disease, either. Encourage healthy plants, bountiful blooms, and a beautiful garden aesthetic by pruning the right way, at the right time.