15 Apr When and What to Prune
Let’s face it. Though we all love to have beautiful plants and landscapes, they do require some maintenance. One of the most common questions we get is about pruning. The answers to those questions vary with every unique circumstance, but there are some easy-to-follow guidelines to help you know what to do, when and how.
WHAT TO PRUNE?
All plants can benefit from pruning at some point in their stay on your property. In fact, regular pruning can extend a plant’s stay in your yard. However, it’s not necessary to prune ALL plants. We recommend planting shrubs, trees and flowers to minimize the amount you have to prune. This involves proper planning and spacing. That being said, some pruning will be required. So what plants will you need to prune? Prune plants you want to maintain size, promote denser growth habits, remove damaged leaves or expired blooms, and to guide shape. If you don’t have a need for either of those things, you can opt NOT to prune. Gold Mop Cypress, for example, look better when they are left alone and allowed to grow to their natural shape: a cascading pyramidal shape. Perennial plants will almost always need to be cut back when they go dormant (like Maiden grass and Rudbeckia). So, what you prune is your choice and can vary from year to year. One year you may want to prune some azaleas that are growing kind of leggy, but the next year they you may be happy with their shape.
WHEN TO PRUNE?
The larger question about pruning is WHEN? There are really 4 categories: Anytime, Before Spring flush, Fall, and After Bloom. Note that for most plants you can do minor pruning any time, but be aware that it could compromise some of the blooms. Also, one certain plant can fall into more than one category. Heavy pruning needs to be done in the fall as the plant goes into dormancy or just before spring flush.
The best practice is to prune plants after the first bloom, but for plants that are not prized for their bloom like boxwoods and small hollies, prune any time after first flush of new growth. This also includes Privet and Ligustrum.
Plants that ARE prized for their bloom should always be pruned after the blooms expire. This includes Azaleas, Hydrangeas, and Camellias. Note that some plants will bloom more than once, like Endless Summer Hydrangea and Encore Azalea. For these plants, prune once after first bloom to promote denseness of habit and then prune after subsequent blooms as desired for size and shape.
Many plants can benefit from a fall pruning. Deciduous shrubs (plants that lose their leaves) are best pruned in the fall. This includes Itea, Sweetshurb, Butterfly Bush, Beautyberry, Viburnum, Lilac, Kerria, Burning Bush, Knock Out Roses, and several others. These are typically pruned in fall because it minimizes the look of bare stems and twigs throughout the winter. Many of these can be pruned during the growing season if needed or before the spring emergence of new growth. Again, just wait until after blooms if during the growing season.
There are many plants that we recommend pruning just before Spring flush because of our, at times, mild winters. Also, in our zone, we experience warm spells after the first frost in which new growth starts to emerge. If you prune some plants in the fall, they are more likely to produce new growth at the pruning cut, which uses up valuable energy and nutrients the plants is saving for the true spring season. Therefore, the true spring flush will be less than desirable and there will be less energy for the plant to produce the blooms it usually does. Many of these plants are the same as the ones you can prune in the fall. However, whether you prune in the fall after first frost and whether you prune before spring flush is your discretion. We would probable recommend waiting until just before spring to prevent the former mentioned premature flush, but some people don’t like to wait until then because they don’t care for the dormant look of the plant. A good compromise is to prune these plants when you know there is no chance of a ‘warm up.’ For example, we do a lot of our pruning on these plants in December, January and early February. This is when we recommend hard, rejuvenation pruning. The plants are not actively growing and it’s less stressful.
Trees are plants too and can benefit from some selective pruning from time to time. Pruning trees is not usually necessary, but sometimes they can benefit. Each pruning cut causes the limb to ‘split’ and grow a denser habit. For example, occasionally a tree will shoot up one single leader out of the top. It makes sense to lightly prune this leader (or ‘tip’) to 1) make it divide into 2 or more limbs and 2) allow other limbs to catch up. This is prevalent on hollies. Hollies are fast growers and sometimes need some assistance to keep that nice pyramidal shape. We will also prune Maples, Japanese Maples and other trees to maintain shape and structure. You also may want to “limb up” a tree in order to make the trunk taller. This can really be done any time; just make sure you do it correctly so the tree is not damaged.