Happy (almost) March, everyone! Spring is almost here! We’ve been busy moving snow and ordering plants, and have now entered into the main pruning season. Pruning helps rejuvenate new growth, provide structure and shape for health and aesthetics, and keep paths and walkways clear for workers and guests. Here at Wellfield, we have a diverse collection of trees, shrubs, and semi-woody herbaceous materials requiring care and maintenance at a variety of dates throughout the seasons.
In general, most pruning can be done while the trees/shrubs are dormant, typically throughout the winter months. There are exceptions to this rule, however. Many spring-flowering shrubs should be pruned after the flowers have faded, around early summer. Heavy sap-producers such as birch and walnut should be pruned late summer through mid-winter when the sap isn’t flowing as hard to minimize “bleeding.” Consequently, it is not advised to prune many of the heavy sap-producers very hard at any time. Coniferous plants should also be spared from heavy pruning, with the exception of some yews and young Chamycypaeris.
Summer pruning usually involves re-training our fruit espaliers to correct any growth outside of the desired pattern. Maintenance pruning on dead/diseased/damaged branches and the removal of suckers can be done throughout the year. It is a little overwhelming to keep all the dates in mind, but with a little memorization of the basics, looking up information on specific species or varieties can get you the rest of the way to happy trees. Many plants (especially non-sappy ones) are forgiving if the timing is a little off. Maintenance pruning is also more tolerable outside of the timelines, as opposed to “hard” or “regenerative” pruning, which should stay within the recommended windows. And, as we know, suckers can and should be removed whenever spotted!
When pruning for general maintenance, first look for any diseased, dead, or damaged branches to cut first. Then check for any branches that are rubbing (look for criss-crossing branches or branches that are very close together) and remove any offenders. After these cuts are made, remove any growth that is over-crowded and blocking air flow or sunlight. Make sure to understand the overall design appeal of the tree/shrub, though. A hedge should be a lot denser than a maple tree! We like to leave some trees/shrubs a little bit more dense to cover maintenance areas or create a more enclosed space and reduce lines of sight in some areas of the garden, such as the English Cottage Garden, Waterfall Garden hedge, and along the fence near the large water tanks in the Water Celebration Garden. Trees and shrubs near the water’s edge are pruned to give an open view across the ponds. And of course, the Island Garden is full of unique Japanese-style pruning that Cody and I continue to receive training on to correctly accentuate the intent of the garden. It’s also advised to make sure your pruners are sharp and appropriately sized for the job to reduce any damage or tearing to the plant (and pruners!). We like to use a little rubbing alcohol to sterilize blades in between species/locations. Don’t be afraid to employ a small, curved pruning saw when loppers will not suffice.
Occasionally, hard pruning must be done to rejuvenate a lackluster tree/shrub, to repair damage after a severe storm, or to train a younger plant to grow into a very specific shape. Fortunately, most of Wellfield’s trees and shrubs are healthy and have been adequately pruned to their desired shapes throughout the years, and we’re mostly just maintenance pruning at this point. (The Island Garden is the exception, as it is relatively young and still undergoing appropriate shaping). I experienced training a young plum into a fanned espalier shape a few weeks ago. I’m hopeful it will grow to fit nicely with the others! We have a variety of shrubs that are hard pruned every year for maintenance at the beginning of the growing season. These include: Japanese kerria, spiraea, beauty berry, small willow shrubs, buddleia, and most non-woody hydrangeas. It’s also acceptable to cut back dogwood, ninebark, and elderberry shrubs, if desired to correct form or thin out.
There are several types of complicated pruning styles, along with tips for repairing and rejuvenating damaged specimens, which can best be accessed through proper manuals. We use the American Horticultural Society’s Pruning & Training as our guide, and there are plenty of great books out there. These reference guides are full of some really cool techniques that can seem a bit challenging at first glance, but with patience and careful reading, you’ll feel ready to create your own Belgian Wall, Pollarded Smokebush, Pleached Hedge, and Spiral Topiary!
Mary Wojcik, Horticulturist
One thought on “Winter Pruning and General Tree/Shrub Maintenance”
I am hesitant to write about winter pruning. There is so much to say. Sadly, now that all the orchards are gone from the Santa Clara Valley, there are almost no arborists or horticultural professionals who prune deciduous fruit trees properly.