Hi, this is a picture of my dapple willow that I grew from a cutting. It is in its second year and is looking straggly. Should I trim it a little now or wait till spring? I live in Bolton, Ontario, zone 5. Feedback would be appreciated.
Kind regards.
Thanks for reaching out to Toronto Master Gardeners. There is also a Lake Simcoe South Master Gardeners Group but we are happy to answer your question.
How wonderful that you have a dappled willow that you grew from a cutting that is clearly doing well!
The short answer to your question is no, it would be safest not to prune or shear your dappled willow just now.
Pruning stimulates growth and according to this guide from Purdue University : “pruning in late summer should be avoided since it stimulates succulent growth which may not harden sufficiently to avoid winter dieback.” This time of year is right on the border of when pruning might cause winter dieback for shrubs. If the coming winter is late and mild you will have no problems but if the winter comes early or is harsh it’s possible that the new growth that results from pruning now will be killed. Your plant will survive but the dead tips will be ugly, and all that growth will be wasted.
Pruning should be done while dormant, in either early winter or VERY early spring before catkins appear and any growth begins.
This guide on Pruning Shrubs and Hedges from the University of Maryland Extension shows approaches to pruning and shaping shrubs. From your photograph, pruning could limit the size of the plant, establish its shape and structure, and encourage the growth of the new, variegated shoots that the dappled willow, Salix integra ‘Hakuro-nishiki’ is grown for. You could take the approach of thinning to choose a few main branches and allow the plant to continue to grow in its current more open form. However, it is more common to prune willows to create a more dense, hedge-like plant. You can do this by pruning according to the diagram for year two shown under “informal hedge.” Every year in late winter you can continue to prune using the techniques in these two guides.
Once your plant has reached the size and shape that you wish, shearing off new growth regularly from late spring until mid-August will stimulate fresh growth of the colorful foliage and shearing will maintain the desired form. This guide recommends shearing back new growth before it gets to a foot long. Your plant seems to be growing in part shade so it may grow less vigorously and require shearing only once for the season. However often you decide to shear the plant, remember to do the last shearing before the end of August.
When your plant is more mature and is growing so vigorously that its size is getting out of bounds, despite regular shearing and pruning, you may use another technique called coppicing or stooling. This involves cutting the whole plant down, as close to the ground as possible, in late winter. This will result in regrowth of many new shoots and a rejuvenated plant. You can see a picture of a dappled willow pruned in this way under “Total Rejuvenation Pruning” here: Tidying up your plants – MSU Extension. A combination of coppicing, pruning, and shearing can allow you to keep your plant growing at the shape and size that you want for many years.
We hope that this information will help you decide how to maintain your willow shrubs.