Hello – Thank you for reading my question. I’d like to help my willow shrubs keep their vase-like shape after removing (almost all) the dead wood in Feb/March. They are 15-20 years old. Should I just cut 1-2 ft off the top in late winter, removing the tiny ground shoots? (I’ve seen Martha Stewart go so far as to cut back all side shoots to the main branches, and others coppice to the ground, but maybe both are obsessive in this case?) Thank you again.
Thanks for contacting the Toronto Master Gardeners.
The best way to help your 15-20 year old “willow shrubs”,[either Salix integra ‘Hakuro Nishiki’ or possibly Salix purpurea ‘Nana’ (dwarf blue leaf Arctic willow)] keep their vase-like shape is to first of all, determine how tall you want the shrubs–are they specimens or do they form a hedge? In the case of ‘Hakuro Nishiki’, how much colour you want?
These willows can, as you know, either be trimmed back in the late winter or be coppiced to the ground to encourage new, colourful growth.
“Nishiki’ willows take to pruning and shearing very well, to either promote good color or maintain a manageable size. Pruning should be done while dormant, in either early winter or VERY early spring before catkins appear and any growth begins. You may hard prune it down to about 12” every few years, which will produce a lot of regrowth and a very dense plant. If you prefer a more open and natural form, simply remove up to one third of the branches down to the ground each year or two. By thinning rather than shearing you will have an 8-10 feet tall and wide, elegant fountain of gorgeous variegated foliage. Or shear as needed to maintain size, or every 4-6 weeks to produce new colorful growth.
Eventually your dappled willow (shrub form) will develop thick central branches that become trunk-like, particularly if you are not pruning hard every year. The old trunks no longer turn red in winter, but do produce many, many branches that turn red. Growth will be dense to the ground, or you can remove branches up a length of each trunk, resulting in a multi-stemmed semi-tree form. Maintenance pruning is generally necessary as twigs develop up the length of the bared trunks. If there are too many main trunks, a few may be pruned out completely depending on the form you desire”. See article.
As you mention, it’s best to prune or cut back in the late winter or early spring. Willows are basically low-maintenance plants that respond well to pruning and reward one with good colour and shape.
We hope that this information will help you decide how to maintain your ‘willow shrubs’.