Salix alba sibirica
Over the past few years, silver-leaf willow has become one of our favourite shade trees. While there are a handful of excellent mature specimens in Red Deer, it is still a very uncommon tree in our area. With the declining population of mature weeping and paper birch in Red Deer, due mostly to bronze birch borer, silver-leaf willow makes an excellent replacement tree.
Mature trees reach about 30′ in crown width and 30′ in height. Expect a growth rate of 4′ per year in suitable growing conditions. They are suitable for parks, acreages, and large front yards, taking up roughly the same amount of space as a mature weeping birch. The leaves are an interesting silver-grey-green, and the mature canopy has a distinct weeping form. We have not encountered any insect or disease problems on the young trees we’ve planted. The form and distinct foliage colour add an interesting contrast within the urban forest, and we consider the species highly under-planted.
Mid-summer through dormancy for structural pruning. Anytime for deadwood removal. As with most species, pruning is much easier, and better for the tree, when the leaves are off.
Train as a central-leader standard with well-spaced scaffold limbs, and reduce or remove co-dominant leaders. It is important to stake new trees for two seasons. We’ve found that the growth rate is so vigorous, that potted trees require additional staking, otherwise they will take on a significant lean away from the prevailing wind. Once the root system can support the crown, the stakes can be removed. Structural pruning is required at least once per season on fast-growing willow. We generally assess their structure in late June, and again in Fall.
Unsuitable. Allow a 15′ radius around or future growth, when deciding where to place the tree. Willow readily decays from large wounds.
(c) 2017 Shane LePage, Wild Rose Garden & Tree Service Inc., Red Deer, AB.