Prunus triloba ‘Multiplex’
This is an excellent ornamental shrub with showy pink blossoms in late Spring. It is very common throughout Alberta, and looks great as a specimen in a shrub bed complimented by a variety of perennials. We encounter this shrub frequently, but unfortunately, it is seldom in good shape. The majority of specimens are either neglected or butchered, and sometimes not salvageable. Ironically, this shrub is hardy, easy to manage, and needs only minimal maintenance pruning to look its best.
Dormancy from late Fall to mid-April is best. It is pruned as if it were a miniature tree, so in order to prune it properly you have to be able to see the framework of branches.
I prune this plant as I would other trees and shrubs in the Prunus genus. I treat it like a miniature chokecherry, which means I get on my hands and knees and work on this shrub first from the base, removing suckers, and then up each major branch, removing deadwood, crossing and rubbing branches, and disease. I like a plum that flows up and out from the centre of the shrub. Each major branch (or “system”, as we call them) must have its space. Remove inward-growing branches. To balance the form, reduce or remove wayward limbs. Remove fast growing sprouts from the main branches. These are easy to spot because of their light golden colour. The completed shrub should look like a small multi-stemmed tree, with a clean, flowing appearance, and balanced form.
Crown Reduction and Shaping
This plant is not suited to shaping by shears or power hedgers. Avoid shaping this plant. A proper crown reduction can be carried out using hand pruners and select reduction cuts to lower the height and decrease the width of this shrub. It requires a lot of skill and practice to pull this off and still have a nice-looking plant. I recommend that instead of trying to adjust the size of the plant, adjust the size of the bed in which it is planted.
(c) 2014 Shane LePage, Wild Rose Garden & Tree Service Inc., Red Deer, AB