The mulberry genus, known botanically as Morus, is made up of deciduous, flowering and sometimes fruiting trees and shrubs. Mulberry trees are either a red cultivar called rubra or a white cultivar called alba. According to Ohio State University, mulberry fruit resembles blackberries in appearance and is used interchangeably with blackberries in recipes and for fresh eating. The trees flower in May and the female trees produce fruit in July and August. Timing of trimming is particularly critical to preserve the fruit harvest, if that is of principal interest.
Trim your fruitless male mulberry tree in the winter or early spring when the tree is dormant and there is no new growth visible. You can also trim fruiting mulberry at this time if you do not wish to harvest the fruit or do not mind a diminished fruit crop.
Trim fruiting mulberry trees in the late summer or early fall after the fruit harvest or after the birds have cleaned the tree of fruit.
Prune away any broken, dead, abrading, cracked or otherwise ailing branches from the tree. Place the cut back to the point where you find healthy tissue or down to the parent branch just outside the slightly swollen branch collar where the two branches intersect.
Cut back the tips of the terminal branches on the perimeter of the canopy to the desired length, removing as little as necessary to suit the site and landscape. Place all cuts on the bias and just 1/8 to 1/4 inch above a leaf node or bud. Work around the tree evenly and follow the natural form of the canopy to ensure a professional and gently symmetrical result.