It’s obviously important to prune trees – and I’ll explain why below. But it’s also important to know when to prune.
It’s a truism that the best time to prune is late winter and early spring, when trees are not susceptible to a freeze but before the buds begin to swell. But this does not apply to all trees! Three species you should not prune when dormant are Acer (maples), Betula (birches), and Ulmus (elms).
Be kind to your maple, birch and elm trees. Only prune them when they are in full leaf, so they don’t bleed. Mid-June through July is the best time to prune maples and birches — not earlier. Why? When do people tap maples to get syrup? When they are dormant, because that’s when the sap runs. Yes, syrup is also made from birch trees. Depending on the variety and location, their sap generally starts to flow a bit later than maples.
