Gilman, E.F., G.W. Knox, and P. Gomez-Zlatar

Pruning method affects flowering and sprouting on crapemyrtle
Journal of Environmental Horticulture 26 (3): 164-170

'Natchez' (Lagerstroemia indica x fauriei) and 'Carolina Beauty' (Lagerstroemia indica L.) crapemyrtle were pruned in three manners including topping, pollarding, and pencil-pruning plus a non-pruned control for four years to determine influence on flowering and sprouting. The topping and pollarding of 'Natchez' delayed appearance of the first flower up to one month compared to non-pruned trees for the first two years following initial pruning. In contrast, topping and pollarding 'Carolina Beauty' induced flowering by as much as one week sooner one and three years following initial pruning with no effect in years two and four. Topping both cultivars delayed peak flowering date compared to non-pruned trees. Topping 'Natchez' the first and second year following initial pruning and pollarding in the second year reduced duration of flowering period compared to the non-pruned trees. Flower effect (panicle number x panicle volume) was not influenced by pruning method on 'Carolina Beauty' for any year. Flower effect for topped 'Natchez' was significantly smaller than for pollarded and pencil-pruned trees the first year after pruning; flower effect on non-pruned 'Natchez' was no different from any of the pruning treatments. Pruning cut diameter was inversely correlated with number of days 'Natchez' trees were in flower, number of flower panicles, and date of flowering; however, cut diameter influence on flower effect was not predictable for 'Carolina Beauty'. Sprouting along the trunk and from the roots increased with diameter of pruning cut. Topping took less time to complete than other pruning methods in all but the last year which probably accounts for its popularity. Topped trees grew in height following pruning faster than pollarded trees, which grew faster that pencil-pruned trees, which grew faster than non-pruned trees for both cultivars.

Click here for full article (PDF file)