I had my shears in hand Monday, ready to go through all the garden's formal plant elements and tighten them up - but as I stepped to the first plant I said to myself, "I don't need to spend an hour doing this now." It is/was early May, mid spring, and the new growth is just forming. This is the time to "shape" not trim. By this I mean, (this being a garden I was tending for the first time) it was a time to make heavier, deeper shear cuts to "address geometry," not manicure. Early in the season, plants will more aggressively push new buds in response to heavy pruning cuts, so this is the time for some deep disciplining. "Trimming" and "manicuring" is more of a maintenance practice to be done anytime. But this type of maintenance shearing is light and more about an immediate presentation of the garden than making the garden.
From Matthew Dore, the "I" voice of Buffalo Horticulture and "The Buff Hort Project."