Early flowering shrubs are what makes springtime in Philly so magical. For a few short weeks our area is lush with the blooms of spirea, lilac, viburnum, mock orange, forsythia, and ornamental quince. Fast forward to the cusp of summer, and the charms of these one hit wonders are all played out.
Now what? These shrubs that a few months or weeks ago sent hearts fluttering are now drably arrayed until next year. And they’ll continue to grow.
If you have a mature garden you may have already battled an Old Ironsides of a shrub that has become too large for its surroundings. Stems spread and sucker, as upper branches reach for the light, fail, and flop over. Lilacs, in particular, can become so tall that it’s difficult to enjoy the flowers, arguably the only desirable feature of the plant.
But it is possible to get the upper hand with these plants, and now is the time to do it. The easiest method, and the one that gives the most natural results, is to fight your way into the center of the shrub with a strong pair of loppers or a pruning saw. Identify the oldest, thickest stems and start cutting them off close to the ground. You can remove up to one third of a plant this way, and it can be done every year. After three years you will have a completely rejuvenated, much smaller version of the plant you started with, one that will assume a much friendlier presence in your garden.
There are some exceptions to spring blooming shrubs that can be treated this way, namely tree peonies, roses, pieris, rhododendrons, and azaleas. These plants demand more careful shaping and good timing. But the mantra for all other shrubs that have finished blooming? Whack them back (just don’t give yourself a heart attack.)