Trimming Flowering Shrubs

From the moment the first forsythia began to bud out, I knew we were in for a fabulous showing of flowering shrubs this year. Thanks to the cooler temperatures we’ve had this year, flowering periods have been extended and we are able to enjoy the show longer than we do in warmer springs. But, as they say, all good things must come to an end. Some of the flowers have already faded and branches are beginning to leaf out; a sure sign of warmer days ahead.

Once the flowers have faded from spring blooming shrubs and trees, it is the ideal time of year to trim and shape them. Don’t leave this task too long or you’ll be sacrificing blooms for next spring.

Over the years I have seen some rather interesting trimming techniques; there are the “Tender Trimmers”. Those are people that merely snip off the dead flower heads, afraid to touch any other growing part of the plant (not recommended). Then, there are the “Hackers”. They chop away at the plants willy nilly with no thought to shape or growth patterns (also not recommended). There is the “Plant Perfectionist” who will literally spend hours on one shrub (okay if you have the time, but really doesn’t make that much difference unless you’re maintaining a topiary).

Ideally, you should be able to trim and shape an average sized shrub in fifteen minutes or less. Using sharp hedge shears (can’t emphasize that enough), begin removing the dead flower heads. You’ll take a few leaves off with them, but that’s expected. Then, take a look at the inside of the shrub. Remove any deadwood by cutting it out at ground level using sharp loppers. If the centre of the plant is thick with branches, thin out the crowded growth. This allows for better air circulation within the shrub which is your first defence against plant diseases. It also encourages the shrub to sprout new flowering shoots.

Now you can move on to tricking the shrub into growing where and how you want it to, not where Mother Nature wants it to. Start by trimming the top straight across using those very sharp hedge shears of yours. If it’s growing against a wall, cut the back of the shrub so it is not touching the wall. You’ll want to trim it so the bottom of the shrub is wider than the top by several inches. Cut back, a bit at a time so you don’t take too much off, the sides and front of the shrub. Again, the bottom should be wider than the top. We do that so the bottom leaves and branches will receive as much light as the tops portions of the shrub. That helps prevent the sparse, spindly look shrubs get at the base otherwise.

On to the top. Holding the hedge shears at a thirty to forty-five degree angle, trim the edges where the sides meet the top all the way around the shrub. You are almost done. Look the shrub over and do some light touch up trimming here and there to even out the shape. Using hand pruners, remove any leafless “sticks” (a.k.a coat hangers) jutting up throughout the plant by making a flat cut just above the first set of leaves on the stick. Should that first set of leaves face the inside of the shrub, move down the satlk to the next set of leaves that face the outside of the shryb.You’ll give the shrub a well groomed look by doing that and direct the growth towards the outside of the shrub. On a personal note, it drives me to distraction when I see a shrub that hasn’t had the coat hangers removed.

Fertilize the shrub by spreading composted manure about one inch thick around the dripline of the shrub, or use a balanced, water soluble fertilizer. Add mulch to the bed and you’re done!

One final hint: Sterilize the shears, loppers and pruners in a mix of three parts water to one part bleach after trimming each shrub. If there are any diseases on the shrubs, you’ll be less likely to spread those diseases between plants by doing so.