By Joyce Karsnak
OSU Ext. Master Gardener Volunteer
Most folks have heard the term “pinching” garden mums — a form of pruning with your thumb and index finger to remove the growing tip and first set of leaves of each shoot to encourage branching and a fuller plant. You can begin pinching when the plants are about 4 inches tall and again a few weeks later.
But if you are like me, you haven’t gotten around to it and now the plants are too tall and spindly and already have buds. That’s the time to pull out your pruners and cut them back about one-half. Then again, a few weeks from now, give them a little pinch, but not after mid-July. They need time to grow the buds to flower in the fall.
Extending bloom time
Pinching or selectively cutting back can extend the bloom time and improve the appearance of many perennials, those with a branching habit such as salvia, or those that tend to grow tall and then want to flop over. To extend the bloom time of Shasta daisies, I pinch some of the buds in a random pattern, usually at the beginning of June. When my salvia has passed its prime bloom, I cut back the flowers to the next set of lateral stems, or if it’s getting too large for the space, back further to a lower branching section.
The natural cycle of the plant is to flower and then produce seed. Removal of spent blooms keeps the plant thinking it needs to produce more flowers. On perennials, the next blooms might not be as large or as profuse as the first flush, but it is well worth the effort to have extended color in the garden.
Use the same principle to keep your annuals blooming, often referred to as “deadheading.” When the snapdragons have gone to seed, cut the seed heads off and before long you’ll have another round of blooms. Are your petunias in hanging baskets looking nasty but still living? Give them a shearing and some nutrients and they’ll rejuvenate. Snip off dried zinnias and marigolds and they’ll continue to produce flowers until frost.
Pinching, cutting back and deadheading are great ways to extend bloom time and keep your gardens looking fresh throughout the season.
More information can be found at http://pubs.cas.psu.edu/FreePubs/pdfs/xj0040.pdf