April 29, 2013

To prune or not to prune?


---- — PLATTSBURGH — For gardeners who neglected to prune their rose bushes last fall, now is the optimum time to make up for it. 

“Roses bloom on the new growth, that’s why you cut it back,” said Amy Ivy, executive director of the Cornell Cooperative Extension in Clinton County.

“You cut it back to concentrate the plant energy. In the spring, it pushes out that new growth, and that’s where flower buds are formed.”

If you don’t trim the canes back, the plant will flop.

“It will live and not be as attractive,” Ivy said. “It’s not too late to prune it now. The one time to not prune is in the springtime when the shoots come out really fast. The leaves are coming out and the shoots are expanding during the first two-week period. You prune before that period or after. Where the leaves come from, they have been there since last September. In the spring, they swell and get bigger and get ready to grow. That’s where the shoots come from.”

Pruning roses is time-sensitive.

“Pruning things like roses before these buds grow will direct the energy to all this new, vigorous growth. If you go ahead and let it grow, it’s going to put energy into that growth. Then if you prune it, you will be slowing down the plant,” she said.

Letting the plant grow and then pruning is a good approach if a rosebush or other type of bush is too vigorous or too big.

“You want to slow them down,” Ivy said. “Pruning after they leaf out helps to maintain them. It’s kind of like a calming, stable thing as opposed to pruning before they leaf out. That invigorates. Because you want a lot of flowers, you usually want to invigorate the plant.”

Ivy advocates ruthlessness when cutting back the bushes to about 2 feet tall.

“The bella rugosa, cut back maybe 24 to 20 inches. Those are so big. You can only go back so far with them. Spring is actually the best time to do it. Pruning in fall can give the plant the wrong signal,” Ivy said.

Because pruning invigorates the plant, it may start growth processes again.

“You want it to get tough for the winter and shut down and be dormant. Waiting to prune in March or April is ideal for roses,” she said.

Feed the pruned plant after it leafs out. 

“It invigorates the plant with nutrients,” Ivy said. “You can put that on in May. You can use a granule or a couple of inches of compost under the plant. Because they grow so much, you want them to flower to get all these beautiful flowers. Giving them some food will help them to be robust and flower better.”

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For more tips on pruning roses, search for "An Introduction to Pruning Bush Roses" with Paul Zimmerman at