MANHATTAN, Kan. – Hybrid roses can be picky, as well as prickly plants. Give them exactly what they want, and they’ll bloom like a beauty queen. Thwart them, and you’ll risk getting pay-back.

Most roses, for example, prefer their annual trim after the danger of killing frost has passed – but before their new growth appears in spring, said Ward Upham, Research and Extension horticulturist at Kansas State University.

Missing that timing or pruning incorrectly increases the risk of cane canker – a fungal disease that can invade through pruning cuts and weather damage and kill an entire cane in a single season, Upham said.

"Winter’s cold temperatures may have killed rose canes back further than usual. Even so, some canes may have died or been especially vulnerable to cold because of disease. So, you need to remove all dead and diseased-looking material, pruning below the margin of the discoloration," he said.

Upham recommends using sharp shears and making pruning cuts at a 45 degree angle, about one-quarter inch above a healthy bud.

"If you’re dealing with shrub or climbing roses, that’s all you need to do now. For them, any additional pruning should come after they’ve flowered," he said.

But hybrid teas, floribundas and grandifloras need more springtime care, the horticulturist added. The pruning "style" used can reflect any one of three specific goals:

To produce large, showy flowers on well-established, vigorous plants – Remove all but three or four healthy canes. Trim the remaining canes down to 6-12 inches in height, so that each has just three to six buds.

"If winter’s damage was severe, rose owners may have to adopt this style in the extreme, just to get rid of dead plant material," Upham said. "So long as some inches of healthy green cane remain, however, the rose will try to come back – and may very well succeed."

To increase the number of flowers produced by well-established, healthy plants – Cut away all but five to six healthy canes, which you prune down to 12-18 inches tall, leaving at least seven buds for each.

To give a plant a new start, whether it’s a newly established bush or the victim of years of neglect – Prune away all but five to seven healthy canes that are 18 or more inches long.

"These approaches come down to severe, moderate and light pruning," Upham said. "The first benefits the flowers most. The last maximizes leaf area, so the plant concentrates on producing energy and becoming stronger."

The horticulturist recommends feeding established roses after pruning. As with other crops, getting a soil test done before applying fertilizer is a good idea, to ensure the soil doesn’t build up too much phosphorus.

"Although most soils in Kansas are naturally low in phosphorus, repeated applications of fertilizers with this nutrient can lead to high or even excessive amounts. And, excess phosphorus can interfere with roots’ ability to pick up certain micro-nutrients roses need," Upham said.