Monday, May 25, 2009

Rose Deadheading: A Cut Above...Or Below

A sure-fire way to have repeat blooming, hybrid tea roses in full flower for your next big get-together at the house: deadhead them six weeks before the event. The problem is, the process of removing those spent rose blooms can vary, depending on which rosarian you talk to. For example, Jane emails us: "Would you please tell me the deadheading method recommended by the Sacramento Rose Society?"

         Many rose sources would offer advice such as: cut off the spent flower shoot down to at least the first leaf with five leaflets, preferably just above an outer-facing bud, to encourage growth away from the interior of the plant.

         Of course, when talking with rosarians, techniques may vary. Anita Clevenger, a Sacramento County Master Gardener and member of the Sacramento Rose Society who also helps maintain the historic rose bushes at the old Sacramento City Cemetery, has an interesting take on this process.

"It's still my belief that roses will rebloom quicker if you leave the leaves and canes," says Clevenger. "Nutrients are stored in them, and leaves are needed to produce the flowers.  If you deadhead down to the first outward-facing five-leaflet cluster, as is usually advised, you cut off quite a few leaves. The plant will first grow new canes and leaves before setting flower buds. A rose from which the spent flower has been snapped will also grow a new flower stem, but it will be shorter." 

          Clevenger also thinks that snapping off a spent rose flower, instead of snipping, can mitigate pest problems. "I believe that there are less cane borers as a result of this process," she says. "Borers invade a cut stem. It's also possible that there is less risk of spreading disease. I once ran across an article that claimed one got more and stronger basal breaks (new flowering wood) as a result of just snapping off the spent flowers. The theory was that the plant was stronger because it had more canes and leaves."

          Aesthetics may argue against this technique. "On cluster-blooming flowers, such as polyanthas and floribundas, the new growth will probably come from below the flower cluster, which will die and remain visible," explains Clevenger. "Some people think these dead clusters are ugly, but they don't bother me much, and I'm willing to go back and trim them off after the rose has decided where new growth will emerge. Another aesthetic objection can be based on the fact that a plant will grow bigger and taller.  If you want the plant shorter, deadheading decisively is a way to attain that. Also, if you want a long-stemmed bloom, snapping off the flower won't achieve that.

What you do can depend on the specific rose. "Some experts dispute the idea of deadheading, or pruning, to an outward-facing bud," says Clevenger. I have observed that the a rose will probably put out growth from two or three buds below the pruning cut, and often the second bud yields the stronger growth. Their recommendation is: prune to the height and shape that you want. Deadheading can be a form of pruning, so the same advice applies. Once you get to know your roses, and your preferences, you can figure out what works."

         And perhaps that is the bottom line: when it comes to deadheading what works for you.