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This Pink Promise rose needs pruning. (Photo: Debbie Arrington)
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Some roses just don’t know when to give up. They keep blooming and blooming – and never go dormant.
In Sacramento, our unseasonably warm weather is prompting roses to break bud (sprout new growth) several weeks early and start blooming all over again – before they ever were pruned.
What’s a procrastinating gardener to do? Prune anyway.
Traditionally, Sacramento’s pruning season lasts until at least Valentine’s Day. But with so much warmth, the pruning window is closing rapidly (but not totally shut).
With this February feeling more like April, bushes are ready to go into high gear. Many appear to have jumped straight into full bloom.
The problem? New growth comes on top of old growth. The bushes will keep getting taller and taller – until summer roses will be way out of reach. What fun is smelling your roses if you need a ladder to sniff the blooms?
In addition to height, roses tend to sprout crossing canes in the interior of the bush. That growth becomes a thicket of prickly stems. That cuts down on air flow in the center of the bush, which can lead to fungal infections. That thicket is also prone to dieback, which can threaten the health of the bush.
Rose bush dieback most often can be traced to inconsistent irrigation, a common byproduct of drought. Roses, which are relatively drought tolerant once established, can suffer from lack of water – especially during or right after high-growth periods such as now. Roses – particularly those growing in full run or in containers – also can be susceptible to dieback during intense summer heat. Again, that’s linked to inconsistent water as well as temperature.
A bush may look full and healthy, but its foliage may be hiding problems underneath. An example is this Pink Promise hybrid tea. As of Feb. 6, it was nearly 10 feet tall and sporting more than a dozen blooms. The dark green leaves looked healthy and nearly covered the entire bush. It was very tempting to just let it grow.
But once removed, the foliage revealed a tangle of dead stems in the bush’s interior. Removing that dead wood will assure healthier new growth this spring.
When late pruning, concentrate on removing that dead wood and improving air flow. Height-wise, prune “taller.” Bring hybrid tea and grandiflora bushes down to four feet tall (instead of three feet or less); floribundas to three feet (instead of two). Shrub roses, which tend to sprawl out instead of up, may need only a little light shaping.
As for last season’s remaining leaves, strip them off this week if you can. That foliage likely is full of fungal spores (particularly powdery mildew and rust). These 70-degree days will reactivate those fungal diseases and they’ll quickly infect the new growth now emerging.
Also, rake out any old leaves under the bush and apply fresh mulch. That will help cut down on fungal disease as well as maintain consistent moisture during dry months to come – cutting down on dieback.
Once fresh growth appears, feed roses with a balanced fertilizer, then feed every six to eight weeks through spring and summer. This TLC will reward you with months of blooms.
For more on roses and rose diseases, check out these pest notes from the UC Integrated Pest Management Program:
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7463.html
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