Plan for hot, less-than-ideal conditions for roses

Once again, I'm reminded of unusual weather. This past year Temecula Valley temperatures seem to track similar to the last three years. To date, the number of days when temperatures were 100 degrees or more are about the same with the average being similar for 2014. The fact is, there's a “new normal”, but we don't have a clear idea of what that is going to be. The best guess is greater extremes with less predictability.

This year too we've had an odd summer: shorter periods of high temperatures and an usual amount of nominal rain over several days. All told, this summer hasn't been too harsh on my roses, and I've gotten reports that some local gardens had a nice show of blooms into July due to short hot periods. Others report a lot of sunburned blossoms and stems, the result of the plant being unable to hydrate at the same rate as its evaporation. I advise you to leave as many leaves on the plant as possible during this time of year as protection against sunburned canes. Sunburned canes can cause death to the rose plant.

That's why I still advocate planning for higher temperatures and less-than-ideal conditions for roses. Let your roses continue their summer dormancy until about mid-September. Why make them produce blooms when they're struggling to stay hydrated?

Let your roses 'do whatever they do'. That is, just remove and discard the withered petals and let the hips develop, keep the bed clean of debris, and don't fertilize. Twice a week, give your HTs (Hybrid teas) a deep, slow watering of three gallons of water. Take an investigative stroll through your gardens in the morning and look for leaf wilt, drying or discoloring of leaves, and the general leaf reflectance (surface luster). If it appears dull, investigate the plant for disease, drought or pests.

During you daily tour of your garden, look for any changes. It doesn't take long for a rose to suffer once its irrigation supply fails. Examine the lower leaves. If they appear yellow or brown, have fine webbing and/or look dirty, there may be an infestation of spider mites.

Spider mites thrive in hot weather and are generally found on the undersides of those lower leaves. A quick check can be made by lightly running your fingers across the underside of the leaf. If it has a small grainy feel, it most likely is the spider mite.

A strong spray of water from below followed by an overhead shower should take care of the problem or at least hold it in check. Give the shower early in the day so the plant has time to dry before the sun becomes hot. Do this every three days for 10-14 days, inspecting regularly. It may be necessary to repeat after a few days if the infestation is heavy. Removing the bottom leaves approximately 8” from soil level can help in reducing to eliminating the spider mite problem. This should be done earlier, prior to an infestation.

The world is dangerous enough for plants, but we gardeners are also faced with risks. One recently came to my attention through a Dr. Gott. It's a dangerous fungus with the scientific name Sporothrix schenckii. It afflicts humans with the fungus infection sporotrichosis. It is often referred to as the Rose Thorn (or Rose Gardener's) Disease.

The fungus resides on hay, sphagnum moss, the tips of rose thorns and in soil. It can cause infection, redness, swelling and open ulcers at the puncture site. The fungus can also spread to the lymphatic system and move on to the joints and bones where it ends up attacking the central nervous system and lungs when the thorn or thorns are deeply embedded.

A relatively uncommon condition, diagnosis can be complicated. Physicians often mistake it as staph or strep infection. If you suspect this condition, be sure to inform your physician that you are a gardener so appropriate diagnosis and treatment are rendered.

If you have been following my summer protocol for growing roses, you should have rose hips and few blossoms left on the bushes. Otherwise, a semi dormancy period. Soon you will want to “wake” the rose bush up again for a couple bloom cycles yet in the year. Between mid-August and mid-September a small pruning should be done, but do not remove more than a third of the current growth.

Around the first of September to mid-September, begin fertilizing again with one higher in phosphate – the P in NPK rating. Most organic fertilizers don't use this obvious rating. You will need to read the packaging information which will be in percentages. In either case look for something similar to 8-10-8.

We all enjoy the fragrance and beauty of roses, and have often had our skin pierced by thorns (“prickles” is the correct anatomical name). Good protective measures include wearing appropriate clothing (gloves, long sleeves, or gauntlets) when working among roses and thoroughly cleansing even minor scratches and punctures with an anti-bacterial soap. Rubbing alcohol – which you should already have handy to clean your pruners – can be applied as an immediate wash until you can use anti-bacterial soap. Anything more than a minor puncture should be watched carefully for signs of infection; seek medical attention as soon as possible if you show any of the signs described above.

Even the simple things in life have risks, so take precautions so you can stop and smell the roses. And when you've got a moment to spare, go visit Rose Haven, located at 30592 Jedediah Smith Road (the cross street is Cabrillo Avenue) in Temecula. Also, visit our web site, http://www.TemeculaValleyRoseSociety.org.