October CR Advice, Barbara Kemp, Master Rosarian
This year has passed quickly. Here we are in October where trees are turning brilliant colors, roses are producing
beautiful orange and yellow rose hips, and bees are seeking out the last rose blooms of the season.
The hardiness of roses varies and some need extra care as the cooler temperatures begin. Here is some fall advice
Monitor roses for lingering diseases like black spot and powdery mildew, and spray with a fungicide like
GreenCure®. Dave Ingram has a great article “Poor David’s Almanac: A Few Clues about Powdery Mildew.”
This article is a 2018 Award of Merit Winner and previously appeared in the Denver Rose Society’s newsletter.
It also can be found on the ARS web page at www.rose.org.
Keep watch on weather predictions for any unexpected freezes, and water your roses prior so that roots are hydrated before the freeze. Also be sure to clean up rose beds before winter. The Front Range experienced its first
snow storm a couple of days after Labor Day. I took Dave Ingram’s advice and watered all roses the day before
but ran out of time to purchase the mulch to protect roses, so used burlap strips and placed them around the base
of tender roses (HT and grandifloras). I covered first year plants and other roses that had a lot of buds ready to
bloom. All roses came through two inches of snow with just a couple of broken branches/canes. Roses perked
up with beautiful blooms as the warm weather began again. Since there were no rose events this summer, a lot
of attention was given to roses making them healthy through scheduled watering twice a week and scheduled
fertilization throughout the summer which resulted in great foliage and minimal disease. I had two new companion plants: a cherry tomato plant that grew over a rose and a Canna Lily that took over part of a rose bed/
Check the soil level on grafted roses to ensure that the bud union is not exposed from soils settling during the
summer. After three nights of about 25 degree weather add adequate layers of mulch to keep temperatures constant during fluctuating weather conditions, and keep tender, less hardy roses protected for cooler temperatures.
Are roses pruned to a lower level to avoid breakage from winds and snow in the fall? This is a frequently asked
question. We do not recommend pruning in the fall, as it stimulates growth, and a hard freeze will kill new
growth and possibly cause severe damage to the rose. Wait until roses are dormant, and then evaluate pruning
down taller canes. Refer to winterizing roses in the DRS book Growing Roses in Colorado.
Fall is a great time to plan new beds or prepare existing ones for new roses in the spring. The Denver Rose Society’s recommended list of roses is a great resource to help choose the types of roses that are best for your garden and easy to grow in Colorado. The different classes of roses (hybrid tea, grandiflora, floribunda, etc.) are
summarized in Growing Roses in Colorado, and are helpful choosing color, fragrance, bloom cycle, disease resistance, hardiness in our climate, own root versus grafted roses, etc.
These questions may be helpful when establishing new rose beds: Will the soil need to be amended? Does the area
have proper drainage? And, is there enough space between roses for future growth and air circulation? You should
consider a soil test, which provides excellent information and can be obtained through the CSU Extension
Enjoy Fall in your rose garden.