Consulting Rosarian Tip for July

Rose Garden Tasks During July and August
By Barbara Kemp, Master Rosarian


June rains enhanced the growth of our roses. Roses were strutting beautiful first blooms at the mid-June Denver Rose Society District Rose Show.


Here are some tasks during the hot summer months:


As temperatures rise in July and August, watering will be a priority to maintain healthy, beautiful roses. Water is very important and roses will need additional water, approximately one inch of water each week for mature, large roses. Don’t forget your miniature roses, they will also need to have sufficient water. The best time to water is early morning when temperatures are lower. I water each rose by hand twice a week.


Roses will be ready for deadheading, pruning as needed, and the second fertilization around July 4 and then the last fertilization by end of August. For each rose bed at my house, deadheading and fertilizing roses are combined. Water roses the day prior to fertilization. When using granular fertilizer, the mulch is raked aside to scratch the granules into the soil. Water is applied again and then threetofour inches of new mulch are added to maintain a constant, cool temperature during the hot months. Gorilla Hair Mulch is my favorite as it stays in place when watering.


When one-time blooming shrubs and most climbing roses are finished blooming, prune out weak inner growth to maintain airflow within the bush, or shape roses as needed. Remember to seal canes with colored nail polish or wood glue.


Integrated Pest Management (IPM) is monitoring roses for pests and diseases early to resolve problems. I have practiced IPM for a couple of years and have resolved problems with pests and diseases without using chemicals. Chemical controls are used as a last resort beginning with the least toxic. Evaluating and note-taking from year to year will help determine what works best in your garden.

If you need to apply chemical sprays for pests and diseases, water roses well before spraying to prevent damage to leaves. Spray early on cool mornings with no wind to drift sprays onto other plants or animals. Read labels and guidelines thoroughly for safety precautions regarding appropriate dress (long sleeve shirts, pants, and using rubber gloves) and headgear (respirator mask).


Below is helpful information for eliminating insects and diseases without spraying.


If you notice flowers with tiny punch-like holes, check for an insect, Rose Curculio, a brown snout beetle with a piercing beak. I usually catch and squish it. If you are not quick enough, it will fly to another leaf or bloom.

Powdery Mildew (fungus) will begin to appear on my rose, ‘Zephirine Drouhin.’ Some leaves will have raised blister-like areas with a rumpled appearance on the upper leaf surface. More severe powdery mildew will have distorted leaves and buds covered with white talcum powder-like growth in which leaves may curl and drop off. Strong sprays of water will help with early detection; otherwise a fungicide can help eliminate powdery mildew.

Monitor roses early mornings and late afternoons for Japanese beetles (JBs). I pick off my beetle friends and put them in a ziplock baggie filled with soapy water, journal the count, and then ZIP it shut. Last year I collected about 260 JBs.


Enjoy the Beauty and Fragrance of YOUR Roses during the Summer Months


Dave Ingram, Arvada  Bee’s Knees