Consulting Rosarian Tip for March
Rose Garden Tasks During Summer Months
By Barbara Kemp, Master Rosarian
Summer finally arrived the last week of June. The abundance of rain during June enhanced the growth of roses after being drastically pruned to the “ground” cutting out all
dead canes resulting from the cold winter temperatures. It was hard to imagine that roses
would come back with such resilience and beauty after the hard pruning, harsh rains, and
hailstorms. Roses are strutting beautiful blooms and growth, so here are some reminders
for the summer months.
Water: As temperatures rise, watering should be a priority to maintain healthy, beautiful roses through the
summer months. The amount of water during July and August with 90 plus temperatures should be about one inch of
moisture each week for a mature, large rose. To determine the amount of moisture in the soil, use a soil moisture
tester, which can be purchased at garden centers. You can also use a spade to dig down two-to-three inches to test the
soil. If soil is crumbly, it is dry and needs water. Be sure to water in the cool mornings or late afternoons for better
water absorption and to avoid burning the leaves.
Deadheading, Pruning, and Fertilization: Roses will be ready for both deadheading and the second fertilization around the Fourth of July 4 and then the last fertilization by end of August. For each rose bed at my house,
deadheading and fertilizing roses are combined. When using granular fertilizer, the mulch is raked aside to spread
fertilizer and then scratch the granules into the soil. Water is applied again and then three to four inches of new
mulch, as needed, to maintain a cooler temperature during the hot months.
When once blooming shrubs are finished blooming, this is a good time to prune out weak inner growth to
maintain air flow within the bush or shape roses as needed. Remember to seal canes with colored nail polish or
wood glue.
Integrated Pest Management (IPM): Integrated Pest Management (IPM) is regular monitoring and resolving
your rose problems using chemicals as the last resort. I have used IPM for a couple of years and have resolved problems without using chemicals.
If you must use chemicals for insects or diseases, read the labels carefully. Apply when temperatures are below 80
degrees with no wind to drift onto other plants, animals, or people. Water roses well before spraying to prevent damage to leaves. Also, dress appropriately wearing rubber gloves, long-sleeved shirts and pants.
Insects and Diseases:
• If you have aphids or spider mites, use strong sprays of water daily until they are gone. For spider mites direct
the spray from underneath.
• Thrips are tiny insects that cause damage to the petals. The damage from thrips is recognized when buds remain
closed, are bent over and/or turn brown. Remove and discard buds and infested flowers.
• If you notice flowers with tiny punch-like holes, check for the 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.
• 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 160 JBs.
Refer to Growing Roses in Colorado for additional information on IPM and insects and diseases.
Enjoy the Beauty and Fragrance of YOUR Roses!