Summer is the time of year when short shorts rule, blue skies reign and outdoor activities dominate the weekend. Gardeners hale the season in by spending more time in the garden. But when it comes to roses, summer weather can create some stressful conditions for plants, including heat and water stress, foliar diseases and hungry insects.
Try these summer rose care tips to reduce summer stress for roses.
Q: Do the warm days and cool, damp nights pose any problem for roses?
A: But moisture on the leaves and the flowers under those conditions will encourage foliar diseases and flower problems.
None of us can stop the rain, but we can plant our roses where there is good sunlight and air movement. During the summer, avoid water on the foliage as much as possible and always keep the area around your roses free of plant debris. This will reduce the chances of any diseases being splashed onto the foliage.
Q: How often should roses be watered in summer?
A: Because we live in the rainy Pacific Northwest, many gardeners think that their roses don't need a lot of water. However, during the months of June through August, roses are often thirsty for water. Be sure to water your roses at the base during these months. Established roses need 2- to 2.5-inches of water once a week during the summer months.
Keep in mind that soil, temperature and surrounding plants do affect how much water a rose needs. In temperate climates, weekly watering is usually enough; two inches of water a week may be all that is needed. If the soil is sandy or the garden is hot, dry or windy, more frequent watering may be necessary.
Q: What's the best way to tell when roses need to be watered?
A: A great way to check if the roses need water is to scratch around the base of the plant and outside the "dripline" of the rose about 2 inches to 3 inches deep to see if the soil is dry. If it is dry, then water; if it's wet, wait a day or two to water again. The active feeder roots are not going to be near the crown of the rose, but rather out and away from the "dripline" of the rose.
Q: So then, what method do you recommend when watering roses?
A: The best way to water roses is to provide a nice slow soak so that the water goes deep into the soil profile. Roses can have feeder roots as deep as 12 inches and will need water to keep those roots alive and well. Watering deeply in that area all around the plant will help your rose healthy and beautiful. Do not sprinkle the foliage if at all possible. Wet foliage encourages leaf spots and disease problems. Watering from overhead can also damage the flower buds and reduce the beauty of your roses.
Q: It sounds like drip irrigation or soaker hoses are great way to water roses. What about sprinklers?
A: Many gardeners set their automatic sprinklers to water their roses heavily when the plant is young. However, they often forget to adjust their sprinklers when the plant is older and established. This causes wet or soggy feet for the roses. Established roses should be watered when they need water and generally not on a "sprinkler system schedule." This is problematic for the myriad of people who now set the timer and walk away.
Q: Summer weather and insect problems often go hand-in-hand. Any organic methods that you recommend to control pest insects on roses?
A: With many gardeners also growing their vegetables near their roses, we recommend using organic ingredients to tackle common Pacific Northwest insects that attack roses. There are many products on the market along with predatory insects that can be used to get rid of damaging insect pests. The first thing to understand is you have to determine at what threshold you are ready to get rid of the insects. Are you okay with a few aphids here and there or do you require your roses to be completely free of aphids? No matter how you want your roses to be, organically controlling the aphids will require patience and endurance.
Ladybugs are a great way to reduce aphids and there are several other predatory wasps that will also reduce the aphid population. The unfortunate side effect of investing in predatory insects is that they are not necessarily loyal to you as their owner. They may fly away and take care of your neighbor's yard just when you need them the most. A great way to seriously reduce the number of aphids attacking your plants is to use soapy water spray. Create a solution that is one part dish soap to nine parts water to take care of those critters. This solution will not cause damage to you, your animals or your plants.
Q: Should we deadhead spent flowers regularly? And what's the best way to deadhead?
A: Deadheading seems like an awful lot of work, but it is well worth it. Once the blooms have completely opened and the petals are just starting to fall or when you think the flower has pretty much finished being a good flower, it is time to remove them. In order to get another flush of flowers that are as big and wonderful as the first flush it is important to prune them off correctly.
The best rule of thumb is to go down the stem until you find the first leaf with five leaflets. Make your cut just above that leaf and a new shoot will soon appear with a rose bud on it. The more often you deadhead the prettier and tidier your roses will look.
There are some rose types that have self-cleaning flowers and it is not necessary to deadhead these. If you want to enjoy the varied colors, sizes and shapes of rose hips throughout the winter months, do not deadhead the last flush of flowers and they will produce an abundance of rose hips for you to enjoy and will be food for the birds.