Drought — we're in the midst of one that may influence the way we garden in the future. While recent drenching rains have eased the imminent threat, the potential for significant restrictions in future water use remains. What will that mean for your roses? Aren't they water hogs that need lots of water to survive?
The amount of water a rose plant needs depends on a number of variables, including the age, size and location of the plant, the nature of the soil it is growing in and the air temperature, humidity and wind conditions. While roses perform best with ample water, they can make it on much less; the plant may not grow or produce many flowers during the hot summer months, but they will survive.
Often watered frequently for short amounts of time, garden roses develop shallow roots and subsequently have a tougher time when there is reduced water availability. But it's not how they start out. Most modern roses are grown in production fields located in hot areas such as Bakersfield and Phoenix. They are deeply watered only once a week (furrow irrigation for about half a day), no matter if the temperatures are triple-digits range for weeks. And they do just fine.
To maximize your water use and keep your roses healthy, consider these tips:
- Smaller may be better: After the big spring bloom, trim plants back to reduce their overall size. The more foliage on the plant, the more water it will require to remain healthy. You may lose some bloom, but come fall with its cooler temperatures, you should get a good crop of flowers.
- Go light on fertilizer: Many rose growers apply high nitrogen chemical fertilizer monthly spring through early fall; this stimulates growth requiring the plant to use more water. And the resulting succulent new foliage is attracts aphids. If you fertilize, try a less soluble form of nitrogen and apply it in small portions throughout the season. Organic materials, such as manure, fish emulsion or blood meal, or slow-release fertilizers fill the bill. Or think about reducing) the aphid cycle this season and don't add any supplemental fertilizer.
- Timing can make a difference: Water during the early morning hours when temperatures and wind speed are the lowest, and stretch the time interval between irrigations where possible. Roses do best when 50 percent of available water is depleted between irrigations.
- Check your tools: No matter what system you use to water your roses, make sure they're in good working order.
- Technique makes a difference: To encourage your roses to develop deep roots, water your plants slowly and deeply; apply water only as rapidly as the soil can absorb the water. Divide your watering cycle into shorter periods to reduce runoff.
- Mulch, mulch, mulch: By adding a layer of mulch to the soil in the spring, you can moderate soil temperature, reduce water consumption and reduce weeds. The amount of mulch you add depends on the texture and density of the material you're using. A good rule of thumb is to add two to four inches of mulch.
- Watch out for weeds: Weeds will compete with your roses for precious water.
- Protect against pests: Spider mites thrive in dry and dusty conditions. During the hot days of summer, the insects can defoliate a rose plant in short order. Forceful spraying of leaves, especially the undersides, is a good method for keeping their populations at a tolerable level.