Is Getting Rose Bush Leaves Wet a Good or Bad Idea?

Disease

• When rose leaves get wet, the moisture helps existing fungal spores grow and thrive. Different types of fungus exist in most garden environments, but not all plants are susceptible; roses fall victim to several types of fungal infection. Wet leaves on roses can promote the growth of powdery mildew, blackspot and rust, for example. When these infections set in, the leaves might develop spots, turn yellow or wilt. They eventually fall off, leaving the plant unable to convert enough of the sun's energy to nutrients through photosynthesis, and the plant dies. Treating the plants for fungus can help, but it's best to nip the infections in the bud and keep them from developing by maintaining dry leaves as much as possible.

How to Water

• Soaker hoses make convenient options for watering your roses, which need up to 90 inches of water per year. These wind around the base of the plants in your rose garden and drip water directly onto the ground rather than sprinkling the water from above. When using a watering can or garden hose, water each plant individually and point the nozzle low to the ground rather than pouring the water over the top of the plant.

When to Water

• When you use options such as automatic sprinklers to water your roses, you can't control whether the leaves get wet. What you can control is the timing. Water your roses in the morning so the leaves have all day in the hot sun to dry out. Watering in the evening means the water won't evaporate quickly, which can give fungal infections time to get a foothold.

When It Rains

• Another thing you can't control is what time of day it rains or how often. There's no need to run outside with an umbrella to protect your rose bushes; planning their location carefully from the beginning offers some protection. They need at least five hours of sun per day, but most varieties enjoy full sun. When planted in full sun, they have more opportunity to dry out after a rainstorm than those in partial shade. Spacing the plants 3 to 4 feet apart allows warm air to circulate between the plants and promotes evaporation.