Normally, at this time of year, we would not expect to talk about something that would occur more in the cooler months, but we have been receiving a lot more gray days than sunny days recently. Plus, the over cast misty nights and mornings are lasting longer than normal. If you have been wanting to cut some of your beautiful roses recently and have been dismayed by ugly white stuff on your rose leaves, you are seeing the results of this muggy weather. Unless your particular rose variety is resistant, you have a very common fungus called Powdery Mildew.IIt shows up on roses and some other plants like Euonymous, Crepe Myrtle, and even cucumbers. The cause is cloudy humid weather. When the spores start to form they are spread by the wind to other leaves and other susceptible plants. Although this weather makes it hard to prevent, there are some things you can do to help: Be sure not to over crowd your plants – they need as much dry air and sun as possible. Do not water over the top of the plants late at night. Overhead water can possibly wash off some of the spores, but be careful because that can spread the spores to other leaves and plants. It also increases the humidity around the plant, and if done late at night the moisture has a chance to sit on the leaves for a longer period. The best practice is to always water in the early morning, water the soil area only and water over the top on the leaves a couple times a month to “clean” them off.
Killing the fungus once you have it can be done with Neem Oil. This is a great “green” product. It comes from a tree in Asia and it works well on pests and diseases. With its many uses it is a must have, especially in organic gardening. If you are unsure if you have mildew or if you have something else appearing on your plant please shoot us a picture at email@example.com.