In the spring my wisteria has lots of new green growth but then it dies back and gets very thin. I keep it watered but it still looks sick. I have one out in the front yard and never do anything to it and it is gorgeous. Can it be because it is planted close to the house?
The Gardener’s Answer
Hello, Cindy in Texas: Wisteria require full sun, so if the vine closer to the house is not getting a minimum of six hours of direct sunlight each day this could be the problem. Otherwise, they prefer a slightly acidic soil pH of 6.0-7.0 and a moist but well-drained soil. Is the vine by the house receiving more moisture than the other? If so, you should cut back on your watering. Established vines should not need to be watered unless Mother Nature does not provide moisture for an extended period of time. Over-watering can cause rot issues and plant defoliation. There are not many insect or disease problems that affect these vines, but if the foliage does not look healthy you should take a sample to your County Extension Office for the horticulture agent to make a diagnosis. Wisteria are really tough plants and opposite of what we typically think of in terms of keeping these vines happy. If the problem was lack of blooms, they tend to bloom when they are stressed, so severe pruning can encourage to them to bloom. Too much fertilizer is a bad thing for these vines, especially fertilizer high in nitrogen, because it encourages leafy growth instead of blooms. If you are fertilizing, you may need to cut back and let the vine use up what already exists in the soil. If you are giving the wisteria by the house a lot more attention than the other, you have answered your own question: they like to be ignored!