English Ivy (Hedera varieties) is a tough plant that is hard to kill, however overwatering is one way that you can do it. According to horticulturist Ron Smith, "English ivies do not need a lot of water, so when you think they need water, think again and water at least a day later."
Some outward signs of over watering include wilting, yellow leaves, dropping of lower leaves and stunted growth. Unfortunately, these are also signs of under watering and can be caused by other factors. If you notice these symptoms, there is a larger problem going on, but it may not always be over watering.
Over watering means that the soil of the plant was wet for an extended period of time. Over watering is not caused giving the plant too much water at once, but by watering it too frequently. When it is watered too frequently, the soil is not allowed to dry out properly between them, which means allowing the top 1/3 of the soil to dry out before watering.
Edema is a condition that is caused when there is too much water in the foliage. Tiny blisters develop on the undersides of the lower leaves. These blisters may callus over and appear as tan or rust-brown warts.
Over watering can make an English Ivy susceptible to Phytophthora mold species which include palmivora, cinnamom and nicotiana. These molds can cause root rot, stem blight and leaf spot. Symptoms include lower leaves turning brown and curling, poor top growth and poor color.
Bacterial Leaf Spot and Leaf Blight
In addition to giving bacteria a place to grow, over watering stresses the plant, making it more susceptible to bacterial diseases including leaf spot and leaf blight. Symptoms include leaf spots, wilting, tip burns or lesions on the leaves.