The willow tree's sweeping canopy makes a dramatic focal point in a landscape. But willows have a history of being susceptible to fungal disease, pests and winter damage. It is imperative when planting a willow to think of its growing requirements to prevent future problems. These trees like moist soil, full sunlight and lots of room. Prompt care must be given to a willow if you notice any leaf discoloration, stunted growth or defoliation.
Pour 70 percent denatured alcohol and 30 percent water into a spray bottle. Sterilize your pruning saw by spraying the saw with the mixture and drying with a towel. Sterilize your pruning tool in between cuts.
Dig next to any suckers growing from the root ball of your willow tree. Make a flush cut to remove the sucker from the root ball. Suckers or water sprouts are branches that grow from willow tree root balls when the tree is distressed. These branches steal important nutrients meant for the rest of the tree.
Remove any branches that have become infected with a fungal disease by cutting them off near the branch collar. Willow trees can become infected with crown gall, willow scab and black cankers. Look for spots on leaves, green spores underneath leaves, lesions on twigs or branches and dieback.
Scrape the top of a branch to see if it is dead from damage or disease. If you see greenish white underneath the scrape, the branch is alive. Brown or black under the scrape indicate the branch is dead and should be removed.
Apply a fertilizer underneath the canopy of the tree and extending 1 foot past its dripline. The dripline is the area underneath the outer branches. Use an all purpose fertilizer with a nitrogen-phosphorous-potassium (NPK) ratio of 10-10-10 and distribute it on the soil according to the directions. Water the tree thoroughly.