Limelight hydrangeas are a cultivar with a longer blooming season than most hydrangea plants. Limelights differ from bigleaf and oakleaf hydrangeas in that they have smaller leaves and larger blossoms. The blossoms start out as a white-chartreuse and change to a lime-green throughout the bloom season. The shrub is hardy from zones 3 through 9 and grows up to 8 feet tall. Pruning should be done with an eye toward the size of blossom and shrub that you want.
Time pruning for late fall or early spring. Limelight hydrangeas grow on new growth, and should be pruned between growing seasons.
Determine whether you want smaller, more numerous blooms or larger, fewer blooms. The more you prune, the fewer blooms you will have. But the larger these blooms will be.
Sharpen your pruning shears before you prune a Limelight hydrangea. This will prevent injury to the plant and help it to recover faster.
Mix a solution of nine parts bleach and one part water. Saturate a cloth with this solution and wipe the blades of your shears with the solution between pruning Limelight hydrangeas to prevent the spread of disease.
Remove any dead, diseased or broken stems.
Remove 1/3 of the oldest plant stems at ground level once the plant turns 4 years old.
Cut back the top 1/3 to 1/2 of the remaining stems just above a healthy bud. This process is called heading back.