Limelight is the most useful of the panicle hydrangeas for cutting — massive cone-shaped flower heads emerge pale green in summer, turn creamy white, then age through pink and dusty rose to parchment-bronze in autumn. A single mature shrub can produce dozens of stems per season. Flowers at every stage are beautiful and useful in arrangements.
Cut for fresh use when the flowers are fully expanded but still firm — late-summer stems at the white stage last the longest in water. For dried use, cut in early autumn when they are beginning to age to pink; hang upside-down in a warm, airy place or simply stand them in an empty vase. Prune hard in late winter or early spring — flowers form on new wood.
Powdery mildew
White or grey powdery coating on leaves — usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.