Overwintering Hibiscus Indoors: Powdery Mildew & Pruning

Hibiscus plants brought indoors for winter often develop powdery mildew — a white, granular coating on leaves — due to cooler temperatures, reduced light, and lower humidity. This fungal issue is manageable and doesn't warrant discarding your plants.

Treating Powdery Mildew

Spray the entire plant (including leaf undersides) with a Lysol-type disinfectant spray every 3-4 days for 5 treatments. Hold the can 12 inches away. This disrupts the fungal lifecycle. Monitor for recurrence as spring approaches and conditions improve.

Essential Winter Care

• Pruning: Cut all branches back by half, just above a leaf node, to encourage bushier growth and more blooms
• Light: Sunroom is ideal; maximize exposure
• Water: Reduce frequency; allow soil to dry more between waterings
• Fertilizer: Use bloom-boosting formula (high middle number) monthly
• Temperature: Nights in low 50s°F are acceptable but not ideal

Benefits Beyond Blooms

Your hibiscus actively purifies indoor air by absorbing pollutants and releasing oxygen — a valuable winter benefit. The messy leaf drop and mildew are temporary; proper pruning and spring transition will restore vigor.

Spring Transition

Gradually acclimate to outdoors after frost danger passes. Expect some winter growth to sunburn — this is normal. Resume regular fertilizing and watering for a spectacular summer display.