Why Rhododendrons are Struggling and How to Help
What Happened to the Rhododendrons This Year?
If you noticed your rhododendrons aren’t looking their best, you’re not alone. There has been wide-spread damage of evergreens especially Rhododendron across the Northeast and has been an issue to address in all of our consults this Spring. Here are our thoughts and a path to recovery.
1. A Dry Summer and Fall
Rhododendrons, like all evergreens, rely on internal moisture to survive winter’s freezing temperatures. Last year’s drought left many plants entering winter already weakened and dehydrated. Without sufficient moisture in their stems, they were more vulnerable to freezing damage.
2. A Prolonged Winter
This winter, we experienced colder-than-usual temperatures that lasted longer than in recent years. In some gardens, the ground remained frozen into March. That deep freeze, followed by late snow and then rapid temperature swings with strong sun, created the perfect storm for:
Desiccation (drying out of leaves and stems) occurred because the ground was frozen and roots couldn’t absorb water.
Snow reflection intensified sunlight on exposed foliage, increasing the plants’ moisture needs—at a time when water wasn’t accessible.
The upper parts of the plant were especially vulnerable.
What Does the Damage Look Like?
Top leaves curled or browned, while bottom leaves may look fine
Toasted or crinkled stems at the tips
No sign of new growth yet on some branches.
This is classic winter burn and desiccation. Some stems may be dead, others may bounce back.
Could It Be Insects or Disease?
Unlikely, at least not in early spring. Insect pests like root weevils or borers become active later in the season (May–June). Diseases like phytophthora root rot typically cause decline during the growing season, not in March or April when nighttime temps are still chilly.
What You Can Do Now
We recommend a gentle, supportive approach—don’t prune yet! Here's your spring action plan:
Hydrate & Feed and Boost Soil Heath
Support root recovery with a soil drench using:
¼ cup Neptune’s Harvest + ¼ cup Espoma Bio-Tone Starter Plus in 5 gallons of water
Top-dress with compost to improve soil moisture retention and fertility.
Wait and Observe
Don’t cut back branches too soon. By late May or early June, you’ll begin to see where new growth is emerging. In some cases, buds along "dead-looking" stems can erupt as late as July.
Prune Carefully—Later
If stems are still lifeless by late June/early July, prune them back. Look for signs like crinkled, dry stems versus those that are still pliable and green inside.
For those interested in a deep dive on pruning, check out these articles from VA Tech and University of Maine Cooperative Extension (my favorite) on how, why and when to prune Rhododendrons: https://scholar.lib.vt.edu/ejournals/JARS/v34n3/v34n3-furniss.htm.
https://extension.umaine.edu/publications/2169e/
Prevention for the Future
Here’s how you can help your rhododendrons weather future winters:
Water deeply in Fall before the ground freezes.
Mulch well to regulate soil temperature and moisture. Always keep mulch 2” from the base of the plant.
Plants are resilient and many rhododendrons will bounce back. If your plant doesn’t recover, consider replacing it with a native or cold-hardy evergreen that can better tolerate the challenges of a Northeast winter.
Have questions about your rhododendrons, a native replacement or want help assessing your garden? Reach out—we’d love to help you create the garden of your dreams and breathe a little more life into your landscape.
With care, Lisa
