Why Hydrangea Leaves Turn Brown

 

Brown hydrangea leaves happen when something isn't quite right with their environment or how they’re being cared for. The most common reasons for brown leaves on hydrangeas are not enough water, too much direct sunlight, harsh weather, unhealthy soil, pests, or diseases. Each cause leads the leaves to dry out, get damaged, or become sick, showing up as brown spots, edges, or full brown leaves.

 

Common Causes and How to Spot Them

 

• Not Enough Water (Drought Stress): Hydrangeas have big, soft leaves that dry out easily if they don’t get enough water. If the soil feels dry and the leaves are crispy or turning brown mostly at the edges or tips, underwatering is likely the problem.
• Too Much Sun (Sun Scorch): Most hydrangeas prefer morning sun and afternoon shade. If your plant gets strong, direct sunlight for many hours, especially during hot days, leaves will turn brown—often just on the sides exposed to the sun. You might also see leaves curling or looking faded before they brown.
• Poor Water Drainage or Overwatering: While hydrangeas need moisture, too much water or soggy soil can also lead to browning. Roots can suffocate and rot, causing leaves to discolor (sometimes yellow first, then brown) and drop off. Check if water pools around your plant or the soil feels overly wet.
• Wind or Frost Damage: Strong winds suck moisture from leaves, especially in exposed spots. Cold or frost can also burn the leaves, leading to brown, papery patches even overnight in spring or fall.
• Poor Soil and Nutrient Issues: Hydrangeas like rich, well-draining soil. If the soil is too sandy, clay-heavy, or lacking nutrients (like iron or magnesium), leaves may turn brown, pale, or have odd coloring between the veins (this is called chlorosis).
• Pests: Bugs like spider mites, aphids, or beetles can attack hydrangeas, sucking the sap or chewing on them. This rarely turns the whole leaf brown, but you might see brown spots or ragged, eaten edges. Look for tiny bugs, webs, or sticky residue on leaves.
• Disease: Fungal or bacterial infections cause brown spots, rings, or full leaf browning. Common problems include leaf spot diseases, powdery mildew, or botrytis. These show as uneven patches, sometimes with yellow halos, and may spread quickly in wet weather.
• Chemical Burns: Accidentally getting fertilizer, weed killer, or other garden chemicals on the leaves can cause sudden browning, often in the spots where chemicals touched the plant.

 

How to Tell Which Problem is Affecting Your Plant

 

• Check the Soil: Stick your finger two inches into the soil. If it's dry, underwatering is the likely cause. If it's muddy or has a rotten smell, it's likely overwatering or poor drainage.
• Watch the Sun Pattern: See how much direct sunlight your hydrangea gets, especially from noon to 4pm. Leaves exposed to midday or afternoon sun are most likely to burn.
• Look Closely at the Leaves: Brown edges and tips are usually drying (water or wind). Large, spreading brown spots may be a disease. Small dots or webbing may point to pests.
• Inspect for Bugs and Spots: Turn leaves over, look for insects, sticky material, or obvious signs of chewing. Check for black, gray, white, or yellow spots that aren’t just brown—these could be disease or pests.
• Notice the Environment: Remember if you recently fertilized, sprayed, or had strange weather (frost or heat wave). Chemical or weather burns can turn leaves brown suddenly.

 

How to Fix Brown Leaves and Keep Your Hydrangea Healthy

 

• Water Deeply, Not Too Often: Water your hydrangea deeply once or twice a week, enough to keep the soil evenly moist. Try to water early in the day. Reduce watering if soil is constantly wet.
• Give Shade at the Hottest Part of Day: If possible, plant or move your hydrangea where it gets morning sun and afternoon shade. For existing plants, create temporary shade with fabric or an umbrella in mid-summer.
• Improve Drainage: If your soil stays soggy, mix in compost or sand, or move your plant to a raised bed or pot with holes on the bottom.
• Mulch: Spread a 2–3 inch layer of mulch (like wood chips or bark) around the base of your plant. This holds in moisture and shields roots from heat.
• Protect from Strong Winds: Plant near a wall, fence, or larger shrubs that can block wind, especially in exposed gardens.
• Fertilize Carefully: Feed with a balanced, slow-release fertilizer meant for flowering shrubs in spring. Don’t overdo—it’s easy to burn roots.
• Remove Damaged Leaves: Prune off brown or sick leaves to stop disease spread and help the plant use energy for healthy growth.
• Treat Pests or Disease: For bugs, wash leaves with soapy water or use insecticidal soap. For fungal diseases, apply a garden fungicide or remove affected leaves and dispose of them far from the plant.
• Avoid Leaf Wetting: Water at the soil level, not on the leaves, to help prevent fungal problems.

 

When to Worry and When Not To

 

Some browning on old, lower leaves is natural as the plant grows. But if you see lots of brown, it spreads quickly, or whole branches are dying, act quickly using the tips above. Keep the area around your hydrangea tidy and make small changes one at a time. With some care, most hydrangeas bounce back easily.