Why Are My Nandina Leaves Turning Brown

If you’re noticing unsightly brown leaves on your nandina, you’re likely wondering what’s gone wrong. This article will explain why are my nandina leaves turning brown and how to fix the problem.

Nandina, or heavenly bamboo, is generally a tough plant. But browning leaves are a common sign of stress. The causes range from simple environmental issues to more serious diseases. Let’s look at the most likely reasons so you can get your shrub back to health.

Browning can appear in different ways. It might be leaf tips, whole leaves, or sections of the plant. Where and how the browning shows up is your first clue. Here are the primary culprits.

Environmental Stress and Water Issues

This is the most frequent cause of browning. Nandina prefers consistent conditions, and sudden changes can shock it.

Underwatering or Drought Stress: Nandina needs regular water while establishing. Extended dry periods, especially in full sun, cause leaves to scorch, turning them brown and crispy from the edges inward. Older leaves often show damage first.
Overwatering and Poor Drainage: This is just as harmful. Soggy soil suffocates roots, leading to root rot. The plant can’t take up water or nutrients, so leaves turn brown, often starting with a wilted, yellowing look before browning. Check if the soil is constantly wet.
Winter Burn or Cold Damage: In colder zones, winter winds and frost can desiccate leaves, causing browning or blackening. This is especially common on young plants or in exposed, windy sites.
Fertilizer Burn: Applying too much fertilizer, or placing it too close to the stems, can burn the roots. This damage shows up as brown leaf margins and tips.

Pests and Diseases

While nandina is relatively pest-resistant, a few problems can cause browning.

Root Rot (Phytophthora or Pythium): Caused by fungal pathogens in waterlogged soil. Leaves turn yellow, then brown, and the plant may appear stunted. The base of the stems might feel soft.
Bacterial Leaf Scorch: This disease causes leaves to turn brown from the margins inward, often with a yellow halo separating the brown from the green. It can spread through the plant over time.
Spider Mites: These tiny pests suck sap from leaves, causing stippling (tiny yellow dots) that can merge into overall browning and dryness. Look for fine webbing on the undersides of leaves.

Cultural and Site Problems

Sometimes, the issue is where or how the plant is growing.

Too Much Sun (Leaf Scorch): While nandina tolerates sun, intense, reflected heat from walls or pavement in very hot climates can scorch leaves, causing browning.
Transplant Shock: Recently planted nandinas may drop or brown leaves as they adjust to their new location. This is usually temporary if care is good.
Natural Aging: Don’t panic! It’s normal for individual older leaves at the bottom or inside the shrub to turn red or brown and fall off as part of the plant’s natural cycle.

How to Diagnose the Problem

Follow these steps to pinpoint the cause of your nandina’s brown leaves.

Check the Pattern: Is browning at the tips, on outer leaves, or inner ones? Is it on one side or the whole plant? Whole-plant browning suggests a root or water issue. Scattered browning might be pests or disease.
Feel the Soil: Dig down a few inches. Is it bone dry or swampy? Proper soil should be moist but not wet.
Examine the Leaves: Look closely at both sides of brown leaves, especially underneath. Use a magnifying glass to check for tiny pests or webbing.
Consider Recent Changes: Did you just plant it, fertilize it, or has there been a extreme weather event like a heatwave or hard freeze?
Inspect the Stems and Roots: For severe cases, gently check the base of the stems and some roots. Soft, mushy, or black roots indicate rot.

Solutions and Treatment for Brown Nandina Leaves

Once you’ve identified the likely cause, take action with these targeted solutions.

Fixing Watering Problems

For Underwatering: Deeply water the plant, allowing moisture to reach the root zone. Apply a 2-3 inch layer of mulch around the base (not touching the stems) to retain soil moisture. Water regularly during dry spells.
For Overwatering/ Root Rot: Stop watering immediately. Let the soil dry out. If the plant is in poorly draining soil, you may need to improve drainage around it or, as a last resort, replant it in a raised bed or better-drained location. For confirmed root rot, a fungicide labeled for Phytophthora may help in early stages, but severe cases are hard to fix.

Addressing Environmental Stress

For Winter Burn: Prune out dead, brown growth in spring after new growth begins. Protect young plants with burlap screens in winter to shield them from wind.
For Fertilizer Burn: Leach the soil by applying slow, deep watering for an extended period to help flush excess salts from the root zone. Avoid fertilizing again until the plant recovers.
For Leaf Scorch from Sun: Provide afternoon shade if possible, or ensure the plant is receiving adequate water to cope with the heat. Temporary shade cloth can help a stressed plant.

Managing Pests and Disease

For Spider Mites: Spray the foliage forcefully with a strong jet of water to dislodge mites. For heavier infestations, use insecticidal soap or horticultural oil, making sure to coat the undersides of leaves.
For Bacterial Leaf Scorch: There is no cure. Prune out affected branches to improve appearance and slow spread. Focus on keeping the plant healthy with proper water and nutrition to help it cope. Avoid overhead watering.
For Fungal Issues: Remove and discard severely affected leaves. Improve air circulation by thinning out dense growth. Apply a fungicide as a preventative if fungal problems are common in your area.

Pruning and Ongoing Care

Pruning is often necessary to remove brown, damaged growth and encourage healthy new leaves.

Timing: The best time for major pruning is late winter or early spring before new growth starts. You can remove unsightly brown leaves anytime.
Method: Use clean, sharp pruners. For overall rejuvenation, you can cut the entire plant back to about 6-12 inches from the ground. It will regrow. For selective pruning, cut stems back to a healthy leaf node or to the base of the plant.
Prevention: Plant nandina in well-draining soil. Water deeply but infrequently, allowing the top inch of soil to dry between waterings. Apply a balanced, slow-release fertilizer in spring if needed, but avoid overfeeding. Choose a site with appropriate sun for your climate.

FAQ About Nandina Problems

Q: Should I cut the brown leaves off my nandina?
A: Yes, you can prune off brown leaves and stems for cosmetic reasons and to help prevent any potential disease spread. It also encourages the plant to put energy into new growth.

Q: Can a nandina with completely brown leaves recover?
A: It depends on the cause. If the stems are still green and pliable, and the roots are healthy, the plant can often recover with corrected care and spring pruning. If the stems are brittle and the roots are rotted, recovery is less likely.

Q: Is it normal for nandina leaves to turn brown in winter?
A: Some browning or purpling in cold weather is normal, especially for certain varieties. Severe browning and dieback, however, usually indicates winter burn from harsh conditions.

Q: How often should I water my nandina?
A: There’s no set schedule. Water newly planted nandina regularly for the first season. Established plants are drought-tolerant but benefit from a deep soaking during prolonged dry periods. Always check soil moisture first.

Q: Why are only the tips of my nandina leaves turning brown?
A: Brown tips are classic signs of underwatering, low humidity, or possibly fertilizer burn. Check your watering habits and ensure you’re not over-fertilizing.

By understanding these common causes, you can quickly diagnose your plant. Most often, adjusting your watering practices is the key. With a little targeted care, your nandina can bounce back, producing it’s beautiful foliage and berries once again.