Why Emerald Green Arborvitae Turn Brown: Sun, Water, and Competition

Diagnosing the Problem

Your 5-foot Emerald Green arborvitae are browning heavily—inside, on one side, and even at the store, though less severely. Three factors likely combine:

1. Insufficient Sunlight

Arborvitae require full sun. Only 1.5 hours of daily sun is far below their needs, causing thin, brown interior growth.

2. Watering Issues

Newly planted arborvitae need consistent, deep watering. Half-flow watering for 15–20 minutes may not penetrate the root ball, especially in summer heat. Water deeply every 2–3 days until established.

3. Root Competition

Overhanging trees compete for water and nutrients. Their shade also reduces light further.

Remedial Actions

• Prune overhanging branches now (dormant season) to increase light.
• Water deeply with a soaker hose, then apply 3 inches of mulch.
• Monitor for recovery—if browning continues into spring, replacement may be necessary.