African Milk Tree with Boron Deficiency? Rare but Treatable
Euphorbia trigona
Boron deficiency is a nutrient disorder that affects plant growth and development, particularly at growing points. Boron is essential for cell wall formation, reproductive development, and carbohydrate transport. While critical for plant health, boron has a narrow range between deficiency and toxicity, requiring careful management.
ð Symptoms
- âĒ Dying or brown growing tips and terminal buds
- âĒ Stunted, bushy growth with shortened stem segments
- âĒ Young leaves become thick, brittle, wrinkled or distorted
- âĒ Yellowing (chlorosis) of young foliage
- âĒ Brown necrotic spots on leaf tips and margins
- âĒ Poor root development with stubby, thickened roots
- âĒ Flower abortion and poor fruit set
- âĒ Hollow stems or internal browning in severe cases
â Possible Causes
- â Low boron levels in soil or growing medium
- â High pH conditions (above 6.5) that reduce boron availability
- â Sandy or heavily leached soils with low organic matter
- â Drought or low soil moisture preventing boron uptake
- â Excessive calcium or potassium interfering with boron absorption
- â Cold soil temperatures limiting nutrient uptake
ð Treatment
Quick Fixes
Identify symptoms quickly
Confirm dying growing tips, stunted bushy growth, and brittle leaves indicate boron deficiency.
Check soil pH
Use pH meter or test strips. If pH is above 6.5, boron is locked up.
Prepare foliar spray
Mix 1/4 teaspoon of borax per gallon of water. Add a drop of dish soap as surfactant.
Apply foliar spray
Spray leaf surfaces (especially undersides) early morning or evening. Foliar application provides fast uptake.
Soil drench application
Mix 1 teaspoon borax per gallon water and drench root zone. Use 1 cup per plant for containers, more for garden beds.
Flush with water
After 2-3 days, water plants thoroughly to distribute boron and prevent localized toxicity.
Monitor response
Watch new growth over 1-2 weeks. If improvement stalls, consider pH adjustment or reapplication.
Organic Treatment
Confirm deficiency
Examine symptoms carefully: dying growing tips, thick brittle leaves, and poor flowering indicate boron deficiency.
Test pH levels
Check soil or growing medium pH. If above 6.5, boron is likely locked up and unavailable.
Adjust pH naturally
If pH is high, apply sulfur or organic acidifiers to bring pH down to 5.5-6.5 range.
Apply compost
Work 2-3 inches of well-aged compost into soil or top-dress container plants. Compost provides slow-release boron.
Apply kelp or seaweed
Water with liquid kelp or seaweed extract (follow label rates). These are naturally rich in boron and other trace minerals.
Prepare borax solution
Dissolve 1 teaspoon of household borax in 1 gallon of water. This creates a safe, dilute boron solution.
Apply borax carefully
Water plants with borax solution once, using about 1 cup per square foot. Do NOT over-apply as boron toxicity is easy to cause.
Ensure proper watering
Keep soil consistently moist (not waterlogged). Boron uptake requires adequate moisture.
Monitor new growth
Watch for healthier new leaves and growing tips over the next 2-4 weeks. Recovery is gradual.
ðĄïļ Prevention
- â Maintain soil pH between 5.0-6.5 for optimal boron availability
- â Incorporate organic matter (compost) to improve boron retention
- â Ensure consistent moisture levels; avoid prolonged drought
- â Test soil regularly and apply boron only when needed
- â Avoid over-liming which raises pH and locks up boron
- â Use balanced fertilizers that include micronutrients
ðą Care Guide: African Milk Tree
ð§ How to Water
Water only when soil is completely dry, typically every 3-4 weeks. Reduce watering in winter. Wrinkled leaves indicate thirst. Yellowing or browning may signal overwatering and root rot.
âïļ Lighting
Prefers bright indirect light to direct sunlight. Can tolerate some direct morning or afternoon sun. Avoid harsh midday sun which may cause scorching. Also adapts to medium light conditions.
ðŠī Ideal Soil
Use well-draining sandy or cactus mix. A 2:1:1 blend of cactus soil, perlite, and coarse sand works well. Good drainage is essential to prevent root rot.