Sour rubber tree, Milk tree
couma guianensis
Also known as: ["Sour rubber tree","Milk tree","Curiate","Masticatory tree"]
Overview
A tropical tree native to South America, known for its milky latex and edible fruits.
Benefits & Perks
["edible fruits","wildlife attractant (bees, butterflies, birds)","shade tolerant"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Gentianales |
| Family: | Apocynaceae |
| Genus: | Couma |
| Botanical Name: | Couma guianensis |
Plant Characteristics
Basic Information
- Category: Trees
- Suitable Location: tropical garden or large indoor pot with bright, indirect light
- Suitable For:
- Is Weed: No
- Allergenicity: moderate
Environmental Needs
- Climate: {"temperatureRange":"20–35°C"}
- Hardiness: {"zones":"10–12"}
- Misting: every 2–3 days in dry environments
- Drainage: Fast-draining to prevent waterlogging.
- Soil Type: Well-draining potting mix with added organic matter like compost or peat.
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: moderate
- Pruning Frequency: Annually in late winter or early spring before new growth begins.
- Pruning Intensity: Moderate; remove up to one-third of the oldest stems to rejuvenate the plant.
Care Details
Ideal Sunlight Coverage:
Bright indirect light for 6–8 hours daily; can tolerate some direct morning sun but avoid harsh afternoon sun.
Sunlight Tolerance Tips:
Acclimate gradually to direct light; protect from intense midday sun; adjust placement based on indoor/outdoor conditions.
Care Requirements
Care Difficulty
moderatemoderate
Sunlight
partial shade to full sun
Rotate plant for even growth; use sheer curtains to filter intense light; avoid placing near hot windows.
Watering
every 7–10 days during growing season, reduce in winter
Water thoroughly until it drains from the bottom; allow soil to dry between waterings; avoid overwatering.
Soil
well-draining, fertile loam
pH: Slightly acidic to neutral (pH 5.5–7.0).
Use a mix with good drainage; avoid heavy clay soils; topdress with compost annually.
Temperature
Prefers 65–85°F (18–29°C); tolerates brief dips to 50°F (10°C) but thrives in warm, stable conditions.
Avoid sudden temperature changes; protect from drafts; maintain consistent warmth during active growth.
Fertilizing
every 4–6 weeks during active growth
Fertilize only when actively growing; flush soil occasionally to prevent salt buildup; avoid overfertilizing.
Propagation
Methods
Stem cuttings in spring or early summer.
Step-by-Step Propagation Guide
- Take a 4–6 inch cutting, remove lower leaves, apply rooting hormone, plant in medium, keep moist and humid.
Best Time: Spring or early summer when the plant is actively growing.
Environment
High humidity (70–80%), warm temperatures (75–85°F), and indirect light.
Medium
Well-draining mix of peat, perlite, and sand.
Hormone
Rooting hormone recommended for faster root development.
Timeline
Roots develop in 4–8 weeks; new growth appears in 2–3 months.
Tools Needed
Pruning shears, rooting hormone, small pots, plastic wrap or propagator.
Quick Tips
Use healthy, non-flowering stems; maintain consistent moisture; provide bottom heat for faster rooting.
Pruning & Repotting
Pruning Guide
Method
Selective thinning and heading back to promote airflow and compact growth.
Pruning Plan
Prune to maintain shape, encourage bushier growth, and remove dead or overgrown stems.
Tools
Clean, sharp pruning shears or scissors, disinfectant.
Checklist
Disinfect tools, prune during dormancy, remove dead/damaged growth, shape evenly.
Repotting Guide
Best Season
Spring, before the active growing season begins.
Pot Size
One size larger pot (e.g., +2 inches in diameter) with good drainage.
Method
Remove plant gently, trim roots if needed, place in a slightly larger pot with fresh soil, water lightly.
Suggestions
Repot every 2–3 years or when roots fill the pot; beneficial for growth and soil refresh.
Checklist
Check root bound status, prepare new pot, trim roots if necessary, use fresh soil, water sparingly post-repotting.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture, water deeply, ensure drainage, adjust for season.
How to Apply Water Properly
Water at the base of the plant, ensuring moisture reaches the root zone; water early in the morning to minimize evaporation; ensure excess water drains away to prevent waterlogging.
Watering Schedule Tips
Water deeply once the top inch of soil feels dry; reduce frequency in winter to prevent root rot.
Soil Improvement
Add perlite or coarse sand for drainage; incorporate organic matter for fertility; ensure proper aeration.
Temperature Stress Management
Signs of Temperature Issues
Yellowing leaves, leaf drop, stunted growth, or browning leaf edges.
Cold Stress
Slows growth, causes leaf discoloration, and may lead to root damage if temperatures drop below 50°F (10°C).
Solution: Move to a warmer location, insulate pots, avoid cold drafts, and reduce watering in cooler conditions.
Hot Stress
Wilting, leaf scorch, or leaf drop due to excessive heat and dryness.
Solution: Provide shade, increase humidity, water more frequently, and ensure good air circulation.
Fertilizing Guide
Fertilizing Checklist
Check growth phase, dilute fertilizer, apply to moist soil, avoid contact with leaves.
Fertilizing Method
Use balanced liquid fertilizer diluted to half strength every 4–6 weeks during spring and summer; reduce or stop in fall and winter.
Common Problems & Solutions
Toxicity Warning
Cats
Non-toxicCouma guianensis is not considered toxic to cats. The plant lacks compounds that are known to be harmful to felines.
⚡ Toxic If:
Generally non-toxic
Dogs
Non-toxicCouma guianensis is not known to be toxic to dogs. The plant does not produce any known compounds that are harmful to canines.
⚡ Toxic If:
Generally non-toxic
Humans
Non-toxicCouma guianensis, commonly known as the 'sweetwood' or 'milkwood', is not considered toxic to humans under normal circumstances. The plant is often used for its sweet sap, which is edible and has been traditionally consumed by indigenous populations.
⚡ Toxic If:
Generally non-toxic
Frequently Asked Questions
Q: Is Couma guianensis toxic to pets?
A: It is mildly toxic to dogs and cats if ingested.
Q: What are the uses of Couma guianensis?
A: The latex is used traditionally for chewing, and the fruits are edible.
Q: How difficult is it to care for Couma guianensis?
A: It requires moderate care, including proper watering and sunlight.
Quick Reference
| Family: | Apocynaceae |
| Care: | moderate |
| Light: | partial shade to full sun |
| Water: | every 7–10 days during growi |
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