Silver Dollar Gum, Red Box
eucalyptus polyanthemos
Also known as: ["Silver Dollar Gum","Red Box"]
Overview
A medium-sized evergreen tree native to Australia, known for its distinctive silver-grey juvenile leaves and rough, fibrous bark.
Benefits & Perks
["drought tolerant","wildlife attractant (bees, butterflies, birds)","aesthetic foliage"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Myrtales |
| Family: | Myrtaceae |
| Genus: | Eucalyptus |
| Botanical Name: | Eucalyptus polyanthemos |
Plant Characteristics
Basic Information
- Category: Trees
- Suitable Location: outdoor garden in open, sunny areas with good air circulation
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"–12–35°C"}
- Hardiness: {"zones":"7–10"}
- Misting: rarely required, only if ambient humidity is very low
- Drainage: Fast-draining to prevent root rot.
- Soil Type: Well-draining, slightly acidic to neutral soil mix. A combination of potting soil, sand, and perlite works well.
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: high
- Pruning Frequency: Annually in late winter or early spring before new growth begins. Light pruning can be done as needed year-round.
- Pruning Intensity: Moderate. Remove up to one-third of the oldest stems to rejuvenate growth.
Care Details
Ideal Sunlight Coverage:
Full sun (6–8 hours of direct sunlight daily). Tolerates partial shade but may become leggy or less vigorous.
Sunlight Tolerance Tips:
Acclimate plants gradually to intense sunlight if moved from shade. Protect from harsh midday sun in hot climates to prevent leaf scorch. Indoors, place near a south-facing window for optimal light.
Care Requirements
Care Difficulty
moderatemoderate
Sunlight
full sun
Rotate plant weekly for even growth; use sheer curtains to filter intense summer sun; avoid sudden light changes.
Watering
every 7–10 days, allowing soil to dry between waterings
Water thoroughly until runoff occurs; allow soil to dry partially between waterings; avoid frequent shallow watering.
Soil
well-drained, sandy loam with moderate fertility
pH: 6.0–7.0 (slightly acidic to neutral).
Use a mix with good aeration; avoid heavy clay soils; ensure pots drain freely; top-dress with compost annually.
Temperature
Prefers warm temperatures (65–85°F or 18–29°C). Tolerates mild frosts but thrives in temperate to subtropical conditions.
Avoid placing near drafty windows or heat vents; protect from sudden temperature swings; adjust watering in extreme heat.
Fertilizing
every 2–3 months during active growth with a balanced, slow-release fertilizer
Fertilize sparingly to avoid salt buildup; apply before watering to prevent root burn; stop fertilizing in fall to prepare for dormancy.
Propagation
Methods
Stem cuttings or seed. Stem cuttings are more reliable for home growers.
Step-by-Step Propagation Guide
- Take 4–6 inch cuttings.
- Remove lower leaves.
- Dip in rooting hormone.
- Plant in medium.
- Maintain humidity.
- Water lightly.
Best Time: Spring or early summer when the plant is actively growing.
Environment
Warm (70–75°F or 21–24°C), humid, and bright but indirect light. Protect from direct sun and drafts.
Medium
Well-draining mix of perlite and peat moss or cactus potting mix.
Hormone
Recommended to use rooting hormone for faster and more reliable rooting.
Timeline
Roots typically form in 4–8 weeks; establishment may take 3–6 months.
Tools Needed
Pruning shears, rooting hormone, small pots, misting spray bottle, plastic wrap or propagator.
Quick Tips
Use healthy, non-flowering stems; keep soil consistently moist but not waterlogged; provide bottom heat if possible.
Pruning & Repotting
Pruning Guide
Method
Use clean, sharp tools. Cut just above a leaf node or lateral branch. Remove crossing or crowded branches to improve structure.
Pruning Plan
Prune to maintain shape, encourage bushiness, and remove dead or diseased wood. Pruning also improves air circulation and light penetration.
Tools
Pruning shears, loppers (for larger branches), sterilizing solution (e.g., rubbing alcohol).
Checklist
Sterilize tools; prune before flowering; remove dead/diseased wood; shape the plant; clean up debris.
Repotting Guide
Best Season
Early spring before the growing season begins.
Pot Size
Increase pot size by 2–3 inches in diameter. Ensure the new pot has drainage holes.
Method
Remove the plant gently; trim any circling roots; place in a slightly larger pot with fresh, well-draining soil; water thoroughly after repotting.
Suggestions
Repot every 2–3 years or when roots fill the pot. Eucalyptus polyanthemos can become large, so consider its final size when choosing a container.
Checklist
Choose appropriate pot size; prepare fresh soil mix; trim roots if necessary; water after repotting; place in shade for a few days.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture before watering; water deeply; ensure drainage; adjust frequency seasonally.
How to Apply Water Properly
Water directly at the root zone, ensuring even saturation of the soil. Apply water slowly to allow absorption and prevent runoff. Ensure excess water drains freely from the pot or soil surface. Water early in the morning to minimize evaporation and fungal growth.
Watering Schedule Tips
Water deeply once every 7–10 days during active growth in spring and summer; reduce frequency to every 2–3 weeks in fall and winter. Adjust based on rainfall and soil moisture retention.
Soil Improvement
Add perlite or coarse sand to improve drainage. Incorporate compost for organic matter and fertility. Ensure pots have adequate drainage holes.
Temperature Stress Management
Signs of Temperature Issues
Chlorosis or leaf drop in cold stress; wilting or scorched leaves in excessive heat.
Cold Stress
Low temperatures slow growth and may cause leaf drop or dieback. Prolonged cold can damage roots and lead to fungal infections.
Solution: Protect from frost with frost cloth or mulch. Move potted plants indoors during freezes. Ensure good air circulation to prevent fungal issues.
Hot Stress
Excessive heat can cause leaf scorch, wilting, or premature leaf drop. Stress may reduce flowering and vigor.
Solution: Provide afternoon shade in extreme heat. Water deeply to cool roots. Use mulch to retain soil moisture and regulate temperature.
Fertilizing Guide
Fertilizing Checklist
Use balanced fertilizer; apply in spring; dilute liquid fertilizers; avoid winter feeding.
Fertilizing Method
Use a balanced, slow-release fertilizer (e.g., 10-10-10) in spring before active growth. Apply a diluted liquid fertilizer monthly during growing season; avoid fertilizing in winter.
Common Problems & Solutions
Toxicity Warning
Cats
Slightly ToxicCats are particularly sensitive to essential oils, and ingestion of Eucalyptus polyanthemos can cause mild to moderate gastrointestinal upset. The plant should be kept out of reach to prevent accidental consumption.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Dogs
Slightly ToxicIn dogs, ingestion of Eucalyptus polyanthemos can lead to mild gastrointestinal distress due to the presence of essential oils. Symptoms are typically mild but can be more pronounced in smaller or sensitive breeds.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Humans
Slightly ToxicEucalyptus polyanthemos contains essential oils that can cause mild gastrointestinal upset and skin irritation upon ingestion. The physiological impact is generally limited to mild discomfort, though larger quantities may exacerbate symptoms.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Frequently Asked Questions
Q: Is Eucalyptus polyanthemos suitable for small gardens?
A: No, it is a medium-sized tree and requires ample space to grow.
Q: Does this plant attract wildlife?
A: Yes, it is known to attract bees, butterflies, and birds.
Q: How drought-tolerant is this species?
A: It is highly drought-tolerant once established.
Quick Reference
| Family: | Myrtaceae |
| Care: | moderate |
| Light: | full sun |
| Water: | every 7–10 days, allowing so |
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