Sourwood
oxydendrum arboreum
Also known as: ["Lily-of-the-valley tree","Seven-acre tree"]
Overview
A deciduous tree native to eastern North America, known for its drooping clusters of fragrant white flowers and brilliant fall foliage.
Benefits & Perks
["fragrant flowers","wildlife attractant (bees, butterflies, birds)","seasonal color change"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Ericales |
| Family: | Ericaceae |
| Genus: | Oxydendrum |
| Botanical Name: | Oxydendrum arboreum |
Plant Characteristics
Basic Information
- Category: Trees
- Suitable Location: acidic soil gardens, woodland edges, or as a specimen tree in a partially shaded landscape
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"–12–35°C"}
- Hardiness: {"zones":"5–9"}
- Misting: rarely required, but beneficial during dry periods
- Drainage: Well-draining to moist but not waterlogged.
- Soil Type: Acidic, well-draining, rich in organic matter (e.g., peat moss, compost).
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: moderate
- Pruning Frequency: Annually after flowering or as needed to remove dead/diseased branches.
- Pruning Intensity: Light to moderate, focusing on selective branch removal rather than heavy cutting.
Care Details
Ideal Sunlight Coverage:
Partial shade to full sun (4–6 hours of morning sun with afternoon shade preferred).
Sunlight Tolerance Tips:
Acclimate the plant gradually to full sun if moving from shade. Protect from intense afternoon sun to prevent leaf scorch. For indoor placement, provide bright, indirect light.
Care Requirements
Care Difficulty
moderatemoderate
Sunlight
partial shade to full sun, prefers morning sun and afternoon shade
Morning sun is ideal; avoid harsh afternoon sun; adjust light exposure gradually.
Watering
every 7–10 days, allowing soil to dry slightly between waterings
Water thoroughly until runoff, ensure good drainage, and avoid waterlogging the roots.
Soil
acidic, well-draining, organic-rich soil with high humus content
pH: Acidic (pH 4.5–6.0).
Use acidic soil mix; ensure good drainage; amend with peat or compost.
Temperature
Prefers cool to moderate temperatures (60–75°F or 15–24°C). Tolerates cold down to -20°F (-29°C) but thrives in cooler climates.
Protect from extreme heat; mulch in winter; maintain moderate temperatures for optimal growth.
Fertilizing
every 4–6 weeks during spring and summer with a balanced, slow-release fertilizer
Fertilize sparingly; use acid-loving plant food; apply in early spring.
Propagation
Methods
Softwood cuttings taken in early summer.
Step-by-Step Propagation Guide
- Take 4–6 inch cuttings.
- Remove lower leaves.
- Dip in rooting hormone.
- Plant in medium.
- Maintain humidity.
- Keep warm and bright.
Best Time: Early summer when new growth is semi-hardened.
Environment
High humidity (70–90%), warm temperatures (70–75°F or 21–24°C), and bright, indirect light.
Medium
Peat-based mix with perlite or sand for good drainage.
Hormone
Rooting hormone is recommended to improve success rates.
Timeline
Roots develop in 4–8 weeks; establish in pots or ground within 1–2 growing seasons.
Tools Needed
Pruning shears, rooting hormone, peat-based medium, plastic bags or propagator, misting bottle.
Quick Tips
Use softwood cuttings; maintain high humidity; keep warm and bright.
Pruning & Repotting
Pruning Guide
Method
Selective thinning of branches, heading back to shape, and removal of crossing or crowded stems.
Pruning Plan
Prune to maintain shape, remove dead or diseased wood, and encourage air circulation. Light pruning after flowering is ideal.
Tools
Pruning shears, loppers, gloves, disinfectant.
Checklist
Disinfect tools; prune after flowering; remove dead/diseased wood; shape lightly.
Repotting Guide
Best Season
Early spring before new growth begins.
Pot Size
One size larger pot (e.g., +2–3 inches in diameter).
Method
Gently remove the plant, trim any circling roots, place in a slightly larger pot with fresh, acidic soil mix, and water thoroughly.
Suggestions
Repot only when necessary, typically every 3–4 years or if the plant becomes root-bound.
Checklist
Choose appropriate pot size; use acidic soil mix; trim roots if needed; water well after repotting.
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 at the base of the plant, focusing on the root zone. Apply water slowly and deeply to encourage deep root growth, ensuring excess water drains away to prevent root rot. Water early in the morning to minimize evaporation and fungal issues.
Watering Schedule Tips
Water deeply once a week during the growing season, increasing frequency to twice weekly during hot, dry periods. Reduce watering in winter to once every 2–3 weeks, allowing soil to dry slightly between waterings.
Soil Improvement
Add peat moss, compost, or pine bark to increase acidity and organic content. Ensure good drainage by mixing in perlite or sand if needed.
Temperature Stress Management
Signs of Temperature Issues
Leaf scorch in excessive heat, leaf drop or browning in extreme cold, stunted growth in unsuitable temperatures.
Cold Stress
Low temperatures slow growth but do not typically harm the plant, which is hardy to USDA zone 4. Prolonged freezing without protection may cause root damage.
Solution: Mulch heavily around the base in winter to insulate roots. Protect from harsh winds and avoid overwatering when dormant.
Hot Stress
Excessive heat can cause leaf scorch, wilting, and reduced flowering. Stress may lead to leaf drop and poor growth.
Solution: Provide afternoon shade, increase watering during heatwaves, and use mulch to keep roots cool.
Fertilizing Guide
Fertilizing Checklist
Use balanced fertilizer; apply in spring; avoid over-fertilizing; water after application.
Fertilizing Method
Use a balanced, slow-release fertilizer in early spring. Apply a light dose of acid-loving plant food (e.g., rhododendron or azalea fertilizer) in late spring. Avoid over-fertilizing, as this plant is not heavy feeder.
Common Problems & Solutions
Toxicity Warning
Cats
Non-toxicOxydendrum arboreum is not known to be toxic to cats. There are no documented cases of adverse effects following ingestion or contact with this plant.
⚡ Toxic If:
if eaten
Dogs
Non-toxicOxydendrum arboreum is not known to be toxic to dogs. There are no documented cases of adverse effects following ingestion or contact with this plant.
⚡ Toxic If:
if eaten
Humans
Non-toxicOxydendrum arboreum, commonly known as sourwood, is generally considered non-toxic to humans. There are no known toxic effects or physiological impacts associated with its consumption or contact.
⚡ Toxic If:
if eaten
Frequently Asked Questions
Q: Does the Sourwood tree produce edible fruits?
A: No, the Sourwood tree does not produce edible fruits, though its nectar is used to make honey.
Q: What kind of soil does the Sourwood prefer?
A: The Sourwood prefers acidic, well-drained soil and partial shade to full sun.
Q: Is the Sourwood tree suitable for small gardens?
A: The Sourwood can grow up to 25–30 feet tall, so it is best suited for larger landscapes.
Quick Reference
| Family: | Ericaceae |
| Care: | moderate |
| Light: | partial shade to full sun, pre |
| Water: | every 7–10 days, allowing so |
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