Pacific Ninebark
physocarpus capitatus
Also known as: ["Western Ninebark","Cascades Ninebark"]
Overview
A deciduous shrub native to western North America, known for its exfoliating bark and clusters of small, creamy-white flowers.
Benefits & Perks
["disease resistant","wildlife attractant (bees, butterflies, birds)","shade tolerant"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Rosales |
| Family: | Rosaceae |
| Genus: | Physocarpus |
| Botanical Name: | Physocarpus capitatus |
Plant Characteristics
Basic Information
- Category: Shrubs
- Suitable Location: border plantings or naturalized areas
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"–34.4–38°C"}
- Hardiness: {"zones":"3–7"}
- Misting: rarely required
- Drainage: Moderate to fast-draining; avoid waterlogged conditions.
- Soil Type: Well-draining, loamy soil with organic matter; tolerates sandy or clay soils if amended.
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: moderate
- Pruning Frequency: Annually after flowering; light pruning can be done as needed throughout the growing season.
- Pruning Intensity: Moderate; remove up to one-third of old growth to rejuvenate the plant.
Care Details
Ideal Sunlight Coverage:
Full sun to partial shade (4–6 hours of direct sunlight daily); tolerates light shade, especially in hot climates.
Sunlight Tolerance Tips:
Acclimate plants gradually to full sun if moved from shade; protect from intense midday sun in hot regions; adjust placement based on seasonal light intensity.
Care Requirements
Care Difficulty
easymoderate
Sunlight
full sun to partial shade
Morning sun is ideal; provide afternoon shade in hot areas; rotate pots for even growth.
Watering
every 7–10 days during active growth, less frequently in winter
Water thoroughly but infrequently to encourage deep roots; ensure soil dries slightly between waterings; prioritize morning watering to reduce evaporation.
Soil
well-drained, loamy soil
pH: Slightly acidic to neutral (pH 6.0–7.0).
Ensure good drainage; amend heavy clay with organic matter; test pH periodically.
Temperature
Hardy in USDA zones 3–7; tolerates cold winters down to -30°F (-34°C); prefers moderate summer temperatures (60–75°F / 15–24°C).
Protect from late spring frosts; water deeply before freezes; provide shade during heatwaves.
Fertilizing
every 2–3 months during spring and summer
Fertilize only in spring; use half-strength liquid fertilizer if needed; avoid over-fertilizing to prevent root burn.
Propagation
Methods
Softwood cuttings in late spring or early summer; division of root clumps in early spring.
Step-by-Step Propagation Guide
- Take 4–6 inch cuttings.
- Remove lower leaves.
- Dip in rooting hormone.
- Plant in medium.
- Maintain humidity.
- Transplant when rooted.
Best Time: Late spring to early summer for cuttings; early spring for division.
Environment
Warm, humid environment (70–75°F / 21–24°C); indirect light; consistent moisture.
Medium
Well-draining potting mix with perlite or sand; can root in water initially.
Hormone
Rooting hormone recommended for faster and more reliable rooting.
Timeline
Cuttings root in 4–8 weeks; division establishes in 1–2 growing seasons.
Tools Needed
Pruning shears, rooting hormone, small pots, misting spray bottle, plastic bags (for humidity).
Quick Tips
Take cuttings in the morning; keep soil consistently moist; provide bottom heat for faster rooting.
Pruning & Repotting
Pruning Guide
Method
Selective thinning of branches; heading back to encourage denser growth; remove crossing or damaged stems.
Pruning Plan
Prune to maintain shape, encourage bushiness, and remove dead or weak growth; best done after flowering or in late winter.
Tools
Pruning shears, loppers (for larger branches), gloves, disinfectant for tools.
Checklist
Disinfect tools; prune after flowering; remove dead or diseased wood; shape the plant evenly.
Repotting Guide
Best Season
Early spring before new growth begins; avoid repotting during dormancy.
Pot Size
Increase pot size by 2–3 inches in diameter; ensure good drainage holes.
Method
Gently remove the plant; trim any circling roots; place in a slightly larger pot with fresh soil; water thoroughly.
Suggestions
Repot every 2–3 years or when roots fill the container; beneficial for container-grown plants to refresh soil and space.
Checklist
Choose appropriate pot size; use fresh, well-draining soil; trim roots if necessary; water well after repotting.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture before watering; water deeply at the base; ensure proper drainage; adjust frequency seasonally.
How to Apply Water Properly
Water directly at the root zone until the soil is moist to a depth of 6–8 inches; ensure excess water drains away to prevent waterlogging; water early in the day to minimize fungal issues.
Watering Schedule Tips
Water deeply once per week during spring and summer; reduce frequency to every 2–3 weeks in fall and winter, adjusting based on rainfall and soil moisture.
Soil Improvement
Add compost or aged manure for fertility; incorporate perlite or sand for drainage; mulch to retain moisture and improve structure.
Temperature Stress Management
Signs of Temperature Issues
Leaf scorch or wilting in excessive heat; dieback or delayed bud break in cold stress; stunted growth in temperature extremes.
Cold Stress
Leaves may turn brown or drop; buds may fail to open; stems can become brittle in prolonged freezing conditions.
Solution: Mulch heavily around the base in winter; protect from harsh winds; avoid overwatering before freezes to prevent root damage.
Hot Stress
Leaves may wilt, scorch, or drop; growth may slow; flowers may fade quickly in intense heat.
Solution: Provide afternoon shade; increase watering frequency; use mulch to retain soil moisture; avoid fertilizing during heatwaves.
Fertilizing Guide
Fertilizing Checklist
Fertilize in spring only; use balanced formula; water well after application; avoid late-season feeding.
Fertilizing Method
Use a balanced, slow-release fertilizer in early spring; avoid high-nitrogen formulas; discontinue fertilizing in late summer to prepare for dormancy.
Common Problems & Solutions
Toxicity Warning
Cats
Non-toxicPhysocarpus capitatus is not toxic to cats. The plant does not contain any known toxic compounds that would harm felines upon ingestion.
⚡ Toxic If:
if eaten
Dogs
Non-toxicPhysocarpus capitatus is not toxic to dogs. There are no known toxic substances in the plant that would pose a health risk to canines if ingested.
⚡ Toxic If:
if eaten
Humans
Non-toxicPhysocarpus capitatus, commonly known as Pacific ninebark, is not considered toxic to humans. The plant has no known toxic compounds that would cause adverse effects upon ingestion.
⚡ Toxic If:
if eaten
Frequently Asked Questions
Q: Does Pacific Ninebark attract wildlife?
A: Yes, it attracts bees, butterflies, and birds with its flowers and habitat.
Q: Is Pacific Ninebark toxic to pets?
A: No, it is non-toxic to dogs and cats.
Q: How does the bark of Pacific Ninebark look?
A: The bark peels in strips, revealing multiple layers of reddish-brown inner bark.
Quick Reference
| Family: | Rosaceae |
| Care: | easy |
| Light: | full sun to partial shade |
| Water: | every 7–10 days during activ |
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