Sosnowsky's hogweed
heracleum sosnowskyi
Also known as: ["Giant hogweed","Poison hemlock"]
Overview
A large, biennial herbaceous plant native to the Caucasus region, known for its phototoxic sap that can cause severe skin burns and blisters upon exposure to sunlight.
Benefits & Perks
["wildlife attractant (bees, butterflies, birds)"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Apiales |
| Family: | Apiaceae |
| Genus: | Heracleum |
| Botanical Name: | Heracleum sosnowskyi |
Plant Characteristics
Basic Information
- Category: Herbs & Weeds
- Suitable Location: garden bed in temperate climates, avoid highly disturbed areas
- Suitable For:
- Is Weed: No
- Allergenicity: high
Environmental Needs
- Climate: {"temperatureRange":"–30–30°C"}
- Hardiness: {"zones":"3–7"}
- Misting: rarely required
- Drainage: Moderate to well-draining; avoid waterlogged conditions.
- Soil Type: Rich, well-draining soil with organic matter; can tolerate slightly heavier soils if well-aerated.
Maintenance Level
- Maintenance Level: very high
- Toughness Level: very low
- Pruning Frequency: As needed, typically after flowering or when plant becomes leggy; light pruning can be done throughout the growing season.
- Pruning Intensity: Light to moderate; avoid heavy pruning unless necessary to control size or shape.
Care Details
Ideal Sunlight Coverage:
Full sun to partial shade; 6–8 hours of direct sunlight per day; adjust for intense summer sun.
Sunlight Tolerance Tips:
Acclimate plants gradually to intense sunlight; protect from scorching midday sun; provide shade during extreme heat.
Care Requirements
Care Difficulty
expert onlymoderate
Sunlight
full sun to partial shade
Rotate plant for even light exposure; use sheer curtains to filter intense sun; avoid placing in drafty areas.
Watering
every 7–10 days during active growth, less frequently in winter
Water thoroughly until it drains from the bottom; allow soil to dry between waterings; avoid overwatering.
Soil
fertile, moist, well-drained loam
pH: Slightly acidic to neutral (pH 6.0–7.0).
Use a mix of potting soil and perlite; avoid heavy clay soils; ensure pots have drainage holes.
Temperature
Prefers cool to moderate temperatures (60–75°F or 15–24°C); tolerates cooler nights; avoid extreme heat or cold.
Monitor temperature fluctuations; protect from drafts; adjust watering based on temperature.
Fertilizing
every 4–6 weeks during growing season, none in winter
Apply fertilizer to moist soil to prevent root burn; flush soil occasionally to prevent salt buildup; reduce frequency in dormant periods.
Propagation
Methods
Stem cuttings or seed; stem cuttings are more reliable for home growers.
Step-by-Step Propagation Guide
- Take a healthy cutting.
- Apply rooting hormone.
- Plant in medium.
- Maintain humidity.
- Wait for roots to develop.
Best Time: Spring or early summer when the plant is actively growing.
Environment
Warm, humid environment with indirect light; maintain consistent moisture.
Medium
Well-draining potting mix with perlite or sand; can also root in water initially.
Hormone
Rooting hormone is recommended to improve success rates.
Timeline
Roots may develop in 2–4 weeks; new growth may appear in 6–8 weeks.
Tools Needed
Pruning shears, rooting hormone, small pots, misting spray bottle.
Quick Tips
Use healthy, non-flowering stems; keep cuttings out of direct sun; maintain high humidity for faster rooting.
Pruning & Repotting
Pruning Guide
Method
Use clean cuts just above a leaf node or bud; remove dead or yellowing leaves; trim back overgrown stems.
Pruning Plan
Prune to maintain shape, encourage bushier growth, and remove dead or diseased parts; focus on removing spent flower stalks.
Tools
Pruning shears, sterilizing solution, gloves.
Checklist
Sterilize tools; prune dead or diseased parts; shape the plant; clean up debris.
Repotting Guide
Best Season
Spring, before the active growing season begins.
Pot Size
Choose a pot one size larger (1–2 inches wider in diameter) than the current one.
Method
Remove plant gently; trim any circling roots; place in a new pot with fresh soil; water thoroughly after repotting.
Suggestions
Repot every 2–3 years or when roots fill the pot; necessary to refresh soil and provide more space.
Checklist
Prepare new pot with drainage holes; trim roots if necessary; use fresh potting mix; water after repotting.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture; water deeply; ensure drainage; adjust for season.
How to Apply Water Properly
Water directly at the root zone, ensuring even moisture distribution; water early in the morning to reduce 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 sand for drainage; incorporate compost for fertility; ensure good aeration by avoiding compacted soil.
Temperature Stress Management
Signs of Temperature Issues
Wilting, yellowing leaves, stunted growth, or leaf drop; may show signs of stress during heatwaves or cold snaps.
Cold Stress
Low temperatures can slow growth and cause leaf discoloration; prolonged cold may lead to root damage or death.
Solution: Move to a warmer location; provide a protective cover during frost; ensure soil does not freeze.
Hot Stress
Excessive heat can cause leaf scorch, wilting, or premature flowering; may lead to dehydration.
Solution: Provide shade during peak heat; increase watering frequency; improve air circulation around the plant.
Fertilizing Guide
Fertilizing Checklist
Check fertilizer type; dilute correctly; apply during active growth; avoid winter feeding.
Fertilizing Method
Use a balanced liquid fertilizer diluted to half strength; fertilize every 4–6 weeks during the growing season (spring to early fall); avoid fertilizing in winter.
Common Problems & Solutions
Toxicity Warning
Cats
Highly ToxicCats are highly sensitive to the furanocoumarins in Heracleum sosnowskyi, which can cause severe photodermatitis upon contact with skin followed by sunlight exposure. The reaction can lead to painful skin lesions and potential eye damage.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if touched, especially with sunlight exposure
Dogs
Highly ToxicSimilar to humans, dogs are susceptible to severe photodermatitis when exposed to the furanocoumarins in Heracleum sosnowskyi, particularly after contact with sunlight. This can cause painful skin reactions and potential eye damage.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if touched, especially with sunlight exposure
Humans
Highly ToxicHeracleum sosnowskyi contains furanocoumarins that cause severe photodermatitis upon contact with skin followed by exposure to ultraviolet light. The reaction leads to severe blistering, burns, and long-term skin damage.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if touched, especially with sunlight exposure
Frequently Asked Questions
Q: Is Sosnowsky's hogweed safe to grow in a garden?
A: No, it is highly toxic and invasive, posing significant risks to humans, pets, and ecosystems.
Q: What are the dangers of this plant?
A: Its sap can cause severe burns and blisters upon contact with skin and sunlight, and it is highly toxic if ingested.
Q: How can I identify Sosnowsky's hogweed?
A: It is a tall plant with large, lobed leaves, white umbrella-shaped flowers, and hollow, ridged stems often spotted with purple.
Quick Reference
| Family: | Apiaceae |
| Care: | expert only |
| Light: | full sun to partial shade |
| Water: | every 7–10 days during activ |
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