Western Water Hemlock
oenanthe sarmentosa
Also known as: ["Water Dropwort","Western Water Dropwort"]
Overview
A perennial herbaceous plant native to western North America, typically found in wetland habitats. It is known for its hollow stems and compound leaves, and is highly toxic due to the presence of cicutoxin.
Benefits & Perks
["wildlife attractant (bees, butterflies, birds)"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Apiales |
| Family: | Apiaceae |
| Genus: | Oenanthe |
| Botanical Name: | Oenanthe sarmentosa |
Plant Characteristics
Basic Information
- Category: Herbs & Weeds
- Suitable Location: moist garden beds, near water features, or in containers with consistent moisture
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"0–30°C"}
- Hardiness: {"zones":"6–9"}
- Misting: rarely required, only if ambient humidity is very low
- Drainage: Moderately well-draining; prefers consistently moist soil but not waterlogged.
- Soil Type: Rich, moist, well-draining soil with organic matter (e.g., compost or peat moss).
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: moderate
- Pruning Frequency: As needed, typically every 2–3 months or after flowering.
- Pruning Intensity: Moderate; remove up to one-third of the plant if overgrown.
Care Details
Ideal Sunlight Coverage:
Partial shade to full sun (4–6 hours of direct sun or bright indirect light); prefers cooler conditions.
Sunlight Tolerance Tips:
Acclimate gradually to direct sun to avoid leaf burn; protect from intense afternoon sun; suitable for shaded garden beds or containers in partial shade.
Care Requirements
Care Difficulty
moderatemoderate
Sunlight
partial shade to full shade
Morning sun is ideal; provide shade during peak heat; rotate pots for even growth.
Watering
every 3–5 days during active growth, reduce in winter
Water deeply to encourage root growth; ensure proper drainage to avoid waterlogging; adjust frequency based on season and weather.
Soil
moist, rich, loamy soil with good organic content
pH: Slightly acidic to neutral (pH 6.0–7.0).
Avoid heavy clay soils; maintain consistent moisture; enrich with organic matter annually.
Temperature
Cool to moderate temperatures (50–75°F or 10–24°C); thrives in cooler climates.
Avoid sudden temperature fluctuations; keep away from heat sources; maintain humidity in dry conditions.
Fertilizing
every 4–6 weeks during growing season
Fertilize after watering to prevent root burn; flush soil occasionally to prevent salt buildup; use organic options like compost tea.
Propagation
Methods
Stem cuttings or division; stem cuttings are more common for home growers.
Step-by-Step Propagation Guide
- Take 4–6 inch cuttings.
- Remove lower leaves.
- Dip in rooting hormone (optional).
- Plant in moist medium.
- Maintain humidity.
Best Time: Spring or early summer when the plant is actively growing.
Environment
High humidity (70–90%), indirect light, and consistent warmth (65–75°F or 18–24°C).
Medium
Moist, well-draining soil mix (e.g., peat moss and perlite) or water propagation.
Hormone
Optional, but rooting hormone can improve success rates.
Timeline
Roots typically form in 2–4 weeks; new growth may appear in 6–8 weeks.
Tools Needed
Pruning shears, rooting hormone, small pots, humidity dome or plastic bag.
Quick Tips
Use healthy, non-flowering stems; keep soil consistently moist; provide bottom heat for faster rooting.
Pruning & Repotting
Pruning Guide
Method
Pinch back tips for bushier growth; cut stems just above a leaf node or bud.
Pruning Plan
Prune to maintain shape, encourage bushier growth, and remove dead or damaged stems.
Tools
Clean, sharp pruning shears or scissors.
Checklist
Sterilize tools before use; prune in early morning; dispose of pruned material to prevent disease spread.
Repotting Guide
Best Season
Spring, before the active growing season begins.
Pot Size
Choose a pot 1–2 inches larger in diameter than the current one.
Method
Remove plant gently; trim any circling roots; place in a new pot with fresh soil; water lightly after repotting.
Suggestions
Repot every 1–2 years or when roots fill the pot; beneficial for root health and growth.
Checklist
Use fresh, well-draining soil; ensure pot has drainage holes; avoid overwatering after repotting.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture before watering; water early in the day; ensure pots have drainage holes.
How to Apply Water Properly
Water at the base of the plant, focusing on the root zone; apply until water begins to drain from the bottom; avoid wetting foliage to prevent fungal issues.
Watering Schedule Tips
Water regularly, keeping soil consistently moist but not waterlogged; reduce frequency in winter to prevent root rot.
Soil Improvement
Add compost or peat moss to improve moisture retention; mix in perlite or sand for better drainage.
Temperature Stress Management
Signs of Temperature Issues
Wilting, yellowing leaves, or stunted growth in excessive heat; leaf drop or root rot in cold or waterlogged conditions.
Cold Stress
Slows growth and may cause leaf damage or dieback in temperatures below 40°F (4°C); susceptible to frost.
Solution: Protect with frost cloth or mulch in cold climates; avoid overwatering in cool conditions.
Hot Stress
Leaves may scorch, wilt, or drop in excessive heat; growth may stall.
Solution: Provide shade during peak heat; increase watering frequency; improve air circulation.
Fertilizing Guide
Fertilizing Checklist
Check fertilizer label for NPK ratio; water before fertilizing; apply in early morning or evening.
Fertilizing Method
Use a balanced liquid fertilizer diluted to half strength; apply every 4–6 weeks during growing season (spring to early fall); avoid fertilizing in winter.
Common Problems & Solutions
Toxicity Warning
Cats
Slightly ToxicCats may experience mild gastrointestinal and neurological symptoms upon ingestion of Oenanthe sarmentosa. The plant is not typically fatal to cats but can cause significant discomfort.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Dogs
Slightly ToxicIn dogs, ingestion of Oenanthe sarmentosa can lead to mild gastrointestinal upset and neurological disturbances. While rarely fatal, symptoms can cause discomfort and require veterinary attention.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Humans
Slightly ToxicOenanthe sarmentosa contains compounds that can cause mild gastrointestinal distress and neurological symptoms if ingested in significant quantities. The plant's effects are generally not life-threatening but can be unpleasant.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Frequently Asked Questions
Q: Is Oenanthe sarmentosa safe for pets?
A: No, it is highly toxic to dogs and cats.
Q: Where does Oenanthe sarmentosa grow naturally?
A: It is native to wetland habitats in western North America.
Q: What are the common problems with this plant?
A: Common issues include yellow leaves, wilting, and rotting.
Quick Reference
| Family: | Apiaceae |
| Care: | moderate |
| Light: | partial shade to full shade |
| Water: | every 3–5 days during active |
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