Tansy Ragwort

senecio jacobaea

Also known as: ["St. James-wort","Stinking Nanny","Stinking Willie"]

Family: Asteraceae Genus: Senecio Category: Herbs & Weeds

Overview

A highly toxic, invasive herbaceous plant with bright yellow composite flowers and deeply lobed leaves.

Benefits & Perks

["wildlife attractant (bees, butterflies, birds)","drought tolerant"]

Botanical Classification

Phylum: Magnoliophyta
Class: Magnoliopsida
Order: Asterales
Family: Asteraceae
Genus: Senecio
Botanical Name: Senecio jacobaea

Plant Characteristics

Basic Information
  • Category: Herbs & Weeds
  • Suitable Location: garden bed or container in open, sunny area
  • Suitable For:
    Collectors & Enthusiasts Outdoor Landscapers
  • Is Weed: No
  • Allergenicity: moderate
Environmental Needs
  • Climate: {"temperatureRange":"5–30°C"}
  • Hardiness: {"zones":"6–9"}
  • Misting: rarely required, only if ambient humidity is very low
  • Drainage: Fast-draining to prevent waterlogging.
  • Soil Type: Well-draining potting mix with added perlite or sand for aeration.
Maintenance Level
  • Maintenance Level: very low
  • Toughness Level: high
  • Pruning Frequency: Every 2–3 months during active growth; as needed to remove spent flowers or damaged foliage.
  • Pruning Intensity: Moderate; remove up to one-third of the plant if overgrown.
Care Details

Ideal Sunlight Coverage:
Bright indirect light for 6–8 hours daily; can tolerate some direct morning sun but avoid harsh afternoon sun.

Sunlight Tolerance Tips:
Acclimate gradually to direct light; protect from intense midday sun; adjust placement seasonally to avoid excessive heat or cold.

Warning Signs: Yellowing leaves, root rot, or stunted growth indicate poor drainage or incorrect soil conditions.

Care Requirements

Care Difficulty
moderate

moderate

Sunlight

full sun to partial shade

Rotate plant weekly for even growth; use sheer curtains to filter intense light; move outdoors in spring/summer for stronger light.

Watering

every 7–10 days during active growth, reduce in winter

Water deeply but infrequently; ensure soil dries out between waterings; avoid overhead watering to prevent fungal issues.

Soil

well-drained, sandy loam

pH: Slightly acidic to neutral (pH 6.0–7.0).

Ensure pots have drainage holes; avoid heavy clay soils; top-dress with fresh soil annually.

Temperature

Prefers 60–75°F (15–24°C); tolerates cooler temperatures but avoid frost; thrives in moderate warmth with good air circulation.

Avoid placing near drafty windows or heat vents; maintain consistent temperatures; adjust care based on seasonal changes.

Fertilizing

every 4–6 weeks during growing season, none in winter

Fertilize only when actively growing; flush soil occasionally to prevent salt buildup; stop fertilizing before winter dormancy.

Propagation

Methods

Stem cuttings in spring or early summer.

Step-by-Step Propagation Guide
  1. Take a 4–6 inch cutting.
  2. Remove lower leaves.
  3. Let cut end callous for a day.
  4. Plant in medium.
  5. Keep moist and warm.

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 mix of perlite and peat moss or cactus potting mix.

Hormone

Optional but recommended for faster rooting.

Timeline

Roots develop in 2–4 weeks; new growth appears in 6–8 weeks.

Tools Needed

Pruning shears, rooting hormone (optional), small pots, well-draining medium.

Quick Tips

Use healthy, non-flowering stems; keep cuttings out of direct sun; maintain humidity with a plastic cover.

Pruning & Repotting

Pruning Guide
Method

Pinch back tips for bushier growth; cut stems just above a leaf node or lateral branch.

Pruning Plan

Prune to maintain shape, encourage bushier growth, and remove dead or diseased parts.

Tools

Clean, sharp pruning shears or scissors.

Checklist

Sterilize tools; prune during active growth; remove dead/damaged parts; shape as desired.

Repotting Guide
Best Season

Spring, before the active growth period begins.

Pot Size

One size larger pot (e.g., +2–3 inches in diameter).

Method

Remove plant gently; trim any circling roots; place in a slightly larger pot with fresh, well-draining soil; water lightly.

Suggestions

Repot every 2–3 years or when roots fill the pot; beneficial for preventing root-bound conditions.

Checklist

Choose appropriate pot size; prepare fresh soil mix; handle roots carefully; water after repotting.

Advanced Care Tips

Watering Mastery
Watering Checklist

Check soil moisture before watering; water deeply; ensure drainage; avoid wetting foliage.

How to Apply Water Properly

Water at the base of the plant, targeting the root zone; ensure water penetrates deeply but does not pool; water in the morning to allow foliage to dry.

Pro Tip: Use a watering can with a narrow spout to direct water to the roots without disturbing the soil surface.
Watering Schedule Tips

Water moderately during active growth (spring-summer), allowing soil to dry between waterings; reduce frequency in fall-winter to prevent root rot.

Soil Improvement

Add perlite, coarse sand, or orchid bark to improve drainage; incorporate organic matter like compost for fertility.

Temperature Stress Management
Signs of Temperature Issues

Wilting, yellowing leaves, or stunted growth in cold; leaf scorch or dropping in excessive heat.

Cold Stress

Slows growth, causes leaf discoloration, and increases susceptibility to root rot due to reduced water uptake.

Solution: Move to a warmer location; protect from drafts; reduce watering in cool conditions.

Hot Stress

Leaves may scorch, wilt, or drop; growth may slow due to excessive water loss and heat stress.

Solution: Provide shade during peak heat; increase humidity; water more frequently but avoid waterlogging.

Fertilizing Guide
Fertilizing Checklist

Check growth phase before fertilizing; dilute fertilizer correctly; apply to moist soil; avoid contact with foliage.

Fertilizing Method

Use a balanced liquid fertilizer diluted to half strength every 4–6 weeks during spring and summer; avoid fertilizing in fall and winter.

Common Problems & Solutions

Yellowing leaves can indicate nutrient deficiencies, water stress, or pathogen infection, which may affect the plant's photosynthetic efficiency and overall vigor.

Wilting is often a sign of water stress, either due to insufficient water uptake or root damage, which can lead to reduced turgor pressure and impaired physiological functions.

Leaf spots are commonly caused by fungal or bacterial pathogens, resulting in necrotic lesions that can reduce photosynthetic area and weaken the plant structure.

Rotting, particularly root or stem rot, is typically caused by fungal pathogens or excessive moisture, leading to tissue decay, impaired nutrient transport, and potential plant death.

Toxicity Warning

Cats
Toxic

Cats are highly susceptible to the hepatotoxic effects of pyrrolizidine alkaloids found in Senecio jacobaea. Even small amounts can cause significant liver damage, leading to chronic health issues or death.

⚠️ Symptoms:
vomiting anorexia lethargy jaundice hepatic encephalopathy
🌿 Toxic Parts:
leaves stems flowers roots
⚡ Toxic If:

if eaten

Ensure cats cannot access this plant. Immediate veterinary care is required if ingestion is suspected. Remove the plant from environments accessible to cats.
Dogs
Toxic

In dogs, ingestion of Senecio jacobaea can lead to severe liver damage due to the presence of pyrrolizidine alkaloids. The toxicity is cumulative, meaning repeated exposure can result in progressive liver dysfunction.

⚠️ Symptoms:
vomiting diarrhea lethargy jaundice weight loss
🌿 Toxic Parts:
leaves stems flowers roots
⚡ Toxic If:

if eaten

Keep dogs away from this plant. If ingestion is suspected, seek veterinary attention immediately. Prevent access to areas where the plant grows.
Humans
Toxic

Senecio jacobaea, commonly known as ragwort, contains pyrrolizidine alkaloids which are hepatotoxic, causing liver damage and potentially leading to cirrhosis or liver failure upon chronic ingestion. These compounds are cumulative and can cause severe physiological harm even in small doses over time.

⚠️ Symptoms:
nausea vomiting abdominal pain jaundice liver failure
🌿 Toxic Parts:
leaves stems flowers roots
⚡ Toxic If:

if eaten

Avoid ingestion at all costs. Wear gloves when handling to prevent skin contact, and ensure proper disposal to prevent accidental consumption by humans or animals.
Important: Keep this plant out of reach of children and pets. If ingestion occurs, contact poison control or veterinary services immediately.

Frequently Asked Questions

Q: Is Senecio jacobaea safe for pets?

A: No, it is highly toxic to dogs and cats.

Q: Why is this plant considered a weed?

A: It is invasive, toxic to livestock, and can outcompete native species.

Q: Does it have any medicinal uses?

A: Historically used in folk medicine, but modern use is discouraged due to toxicity.

Quick Reference
Family: Asteraceae
Care: moderate
Light: full sun to partial shade
Water: every 7–10 days during activ
Suitable For: ["collectors/enthusiasts","outdoor landscapers"]
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