Prickly Lettuce

lactuca virosa

Also known as: ["Wild Lettuce","Opium Lettuce"]

Family: Asteraceae Genus: Lactuca Category: Herbs & Weeds

Overview

A tall, biennial herb with spiny leaves and milky sap, known for its sedative properties.

Benefits & Perks

["medicinal use","wildlife attractant (bees, butterflies, birds)"]

Botanical Classification

Phylum: Magnoliophyta
Class: Magnoliopsida
Order: Asterales
Family: Asteraceae
Genus: Lactuca
Botanical Name: Lactuca virosa

Plant Characteristics

Basic Information
  • Category: Herbs & Weeds
  • Suitable Location: garden bed or container in a location with good air circulation
  • Suitable For:
    Collectors & Enthusiasts Wildlife Supporters
  • Is Weed: No
  • Allergenicity: low
Environmental Needs
  • Climate: {"temperatureRange":"5–30°C"}
  • Hardiness: {"zones":"5–9"}
  • Misting: rarely required, only if ambient humidity is very low
  • Drainage: Fast-draining to prevent waterlogging.
  • Soil Type: Well-draining, loamy soil with added organic matter; avoid heavy clay.
Maintenance Level
  • Maintenance Level: low
  • Toughness Level: moderate
  • Pruning Frequency: As needed during the growing season; after flowering to maintain shape.
  • Pruning Intensity: Light to moderate; remove only dead or overgrown stems unless shaping is required.
Care Details

Ideal Sunlight Coverage:
Full sun (6–8 hours/day) in cooler climates; partial shade in hot regions to prevent scorching.

Sunlight Tolerance Tips:
Acclimate plants gradually to intense sunlight; provide shade during peak afternoon heat; adjust placement based on seasonal light intensity.

Warning Signs: Yellowing leaves (overwatering), stunted growth (nutrient deficiency), or root rot (poor drainage).

Care Requirements

Care Difficulty
easy

moderate

Sunlight

full sun to partial shade

Rotate plants for even light exposure; use shade cloth in hot climates; avoid direct midday sun in summer.

Watering

every 7–10 days, allowing soil to dry between waterings

Water thoroughly but infrequently; ensure soil dries between waterings; avoid wetting foliage.

Soil

well-draining, loamy soil with moderate organic content

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

Use raised beds in heavy soils; avoid over-amending with peat in hot climates; test pH annually.

Temperature

Prefers cool to moderate temperatures (60–75°F or 15–24°C); tolerates cooler nights but avoids extreme heat.

Protect from frost; shield from intense summer heat; maintain consistent temperatures for optimal growth.

Fertilizing

every 4–6 weeks during growing season with balanced liquid fertilizer

Apply fertilizer after watering to prevent root burn; stop feeding during dormancy; use organic options for gentle nutrients.

Propagation

Methods

Stem cuttings or seed; cuttings root easily in warm conditions.

Step-by-Step Propagation Guide
  1. Take a 4–6 inch cutting.
  2. Remove lower leaves.
  3. Dip in rooting hormone.
  4. Plant in medium.
  5. Keep moist and warm.

Best Time: Spring or early summer when temperatures are mild and growth is active.

Environment

Warm (70–75°F or 21–24°C), humid, and bright but indirect light.

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, small pots, misting spray bottle.

Quick Tips

Use sterile tools to prevent disease; maintain high humidity with a propagator or plastic bag; avoid overwatering.

Pruning & Repotting

Pruning Guide
Method

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

Pruning Plan

Prune to encourage bushier growth and remove spent flowers to prevent self-seeding.

Tools

Clean, sharp pruning shears or scissors.

Checklist

Sterilize tools; prune in early morning; remove dead/damaged growth; avoid over-pruning.

Repotting Guide
Best Season

Spring, before the active growing season begins.

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 new pot with fresh soil; water lightly.

Suggestions

Repot every 1–2 years or when roots fill the container; beneficial for young plants to support growth.

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; water deeply; ensure drainage; avoid wetting leaves.

How to Apply Water Properly

Water at the base of the plant, ensuring moisture reaches the root zone; allow excess water to drain away; water in the morning to reduce evaporation.

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 deeply once the top inch of soil feels dry; reduce frequency in winter to prevent root rot.

Soil Improvement

Add perlite or coarse sand for drainage; incorporate compost for fertility; ensure aeration with organic matter.

Temperature Stress Management
Signs of Temperature Issues

Wilting, yellowing leaves, stunted growth, or bolting (premature flowering) in response to stress.

Cold Stress

Slows growth and may cause leaf damage or dieback in prolonged cold; prefers frost-free conditions.

Solution: Provide frost protection (e.g., row covers); move potted plants indoors; avoid planting in late fall.

Hot Stress

Leaves may wilt, turn yellow, or develop sunburn; growth may become leggy or bolt prematurely.

Solution: Provide afternoon shade; increase watering; use mulch to retain soil moisture; ensure good air circulation.

Fertilizing Guide
Fertilizing Checklist

Check fertilizer type; dilute correctly; apply to moist soil; avoid foliage contact.

Fertilizing Method

Use a balanced, water-soluble fertilizer diluted to half strength every 4–6 weeks during the growing season; avoid fertilizing in winter.

Common Problems & Solutions

Yellowing leaves in Lactuca virosa may indicate nutrient deficiencies, overwatering, or pest infestations, affecting photosynthesis and overall plant health.

Wilting in Lactuca virosa can be caused by water stress, root damage, or pathogen infection, leading to reduced turgor pressure and potential plant death if not addressed.

Leaf spots on Lactuca virosa are typically caused by fungal or bacterial infections, leading to reduced photosynthetic capacity and potential defoliation.

Rotting, particularly root or stem rot, in Lactuca virosa is often due to excessive moisture or fungal pathogens, causing decay and eventual plant death.

Toxicity Warning

Cats
Toxic

Cats are highly sensitive to the narcotic compounds in Lactuca virosa, which can cause severe neurological and gastrointestinal effects, including respiratory distress.

⚠️ Symptoms:
vomiting diarrhea lethargy difficulty breathing tremors seizures
🌿 Toxic Parts:
leaves stems roots
⚡ Toxic If:

if eaten

Prevent cats from accessing the plant. Contact a veterinarian promptly if ingestion is suspected.
Dogs
Toxic

In dogs, ingestion of Lactuca virosa can lead to gastrointestinal upset, neurological symptoms, and potential respiratory depression due to the plant's narcotic compounds.

⚠️ Symptoms:
vomiting diarrhea lethargy difficulty breathing tremors
🌿 Toxic Parts:
leaves stems roots
⚡ Toxic If:

if eaten

Keep plants away from dogs. If ingestion is suspected, seek veterinary attention immediately.
Humans
Toxic

Lactuca virosa contains lactucarium, a resinous substance with narcotic properties that can cause central nervous system depression, respiratory issues, and gastrointestinal distress. The plant's milky sap is particularly potent.

⚠️ Symptoms:
drowsiness respiratory depression nausea vomiting abdominal pain skin irritation
🌿 Toxic Parts:
leaves stems roots
⚡ Toxic If:

if eaten

Avoid ingestion. Handle with gloves to prevent skin contact with the sap. Keep out of reach of children and pets.
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 Lactuca virosa safe for consumption?

A: While parts of the plant have been used medicinally, it is mildly toxic and should not be consumed without proper knowledge.

Q: Does Prickly Lettuce attract wildlife?

A: Yes, it attracts bees, butterflies, and birds, making it beneficial for wildlife gardens.

Q: How should I care for Lactuca virosa?

A: It is easy to grow and requires low maintenance, thriving in well-drained soil and full sun.

Quick Reference
Family: Asteraceae
Care: easy
Light: full sun to partial shade
Water: every 7–10 days, allowing so
Suitable For: ["collectors/enthusiasts","wildlife supporters (attracts bees, butterflies, birds)"]
Get Expert Care Tips

Download the Plantious app for personalized care reminders and plant identification!

Google Play App Store
Share This Plant

Related Plants

Mexican zinnia
View
Pale Ragwort
View
Western Thistle
View
Spiny Cocklebur
View