Boerhaave's Mullein
verbascum boerhavii
Also known as: ["Boerhaave's Mullein"]
Overview
A biennial herbaceous plant native to the Mediterranean region, known for its tall spikes of yellow flowers.
Benefits & Perks
["long-flowering","wildlife attractant (bees, butterflies, birds)","drought tolerant"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Lamiales |
| Family: | Scrophulariaceae |
| Genus: | Verbascum |
| Botanical Name: | Verbascum boerhavii |
Plant Characteristics
Basic Information
- Category: Flowers
- Suitable Location: border plantings or rock gardens in temperate climates
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"5–30°C"}
- Hardiness: {"zones":"8–10"}
- 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.
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: moderate
- Pruning Frequency: After flowering or every 2–3 months to maintain shape.
- Pruning Intensity: Moderate; remove up to one-third of the plant if overgrown, but avoid heavy pruning during flowering
Care Details
Ideal Sunlight Coverage:
Full sun to partial shade; prefers 6–8 hours of direct sunlight daily, but can tolerate some afternoon shade in hot climates.
Sunlight Tolerance Tips:
Acclimate plants gradually to intense sunlight to prevent scorching; provide afternoon shade in very hot regions; for indoor plants, place near a south-facing window with indirect light.
Care Requirements
Care Difficulty
moderatemoderate
Sunlight
full sun to partial shade
Rotate plant weekly for even growth; use sheer curtains to filter intense light; avoid placing in drafty areas.
Watering
every 7–10 days, allowing soil to dry between waterings
Water thoroughly but infrequently to encourage deep roots; ensure soil dries between waterings to prevent root rot; avoid overhead watering to reduce leaf diseases.
Soil
well-draining, sandy loam with some organic matter
pH: Slightly alkaline to neutral (pH 6.5–7.5).
Ensure pots have drainage holes; avoid heavy clay soils; top-dress with compost annually.
Temperature
Prefers moderate temperatures, 60–75°F (15–24°C). Can tolerate cooler conditions but avoid prolonged exposure below 50°F (10°C).
Protect from frost; avoid sudden temperature fluctuations; maintain consistent humidity in dry, hot conditions.
Fertilizing
every 4–6 weeks during active growth with balanced liquid fertilizer
Apply fertilizer to moist soil to prevent root burn; stop fertilizing during dormancy; flush soil occasionally to prevent salt buildup.
Propagation
Methods
Stem cuttings or seed. Stem cuttings are faster and more reliable for home growers.
Step-by-Step Propagation Guide
- Take a 4–6 inch cutting below a leaf node.
- Remove lower leaves.
- Dip in rooting hormone.
- Plant in moist medium.
- Keep humid and warm.
Best Time: Spring or early summer when the plant is actively growing.
Environment
Warm (65–75°F), humid environment with indirect light and good air circulation.
Medium
Well-draining mix of perlite and peat moss or cactus potting mix.
Hormone
Recommended to use rooting hormone to improve success rates.
Timeline
Roots typically form in 3–6 weeks; plants may take 2–3 months to establish.
Tools Needed
Pruning shears, rooting hormone, small pots, well-draining medium, plastic wrap or propagator.
Quick Tips
Use sterile tools to prevent disease; maintain consistent moisture; provide bottom heat if possible.
Pruning & Repotting
Pruning Guide
Method
Deadhead spent flowers; trim leggy stems to just above a leaf node; cut back after flowering to encourage new growth.
Pruning Plan
Prune to maintain shape, encourage bushier growth, and remove spent flowers to promote reblooming.
Tools
Pruning shears, sharp knife, gloves.
Checklist
Use clean tools; prune dead or damaged stems; cut just above a leaf node; remove spent flowers.
Repotting Guide
Best Season
Spring, before the active growing season begins.
Pot Size
Increase pot size by 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 thoroughly after repotting.
Suggestions
Repot every 2–3 years or when roots fill the pot. Necessary to refresh soil and provide more space.
Checklist
Choose a new pot with drainage holes; prepare fresh soil mix; trim roots if necessary; water after repotting.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture before watering; water deeply at the base; ensure proper drainage; avoid wetting leaves.
How to Apply Water Properly
Water directly at the base of the plant, ensuring moisture reaches the root zone. Water until it drains from the bottom, then allow the soil to dry before the next watering. Water in the morning to minimize evaporation and fungal growth.
Watering Schedule Tips
Water deeply once the top inch of soil feels dry, typically every 7–10 days in spring/summer, reducing frequency to every 2–3 weeks in fall/winter. Adjust based on rainfall and humidity.
Soil Improvement
Add perlite or coarse sand for drainage; incorporate compost for fertility; use a cactus or succulent mix as a base.
Temperature Stress Management
Signs of Temperature Issues
Chlorosis (yellowing leaves), wilting, stunted growth, or bud drop in extreme heat or cold.
Cold Stress
Low temperatures can slow growth, cause leaf discoloration, and increase susceptibility to root rot if soil remains wet.
Solution: Move potted plants indoors or to a sheltered location; provide a layer of mulch to insulate roots; avoid overwatering in cold conditions.
Hot Stress
Excessive heat can lead to wilting, leaf scorch, and reduced flowering, especially if combined with drought stress.
Solution: Provide afternoon shade; increase watering frequency; use mulch to retain soil moisture; ensure good air circulation.
Fertilizing Guide
Fertilizing Checklist
Use diluted fertilizer; apply during active growth; avoid winter feeding; flush soil periodically.
Fertilizing Method
Use a balanced, water-soluble fertilizer diluted to half strength every 4–6 weeks during the growing season (spring/summer). Avoid fertilizing in fall/winter.
Common Problems & Solutions
Toxicity Warning
Cats
Slightly ToxicCats that ingest Verbascum boerhavii may experience mild gastrointestinal irritation. The plant's saponins can cause discomfort, though severe toxicity is rare.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Dogs
Slightly ToxicIngestion of Verbascum boerhavii by dogs may lead to mild gastrointestinal upset due to the presence of saponins. While not typically life-threatening, ingestion should be monitored.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Humans
Slightly ToxicVerbascum boerhavii contains saponins and other compounds that can cause mild gastrointestinal distress when ingested in significant quantities. The plant's effects are generally not severe but can be problematic for sensitive individuals.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Frequently Asked Questions
Q: Is Verbascum boerhavii toxic to pets?
A: There is no reliable information available regarding its toxicity to pets.
Q: How tall does Verbascum boerhavii grow?
A: It typically grows to a height of 1–2 meters.
Q: Does Verbascum boerhavii require full sun?
A: Yes, it thrives in full sun conditions.
Quick Reference
| Family: | Scrophulariaceae |
| Care: | moderate |
| Light: | full sun to partial shade |
| Water: | every 7–10 days, allowing so |
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