Spanish gromwell
onosma tricerosperma
Also known as: ["Gromwell","False Gromwell"]
Overview
A perennial herbaceous plant native to the Iberian Peninsula, known for its yellow flowers and woolly stems.
Benefits & Perks
["wildlife attractant (bees, butterflies, birds)","drought tolerant","rare/collector’s item"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Boraginales |
| Family: | Boraginaceae |
| Genus: | Onosma |
| Botanical Name: | Onosma tricerosperma |
Plant Characteristics
Basic Information
- Category: Flowers
- Suitable Location: rock garden or sunny border
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"5–35°C"}
- Hardiness: {"zones":"7–9"}
- Misting: rarely required, only if ambient humidity is very low
- Drainage: Fast-draining to prevent waterlogging.
- Soil Type: Well-draining, sandy loam with some organic matter.
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: moderate
- Pruning Frequency: Annually in late winter or early spring; light pruning can be done as needed.
- Pruning Intensity: Moderate; remove up to one-third of the plant if overgrown.
Care Details
Ideal Sunlight Coverage:
Full sun (6–8 hours/day); tolerates partial shade but blooms best in direct light.
Sunlight Tolerance Tips:
Acclimate gradually if moving from shade to sun; protect from intense midday sun in hot climates; ensure good air circulation to prevent leaf burn.
Care Requirements
Care Difficulty
moderatemoderate
Sunlight
full sun
Rotate plant for even light exposure; use sheer curtains to filter harsh sun; avoid placing near reflective surfaces that intensify light.
Watering
every 7–10 days during active growth, reduce in winter
Water thoroughly but infrequently; ensure soil dries between waterings; avoid overhead watering to prevent fungal issues.
Soil
well-drained, sandy loam with low fertility
pH: Slightly alkaline (pH 7.0–7.5).
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 nights but avoid frost.
Avoid sudden temperature changes; protect from drafts; maintain consistent room temperature indoors.
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; stop fertilizing if plant shows signs of stress.
Propagation
Methods
Stem cuttings or seed; stem cuttings are more reliable for home growers.
Step-by-Step Propagation Guide
- Take a 4–6 inch cutting.
- Remove lower leaves.
- Dip in rooting hormone.
- Plant in medium.
- Keep moist and warm.
Best Time: Spring or early summer when the plant is actively growing.
Environment
Warm (70–75°F/21–24°C), high humidity (70–80%), and bright indirect light.
Medium
Well-draining mix of perlite and peat moss or cactus mix.
Hormone
Recommended to use rooting hormone for faster root development.
Timeline
Roots may develop in 3–6 weeks; establish in new pot after 2–3 months.
Tools Needed
Pruning shears, rooting hormone, small pots, well-draining medium.
Quick Tips
Use healthy, non-flowering stems; maintain consistent moisture; provide bottom heat if possible.
Pruning & Repotting
Pruning Guide
Method
Pinch back tips for bushiness; cut just above a leaf node or bud.
Pruning Plan
Prune to maintain shape, encourage bushier growth, and remove dead or diseased parts.
Tools
Clean, sharp pruning shears or scissors.
Checklist
Disinfect tools; prune dead/damaged growth; 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) than the current one.
Method
Remove plant gently; trim roots if necessary; place in new pot with fresh soil; water lightly.
Suggestions
Repot every 2–3 years or when roots fill the pot; beneficial for growth and drainage.
Checklist
Prepare new pot with drainage holes; trim roots if crowded; use fresh soil mix; water after repotting.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture; water deeply; ensure drainage; avoid wetting foliage.
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 and fungal risk.
Watering Schedule Tips
Water deeply once the top inch of soil is dry; reduce frequency in winter to prevent root rot.
Soil Improvement
Add perlite or coarse sand to improve drainage; incorporate compost for fertility.
Temperature Stress Management
Signs of Temperature Issues
Wilting, leaf drop, or stunted growth in extreme heat; yellowing or browning leaves in cold stress.
Cold Stress
Slows growth, may cause leaf discoloration, and can lead to root damage if temperatures drop below 50°F (10°C).
Solution: Move to a warmer location; provide frost protection if outdoors; reduce watering in cold conditions.
Hot Stress
Leaves may scorch, wilt, or drop; growth may slow due to excessive heat.
Solution: Provide shade during peak heat; increase humidity; water more frequently but avoid waterlogging.
Fertilizing Guide
Fertilizing Checklist
Check fertilizer type; dilute properly; apply during active growth; avoid winter feeding.
Fertilizing Method
Use a balanced, water-soluble fertilizer diluted to half strength; fertilize every 4–6 weeks during growing season (spring/summer); avoid fertilizing in winter.
Common Problems & Solutions
Toxicity Warning
Cats
Slightly ToxicCats may experience mild gastrointestinal upset if they consume Onosma tricerosperma. The plant's compounds can irritate the digestive system, but severe reactions are uncommon.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Dogs
Slightly ToxicIn dogs, ingestion of Onosma tricerosperma can lead to mild gastrointestinal upset. The plant's compounds may cause irritation in the digestive tract, though severe toxicity is rare.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Humans
Slightly ToxicOnosma tricerosperma contains compounds that can cause mild gastrointestinal distress and allergic reactions in humans. The plant's effects are generally not severe but can be problematic for individuals with sensitive digestive systems or allergies.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Frequently Asked Questions
Q: Is Onosma tricerosperma toxic to pets?
A: There is no reliable information available regarding its toxicity to pets.
Q: How often should Onosma tricerosperma be watered?
A: Water sparingly, allowing the soil to dry out between waterings, as it is drought-tolerant.
Q: Does Onosma tricerosperma attract wildlife?
A: Yes, it attracts bees, butterflies, and birds, making it a valuable addition to wildlife gardens.
Quick Reference
| Family: | Boraginaceae |
| Care: | moderate |
| Light: | full sun |
| Water: | every 7–10 days during activ |
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