Tall Mexican Sunflower
tithonia diversifolia
Also known as: ["Tree Marigold","Mexican Sunflower"]
Overview
A large, vigorous shrub or small tree native to Mexico and Central America, known for its bright orange flowers and rapid growth.
Benefits & Perks
["long-flowering","deer resistant","wildlife attractant (bees, butterflies, birds)","drought tolerant"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Asterales |
| Family: | Asteraceae |
| Genus: | Tithonia |
| Botanical Name: | Tithonia diversifolia |
Plant Characteristics
Basic Information
- Category: Flowers
- Suitable Location: garden bed or border in full sun
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"15–35°C"}
- Hardiness: {"zones":"9–11"}
- Misting: rarely required
- Drainage: Well-draining to prevent root rot; avoid waterlogged conditions.
- Soil Type: Rich, loamy soil with good organic matter; can tolerate poor soils but performs best with amendments.
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: high
- Pruning Frequency: Annually in late winter or early spring; light pruning can be done as needed throughout the growing season.
- 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 (6–8 hours of direct sunlight daily); tolerates partial shade but may produce fewer flowers.
Sunlight Tolerance Tips:
Acclimate plants gradually if moving from shade to sun; protect from intense midday sun in hot climates; ensure good air circulation to prevent mildew in humid conditions.
Care Requirements
Care Difficulty
easymoderate
Sunlight
full sun
Rotate plants for even growth; use shade cloth in extreme heat; avoid placing in drafty areas.
Watering
every 7–10 days during active growth, reduce in winter
Water thoroughly until runoff; allow soil to dry between waterings; avoid overhead watering to prevent fungal issues.
Soil
well-drained, fertile loam
pH: Slightly acidic to neutral (pH 6.0–7.0).
Test soil pH annually; amend with organic matter; ensure good drainage; avoid compacted soil.
Temperature
Thrives in warm conditions (65–85°F or 18–29°C); prefers tropical or subtropical climates; sensitive to frost.
Avoid sudden temperature changes; protect from frost; ensure good air circulation in hot weather.
Fertilizing
every 4–6 weeks during growing season
Avoid over-fertilizing to prevent root burn; fertilize after watering to prevent salt buildup; use organic options like compost for slow release.
Propagation
Methods
Stem cuttings or division; seeds can also be used but may take longer to establish.
Step-by-Step Propagation Guide
- Take 4–6 inch cuttings.
- Remove lower leaves.
- Dip in rooting hormone (optional).
- Plant in medium.
- Maintain humidity.
Best Time: Spring or early summer when the plant is actively growing.
Environment
Warm, humid environment with indirect light; keep soil consistently moist but not waterlogged.
Medium
Well-draining mix like perlite and peat moss; can also root in water initially.
Hormone
Rooting hormone can be used but is not strictly necessary for Tithonia.
Timeline
Roots may form in 2–4 weeks; establish in new pot within 1–2 months.
Tools Needed
Pruning shears, rooting hormone, small pots, well-draining medium.
Quick Tips
Use healthy, non-flowering stems; maintain high humidity with a plastic bag; avoid direct sun during rooting.
Pruning & Repotting
Pruning Guide
Method
Use clean cuts just above a leaf node or branch junction; remove crossing or crowded branches to improve air circulation.
Pruning Plan
Prune to control size, encourage bushier growth, and remove dead or diseased parts; focus on shaping during active growth.
Tools
Pruning shears, loppers (for larger stems), disinfectant for tools.
Checklist
Disinfect tools; prune during dormancy or active growth; remove dead/diseased parts; shape as desired.
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
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 container; beneficial for container-grown plants to refresh soil and space.
Checklist
Choose appropriate pot size; prepare fresh soil mix; handle roots carefully; water after repotting; place in appropriate light.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture before watering; water deeply; ensure proper drainage; adjust frequency seasonally.
How to Apply Water Properly
Water at the base of the plant, focusing on the root zone; ensure water penetrates deeply to encourage deep roots; water early in the morning to minimize evaporation and fungal growth.
Watering Schedule Tips
Water deeply once a week during active growth; reduce frequency in winter or drought; adjust based on rainfall and soil moisture.
Soil Improvement
Add compost or well-rotted manure to enhance fertility; incorporate perlite or sand for drainage; mulch to retain moisture and suppress weeds.
Temperature Stress Management
Signs of Temperature Issues
Chlorosis or wilting in extreme heat; stunted growth or leaf drop in cold stress; blackened stems in frost damage.
Cold Stress
Low temperatures slow growth and can cause leaf drop; prolonged cold may lead to root damage or death.
Solution: Protect with frost cloth or mulch in cold spells; move potted plants indoors; avoid overwatering in cold conditions.
Hot Stress
Excessive heat can cause wilting, flower drop, or leaf scorch; may go dormant in extreme heat.
Solution: Provide afternoon shade; water deeply and mulch to retain moisture; increase humidity around the plant if possible.
Fertilizing Guide
Fertilizing Checklist
Check fertilizer type; follow dilution instructions; apply during active growth; avoid contact with leaves.
Fertilizing Method
Use balanced, slow-release fertilizer in spring; apply liquid fertilizer monthly during growing season; reduce or stop in winter.
Common Problems & Solutions
Toxicity Warning
Cats
Non-toxicTithonia diversifolia is not known to be toxic to cats. There are no reported adverse effects from ingestion or contact with this plant.
⚡ Toxic If:
None
Dogs
Non-toxicTithonia diversifolia is not known to be toxic to dogs. There are no reported adverse effects from ingestion or contact with this plant.
⚡ Toxic If:
None
Humans
Non-toxicTithonia diversifolia is not known to exhibit toxic effects in humans under normal conditions. It is generally considered safe for handling and consumption.
⚡ Toxic If:
None
Frequently Asked Questions
Q: Is Tithonia diversifolia invasive?
A: It can be invasive in some regions, particularly in tropical and subtropical areas, where it may outcompete native vegetation.
Q: How tall does Tithonia diversifolia grow?
A: It can grow up to 10 feet tall, sometimes reaching 20 feet under ideal conditions.
Q: Does Tithonia diversifolia attract pollinators?
A: Yes, it is highly attractive to bees, butterflies, and other pollinators due to its bright flowers.
Quick Reference
| Family: | Asteraceae |
| Care: | easy |
| Light: | full sun |
| Water: | every 7–10 days during activ |
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