Swamp Sunflower
helianthus angustifolius
Also known as: ["Narrowleaf Sunflower","Swamp Sunflower"]
Overview
A perennial wildflower native to North America, known for its narrow leaves and bright yellow flowers that bloom in late summer to fall.
Benefits & Perks
["long-flowering","wildlife attractant (bees, butterflies, birds)","drought tolerant","aesthetic foliage"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Asterales |
| Family: | Asteraceae |
| Genus: | Helianthus |
| Botanical Name: | Helianthus angustifolius |
Plant Characteristics
Basic Information
- Category: Flowers
- Suitable Location: garden bed in full sun, or container with adequate space
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"5–35°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 organic matter; can tolerate poor soils but thrives with amendments.
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: moderate
- Pruning Frequency: Annually in late winter or early spring; light pruning can be done after flowering.
- Pruning Intensity: Moderate; remove up to one-third of the plant for rejuvenation.
Care Details
Ideal Sunlight Coverage:
Full sun (6–8 hours/day) is ideal; adjust for intense summer sun by providing partial afternoon shade.
Sunlight Tolerance Tips:
Acclimate plants gradually to intense sunlight; protect from scorching by providing shade during peak heat; adjust placement based on indoor/outdoor conditions.
Care Requirements
Care Difficulty
easymoderate
Sunlight
full sun
Rotate plants for even light exposure; use sheer curtains to filter intense sun; monitor for sunburn signs.
Watering
every 7–10 days during active growth, less frequently in dormant periods
Water at the base to avoid foliage wetting; ensure soil dries slightly between waterings; avoid overwatering to prevent root rot.
Soil
well-draining, moderately fertile soil
pH: Slightly acidic to neutral (pH 6.0–7.0).
Test soil pH annually; amend with organic matter; ensure proper drainage to avoid root rot.
Temperature
Prefers 65–85°F (18–29°C); tolerates heat but may require shade in extreme conditions.
Monitor temperature extremes; adjust care seasonally; protect from frost or heatwaves.
Fertilizing
every 4–6 weeks during growing season, none in winter
Apply fertilizer after watering; stop feeding in late fall; use organic options for slow release.
Propagation
Methods
Stem cuttings or division; stem cuttings are more common for home growers.
Step-by-Step Propagation Guide
- Take 4–6 inch cuttings.
- Remove lower leaves.
- Dip in rooting hormone.
- Plant in medium.
- Maintain humidity.
Best Time: Spring or early summer when the plant is actively growing.
Environment
High humidity (70–80%), warm temperatures (70–75°F), and indirect light.
Medium
Well-draining mix of perlite and peat moss or cactus mix.
Hormone
Rooting hormone is recommended to speed up root development.
Timeline
Roots develop in 2–4 weeks; establish in new pot within 2–3 months.
Tools Needed
Pruning shears, rooting hormone, small pots, misting spray bottle
Quick Tips
Use healthy, non-flowering stems; maintain consistent moisture; provide bottom heat for faster rooting.
Pruning & Repotting
Pruning Guide
Method
Cut stems just above a leaf node or bud; thin out crowded growth to improve air circulation.
Pruning Plan
Prune to maintain shape, encourage bushier growth, and remove dead or diseased stems.
Tools
Pruning shears, sharp knife, gloves
Checklist
Sterilize tools; prune dead/damaged stems; shape the plant; clean up debris
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.
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 outgrow the container; beneficial for container-grown plants.
Checklist
Choose appropriate pot; prepare new soil mix; handle roots carefully; 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 thoroughly until it drains from the bottom, ensuring the root zone is saturated. Water early in the morning to minimize evaporation and fungal issues.
Watering Schedule Tips
Water deeply once a week during active growth, reducing frequency in winter. Adjust based on rainfall and soil moisture retention.
Soil Improvement
Add compost or well-rotted manure; incorporate perlite or sand for drainage; use mulch to retain moisture.
Temperature Stress Management
Signs of Temperature Issues
Wilting, leaf scorch, stunted growth, or bud drop indicate temperature stress.
Cold Stress
Low temperatures slow growth and may cause leaf damage or dieback in frost.
Solution: Provide frost protection with row covers; move potted plants indoors; avoid planting in frost-prone areas.
Hot Stress
Excessive heat can lead to wilting, leaf drop, and reduced flowering.
Solution: Provide afternoon shade; increase watering; use mulch to retain soil moisture.
Fertilizing Guide
Fertilizing Checklist
Check fertilizer type; dilute properly; apply during active growth; avoid winter feeding
Fertilizing Method
Use balanced liquid fertilizer diluted to half strength every 4–6 weeks during growing season; avoid fertilizing in winter.
Common Problems & Solutions
Toxicity Warning
Cats
Non-toxicHelianthus angustifolius is not considered toxic to cats. The plant does not produce compounds that are harmful to felines.
⚡ Toxic If:
Generally not toxic
Dogs
Non-toxicHelianthus angustifolius is not considered toxic to dogs. The plant does not produce compounds that are harmful to canines.
⚡ Toxic If:
Generally not toxic
Humans
Non-toxicHelianthus angustifolius, commonly known as narrowleaf sunflower, is not considered toxic to humans. It is a plant species that is generally safe for human contact and consumption.
⚡ Toxic If:
Generally not toxic
Frequently Asked Questions
Q: How tall does Swamp Sunflower grow?
A: It typically grows to 4-6 feet tall.
Q: Does it require full sun?
A: Yes, it thrives in full sun but can tolerate partial shade.
Q: Is it suitable for wet soil?
A: Yes, it is adapted to moist to wet soil conditions.
Quick Reference
| Family: | Asteraceae |
| Care: | easy |
| Light: | full sun |
| Water: | every 7–10 days during activ |
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