How to Grow Bur-marigold
Wikimedia Commons
Bur-marigold
Bidens pilosa
flowerBur-marigold is a fast-growing annual flowering plant native to tropical regions, characterized by small yellow flowers and distinctive barbed seeds that cling to clothing and animal fur. It thrives in warm conditions and is known for its prolific self-seeding and resilience in poor soils. The plant has both ornamental value and traditional medicinal uses across many cultures.
When should you plant Bur-marigold in your zone?
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Example Bur-marigold timeline · Pittsburgh, PA (Zone 6b)
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Plant Bur-marigold
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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First Bur-marigold blooms
Around Jun 1≈ 45 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Bur-marigold dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 9-12; grown as an annual in cooler zones
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Seedling
2-3 weeksDelicate seedlings with cotyledons and initial true leaves emerge within 7-10 days
Keep soil lightly moist; provide bright light; thin seedlings to proper spacing once established
Vegetative
3-4 weeksPlant develops bushy foliage with lance-shaped, finely divided green leaves on branching stems
Water moderately; pinch back stems to encourage bushiness; minimal feeding required
Flowering
4-8 weeks (or longer with deadheading)Small, cheerful bright yellow flowers appear in clusters at branch tips and leaf axils
Deadhead spent flowers to encourage continuous blooming; ensure good air circulation
Seed Development
2-3 weeksFlowers fade and develop distinctive barbed, needle-like seeds (achenes) that readily attach to fabric and fur
Allow some flowers to mature for seed collection; manage self-seeding if needed to prevent volunteer plants
Harvest/End of Season
Varies by climatePlant gradually declines in frost-prone areas or can persist through warm seasons in tropical climates
Cut back or remove spent plants; collect seeds if desired for next season; compost plant material
Common Pests
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Spray with neem oil or insecticidal soap; encourage beneficial insects like ladybugs
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Increase humidity; spray with water to dislodge; use miticide if severe
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Yellow sticky traps; neem oil spray; reflective mulches
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Improve air circulation; remove affected leaves; apply sulfur dust or baking soda spray
Uses
Traditional herbal remedy
MedicinalBur-marigold has been used in Ayurvedic, Traditional Chinese Medicine, and Latin American herbalism to support immune function, digestion, and inflammation management. Various parts of the plant including leaves and roots are brewed into teas or herbal preparations. [source]
Edible greens and tea
CulinaryYoung leaves can be eaten raw in salads or cooked as greens in some cultures. Dried leaves and flowers are brewed into herbal tea with a slightly bitter, pleasant flavor. [source]
Bright garden color
OrnamentalCheerful yellow flowers brighten borders, beds, and containers, attracting pollinators and bringing extended color to gardens in warm climates. [source]
Pollinator support
WildlifeSmall flowers attract bees, butterflies, and other beneficial insects throughout the blooming season, supporting pollinator populations. [source]
Seed dispersal interest
HouseholdThe distinctive barbed seeds naturally adhere to clothing and fur, making them an interesting teaching tool for understanding plant reproduction and ecological adaptation. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
For ornamental use, cut flowers in the morning when blooms are fully open. For seeds, allow flowers to mature on the plant and collect the barbed seeds when brown and dry, or allow them to self-scatter. Wear gloves when handling mature seed heads to avoid skin irritation from the barbs.
Fun Facts
- 🌱 The barbed seeds are a marvel of natural engineering—they effortlessly attach to clothing, animal fur, and socks, which is why this plant has become established on every continent except Antarctica.
- 🌱 In Spanish-speaking countries, bur-marigold is called 'romerillo' or 'amor seco' (dry love), and it has a long history in traditional medicine spanning from Mexico to South America to the Caribbean.
- 🌱 Despite being considered a weed in some regions, modern scientific research has confirmed many of the traditional medicinal uses, with studies examining compounds like flavonoids and polyphenols in the plant.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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