annualN. America Native

Spanish Needles

Bidens bipinnata

The Story

Plant Bio

Bidens bipinnata, commonly known as Spanish needles, is an erect, branching annual herb native to eastern and central North America. It features deeply divided, fern-like dark green foliage and produces small, yellow flower heads throughout summer and fall.

The species is distinguished by its highly dissected, bipinnate leaves and its narrow, barbed seeds that cling tenaciously to passing animals and clothing. While serving as a native wildflower, its aggressive self-seeding habit often causes it to behave as a weed in disturbed garden soils.

Uses & Benefits:

Offers a wild, naturalistic appearance with delicate, fern-like foliage and small yellow flowers.

Serves as an adaptable, drought-tolerant ground cover for poor, rocky soils where other plants struggle.

Provides nectar and pollen for native bees, beneficial insects, and generalist pollinators.

Essentials

At a Glance

Plant Type

Annual

Height

60"

Width

24"

Light

Full Sun, Partial Sun

Zones

4, 5, 6, 7, 8, 9, 10

Water

Low to Moderate

Humidity

High

Lifespan

Annual

Native To

North America

Toxicity

Minor Contact Irritant / Ingestion Hazard

Bloom period

Summer – Fall

In flower about 6 months of the year

Planting

How to Grow

Sow seeds directly into well-drained soil in spring once the threat of hard frost has passed.
Select a site in full sun to partial shade with sandy, loamy, or rocky soil.
Water moderately during establishment, then reduce frequency as the plant develops high drought tolerance.
Deadhead the spent yellow flowers continuously if you wish to prevent the aggressive spread of the barbed seeds.

Pro Tip

Withhold all supplemental fertilizer to maintain a sturdy, upright form; excess nutrients cause the stems to become weak and floppy, requiring artificial staking.

Keep It Thriving

Care Guide

Do

Grow in poor, well-drained soils to encourage compact, self-supporting growth.
Wear gloves when handling the foliage to avoid potential skin irritation.
Allow the plant to complete its annual cycle if naturalized self-seeding is desired.

Don't

Do not apply nitrogen-rich fertilizers, which trigger weak, floppy stems.
Do not plant in poorly drained or waterlogged soils where root rot can develop.
Do not allow the seed heads to mature near paths or pet runs where the barbed awns will cling to fur and clothing.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Deadhead
Pest Check
Plant
Spring Cleanup

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Wildflower MeadowsNaturalized AreasPollinator Gardens

Companion Plants

Coreopsis lanceolata Symphyotrichum novae-angliae Rudbeckia hirta

Multiply

Propagation Methods

Good to Know

Common Questions

Spanish Needles questions

What zones can Spanish Needles grow in?

Spanish Needles is hardy in USDA Zones 4–10. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Spanish Needles deer resistant?

Not reliably. Deer may browse Spanish Needles, especially tender spring growth — plan on repellents or fencing where pressure is high.

When does Spanish Needles bloom?

Spanish Needles typically blooms in summer through fall. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Spanish Needles need full sun?

Spanish Needles does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.

Is Spanish Needles drought tolerant?

Yes — once established (usually after the first full season), Spanish Needles handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.