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Broom Cupflower (Nierembergia scoparia), whole plant
  • Broom Cupflower — close-up of leaves and flowers
  • Broom Cupflower — seasonal appearance
  • Broom Cupflower in a garden setting

Broom Cupflower

Nierembergia scoparia

Easy · Beginner friendly

About Broom Cupflower

Cupflower is an Argentine tender perennial grown as an annual in American gardens, forming low mounds covered in 1-inch cup-shaped flowers in violet-blue or white with yellow throats. Growing 6 to 10 inches tall and spreading 12 inches, it blooms continuously from spring through frost and tolerates heat, making it popular for edging, rock gardens, and containers. 'Mont Blanc' and 'Purple Robe' are the iconic AAS cultivars.

  • Heat-tolerant
  • Container-friendly
  • Long-blooming
  • Pollinator-friendly
WATER
Regular
Top inch dry
LIGHT
Full sun
6+ hrs direct
HARDY
Hardy to 0°F (-18°C)
USDA hardiness zones 7–10

How to care for Broom Cupflower

Watering

  • Springevery 5 days
  • Summerevery 4 days
  • Fallevery 7 days
  • Winterevery 10 days

Soil · Well-draining

  • Top dressingPine bark mulch10%
  • Main mixPotting soil + perlite 2:170%
  • DrainageLECA / gravel20%

Never skip the drainage layer — standing water is the top cause of root rot.

FERTILIZER

Balanced Feed 14-14-14

An even feed covers all three needs at once, keeping leaves, roots and blooms moving together with nothing pushed out of balance.

N33%P33%K33%
  • Nitrogen · Leaves
  • Phosphorus · Roots + Blooms
  • Potassium · Strength
  • Springevery 30 days
  • Summerevery 30 days
Get watering reminders for Broom Cupflower — free on iPhoneDownload on the App Store

At a Glance

  • NativeSouth America
  • Height0.5–1 ft (0.2–0.3 m)
  • Spread1–1.5 ft (0.3–0.5 m)
  • Flower colorPurple, White
  • Foliage colorGreen
  • SoilWell-drained, Loamy
  • LocationsYard · Balcony

Bloom time

BLOOM CYCLE

Peak bloom

Mar–Nov

J
F
M
A
M
J
J
A
S
O
N
D

Cup-shaped blue or white flowers spring to frost

Toxicity

Toxicity unknown

None reported

Unknown

EXPOSURE Unspecified plant material.

EFFECT Toxic effects are not specified.

NOTE Toxicity for humans is not well documented; use caution until verified.

Unknown

EXPOSURE Unspecified plant material.

EFFECT Toxic effects are not specified.

NOTE Toxicity for dogs is not well documented; use caution until verified.

Unknown

EXPOSURE Unspecified plant material.

EFFECT Toxic effects are not specified.

NOTE Toxicity for cats is not well documented; use caution until verified.

Educational information, not medical or veterinary advice. If exposure is suspected, contact a doctor or veterinarian.

DISTRIBUTION

Broom Cupflower · Native
  • Native
  • Introduced
  • South America

History

Illustrated historical scene for Broom Cupflower

Nierembergia scoparia, sometimes sold under the older name N. hippomanica var. violacea, is a low-growing short-lived perennial native to Argentina and Uruguay. French botanists Sendtner and Grisebach worked out the modern taxonomy in the 19th century, and the genus honors Juan Eusebio Nieremberg, a 17th-century Spanish Jesuit naturalist and philosopher. The plant produces fine needle-like foliage covered continuously through spring and summer by small flat-faced cup-shaped flowers in violet-purple or white with contrasting yellow throats.

Breeders at Sakata, Pan American Seed, and Proven Winners have released improved compact selections such as Mont Blanc, Purple Robe, Augusta Blue Sky, and Augusta Blue Skies. In USDA zones 7 and above it often overwinters as a short-lived perennial; elsewhere it is used as a heat-tolerant summer annual.

Native to Argentina, introduced to American gardens in the early 1900s. The AAS-winning 'Purple Robe' (1942) and 'Mont Blanc' (1993) established it as a reliable cool-blue edging annual now found in spring seedling trays across the US.

Symbolism & meaning

What It Symbolizes

Broom Cupflower offers serene constancy, its low mounding habit covered in cool blue-violet cups through long stretches of summer. The color carries calm — a soothing tone that makes hot afternoons feel a degree gentler. As an edging plant of quiet grace, it asks little and contributes a steady, contemplative note where bolder flowers might shout. Its meaning is the comfort of soft, faithful color.

  • Cool calm — soothing blue-violet tones
  • Quiet grace — low mounding edging plant

Where the Name Comes From

'Nierembergia' honors Spanish Jesuit naturalist Juan Eusebio Nieremberg (1595-1658); 'scoparia' means broom-like, for growth habit.

Uses & Fun Facts

  • Cup-shaped flowers attract bees through long summer bloom
  • Compact mounding annual fills patio pots and edging

Related plants

Plants with similar care

Frequently asked questions

How often should I water Broom Cupflower?

In summer, water about every 4 days; in winter, about every 10 days. Adjust for heat, pot size and drainage.

How much light does Broom Cupflower need?

Full sun: 6+ hrs direct. Watch the leaves — scorching or stretching means the light needs adjusting.

Is Broom Cupflower toxic to cats or dogs?

Pets Unknown (Dogs Unknown · Cats Unknown) Educational information, not medical or veterinary advice. If exposure is suspected, contact a doctor or veterinarian.

Is Broom Cupflower easy to grow?

Yes — it is considered an easy, beginner-friendly plant.

When does Broom Cupflower bloom?

It typically blooms Mar–Nov in the Northern Hemisphere.

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