Alphabetical Plant Listing

Ageratum houstonianum (Floss Flower)

Ageratum, Floss Flower


An old favorite with its fluffy round clusters, Ageratum houstonianum (Floss Flower) is one of the few annuals to tolerate light shade. A nonstop bloomer from mid summer to fall (Ageratum means 'long-lived' in Greek), it grows easily in shapely mounds ranging from 6-24 in. tall (15-60 cm) and mixes extraordinarily well with all other annuals and perennials. Its colors range from blue, purple, lavender to pink, red, white and bicolor, providing a nice contrast with the rest of the bedding plants. It is deer, rabbit resistant and attracts butterflies.

  • Easy to grow, Ageratum houstonianum performs best in full sun in rich soils with good drainage and consistent moisture during the growing season. Don't let it dry out! Avoid overhead watering and provide good air circulation to prevent the plant from powdery mildew. Light shade is tolerated in hot summer areas.
  • Excellent choice for beds, borders, edgings, mass planting, rock gardens or groundcovers. Perfectly suited to mixed containers too. Excellent as cut flowers (on the taller varieties).

Floss Flower, Ageratum houstonianum, Ageratum Blue Horizon, Ageratum Blue Danube

  • Easily grown from seed, starting indoors in late winter and transplanting outdoors after the danger of frost has passed. Alternatively, seeds can be sown in the garden after the last frost date. If you prefer live plants, they are available from many nurseries.
  • Deadhead spent flowers to keep the plant tidy and promote profuse blooming. In warm climates, Ageratum may self-sow.
  • Main cultivars are:
    Hawaii’ Series flowers in shades of blue, white or pink. Very popular series.
    Bavaria’ has white flowers with bright turquoise borders. Up to 1 foot tall.
    Red Top’ has very striking bright magenta flowers on 3-inch heads. Up to 2.5 feet tall.
    'Blue Danube' is a classic hybrid with purple-blue flowers in dense heads. Compact and reliable garden performer. Very free flowering.
    'Blue Horizon' is one of the tallest (up to 18-30 in. or 45-90 cm) with lavender to purplish-blue flowers resembling asters. Great as cut flowers
    Pinky Improved’ has showy flowers that are dark pink in the centers, fading to pale pink at their fringed edges. Compact and showy.
    Southern Cross’ has bicolor flowers are white in the center, gradually turning to cornflower blue near the edge. Compact and showy.

 

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Requirements

Hardiness 2 – 12
Heat Zones 1 – 11
Climate Zones 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
Plant Type Annuals
Plant Family Ageratum - Floss Flowers
Exposure Full Sun, Partial Sun
Season of Interest Summer (Mid,Late)
Fall
Height 6" – 2' (15cm – 60cm)
Spread 6" – 1' (15cm – 30cm)
Spacing 6" – 12" (15cm – 30cm)
Water Needs Average
Maintenance Low
Soil Type Chalk, Clay, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Moist but Well-Drained
Characteristics Cut Flowers, Showy
Tolerance Deer, Rabbit
Attracts Butterflies
Garden Uses Beds and Borders, Edging, Ground Covers, Patio and Containers
Garden Styles City and Courtyard, Gravel and Rock Garden, Informal and Cottage

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*Photo courtesy of TANAKA Juuyoh

While every effort has been made to describe these plants accurately, please keep in mind that height, bloom time, and color may differ in various climates. The description of these plants has been written based on numerous outside resources.


Requirements

Hardiness 2 – 12
Heat Zones 1 – 11
Climate Zones 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
Plant Type Annuals
Plant Family Ageratum - Floss Flowers
Exposure Full Sun, Partial Sun
Season of Interest Summer (Mid,Late)
Fall
Height 6" – 2' (15cm – 60cm)
Spread 6" – 1' (15cm – 30cm)
Spacing 6" – 12" (15cm – 30cm)
Water Needs Average
Maintenance Low
Soil Type Chalk, Clay, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Moist but Well-Drained
Characteristics Cut Flowers, Showy
Tolerance Deer, Rabbit
Attracts Butterflies
Garden Uses Beds and Borders, Edging, Ground Covers, Patio and Containers
Garden Styles City and Courtyard, Gravel and Rock Garden, Informal and Cottage

Great Plant Combination Ideas with Ageratum - Floss Flowers

Guides with Ageratum - Floss Flowers

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