Genus Ageratum (Floss flower)

Ageratum houstonianum

a-jer-AY-tum Common Name: Floss flower

Plants in the genus Ageratum include 40 or so species of annuals, perennials, and shrubs from North and South America. Most are grown as annuals in the garden, and most form dozens of small flowerheads in the form of soft, rounded clusters in summer and fall. They are good choices for edging, bedding, or containers.
Noteworthy characteristics: Clusters of 30 to 50 small flowerheads. Attractive to butterflies. Usually grown as annuals.
Care: Provide full sun to part shade. Soil should be fertile and moist but well-drained.
Propagation: In early spring, sow seed at 61° to 64°F. Or, sow in autumn and overwinter at 50°F.
Problems: Southern blight, crown rot, root rot. During cool, wet weather Botrytis blight may affect plants, while rust and powdery mildew can be problems in dry summers.

Species, varieties and cultivars for genus Ageratum

Ageratum houstonianum
(1 user review)

Hardiness Zones:

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There are many cultivars available of this fast-growing annual. They are best used as bedding, edging, or container plants. Panicles of blue, pink, purple, or white flowerheads arise from oval, downy leaves in midsummer and continue until frost. They have a soft, fuzzy appearance and attract butterflies.

Ageratum houstonianum 'Blue Danube'
('Blue Danube' ageratum, 'Blue Danube' floss flower) Be the first to rate this plant

This early, compact bloomer grows to only about 6 or 7 inches tall. With its icy blue-purple flowers, it works well when planted tightly along the foreground of a bed. Its color blends easily with most other hues and textures. -Julia Jones, Designing with annueals, Fine Gardening issue #120

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