Ageratum houstonianum is a cool-season annual plant that is native to Central America and adjacent parts of Mexico. Its common names include floss flower, bluemink, blueweed and Mexican paintbrush. There are many cultivars available of this fast-growing annual. The flower heads are borne in dense corymbs. The ray flowers are threadlike, leading to the common name.
Cultivar “Hawaii Blue 5.0”
An improvement of the market leading Hawaii Blue, the new genetics of Blue Hawaii 5.0 Ageratum delivers a compact habit, early flowering, and excellent performance in pack, pot, and garden.
In the Garden
They are best used as bedding, edging, or container plants. Works very well along walkways and edges of beds. Panicles of blue, pink, purple, or white flowerheads arise from oval, downy leaves in midsummer and continue until frost.
- Grows up to 5-6″ tall, but spreads gracefully to about 9-10″ wide.
- Showy flowers that attract butterflies.
Caring & Growing
Easily grown in average, moist, well-drained soils in full sun.
Grow at 64 to 68 degrees. Temperatures below 64 degrees delay flowering.
Tolerates light shade, and prefers some light afternoon shade in hot summer climates.
Prefers rich soils with good drainage and consistent moisture throughout the growing season. Plants tend to wilt quickly if soils are allowed to dry out.
Water regularly until the plant is established.
Moderate fertilization using a complete balanced fertilizer. Avoid high ammonium and high nitrogen levels.
Prompt deadheading of the faded flowers is not necessary, but keeps a planting tidy and tends to promote a better uninterrupted bloom.
In climates where powdery mildew is a problem, avoid overhead watering and site in areas with good air circulation.