Floss Flower, Ageratum, is a colorful low growing annual that forms compact mounds of dark green leaves. The mounds are covered with pink, white purple, or blue flowers. Ageratum blooms from early summer to the first frost in autumn.
Get to Know Floss Flower
- Plant type: Annual
- Growing zones and range: 2-11
- Hardiness: Tender; tolerates cool to hot weather; killed by frost.
- Height and width: 6 to 10 inches (15-25cm) tall; 6 to 20 inches (15-51cm) wide.
- Flower form: Small head of fuzzy flowers, in wide, flat bunches.
- Bloom time: Summer; anytime in frost-free regions.
- Botanical name: Ageratum houstonianum
- Common name: Flossflower
Where to Plant Floss Flower
- Plant floss flower in full sun. Plant in part shade where summers are hot.
- Ageratum wants well-drained garden soil with a soil pH of 6.5 to 7.5.
- Turn the soil and add aged compost and lightly fertilizer with an all-purpose fertilizer.
- Use ageratum as an edging for flower beds or as an accent in containers or window boxes.
When to Plant Floss Flower
- Start seeds indoors 6 to 8 weeks before the last frost or later. Sow seeds 1/8 inches deep.
- Seeds germinate in 10 to 14 days in soil 65°F (18°C) or warmer.
- Transplant ageratum into the garden after the danger of frost has passed. In Zones 10 and 11 plants can be set outdoors in winter.
- Sow seed outdoors after the last frost. Keep the seedbed evenly moist.
Planting and Spacing Floss Flower
- Set ageratum in the garden as soon as they are large enough to handle.
- Harden off seedlings started indoors in the shade for several days before planting.
- Set plants into an evenly raked garden bed.
- Space plants 8 to 10 inches (20-25cm) apart.
How to Water and Feed Floss Flower
- Keep the soil evenly moist for floss flower. Plants can tolerate wet or dry soil.
- Water at the base of plants to decrease the chance of fungal disease.
- Feed ageratum before they bloom and again in midsummer. Use a slow-release fertilizer.
Floss Flower Care
- Remove spent blooms to keep floss flower blooming over a long season.
- Ageratum often reseeds in warm, moist climates.
- Remove and replace exhausted plants in midsummer if necessary.
- Taller varieties can be used as cut flowers.
Floss Flower Varieties to Grow
- Cultivars include ‘Blue Horizon’, ‘Red Top’, ‘White Bouquet’, ‘Blue Mink’, ‘Hawaii’, ‘Pink Powderpuffs’, and ‘Wonder White’.