Ageratum houstonianum ‘Blue Horizon’
Overview
Uses: Annual borders, cutting gardens, pollinator plantings, mixed containers, mid-border accents
Benefits: Tall stems with soft, fluffy lavender-blue flower clusters, extended bloom season, strong cut-flower performance, reliable summer color
USDA Hardiness Zones: Annual
Sun: Full Sun to Partial Shade
Life Cycle: Annual
Growth Habit: Upright, Mounding — branching stems with rounded form
Bloom Color: Lavender to Blue
Mature Height: 24–30 inches
Mature Width: 12–18 inches
Bloom Season: Late Spring through Frost
Growth Rate: Fast
Summary
‘Blue Horizon’ delivers tall stems topped with soft, cloud-like clusters of lavender-blue blooms that bring consistent color from late spring until frost. Its height sets it apart from compact ageratum varieties, making it especially useful in cutting gardens and the middle of sunny borders.
The airy flower clusters resemble small asters and attract bees and butterflies throughout the growing season. Strong stems support the blooms well, even during summer heat.
This variety forms a tidy, rounded mound and pairs easily with zinnias, salvia, and other warm-season annuals for layered seasonal displays.
Care
Ageratum Care
Plant after the danger of frost has passed and when soil temperatures have warmed. Provide full sun for best flowering, though light afternoon shade can be beneficial in hotter regions.
Grow in well-drained soil and water regularly during establishment. Once established, maintain consistent moisture without allowing soil to remain saturated.
Apply a balanced slow release fertilizer at planting to support steady growth and flowering.
Deadheading spent blooms can encourage continued flowering and help maintain a tidy appearance.
Container Growing
‘Blue Horizon’ performs well in large patio containers with adequate drainage. Container-grown plants will require more frequent watering, particularly during periods of summer heat.
Use quality potting mix and fertilize consistently, as nutrients leach more quickly from containers.
Plants hardy in the ground may require winter protection when grown in containers in colder zones.
Size
What Size is the Ageratum ‘Blue Horizon’ for Sale Online?
Plants ship in a greenhouse-grade grow pot and are actively growing at the time of shipment. Each plant is well-rooted and appropriately sized for its container. If you have specific sizing questions, please contact us for additional details.
How Large Does Ageratum ‘Blue Horizon’ Grow?
Mature plants typically reach 24–30 inches tall and spread 12–18 inches wide, forming a rounded mound with upright flowering stems.
Additional Information
What are some common names for this plant?
This plant is commonly known as Floss Flower.
How is ‘Blue Horizon’ different from other ageratums?
Unlike compact bedding ageratum varieties, ‘Blue Horizon’ grows taller and produces longer stems, making it particularly useful for cut flower arrangements and mid-border placement.
Where can I find more plants that pair well with ageratum?
Explore our collections of Annuals and Zinnias to create vibrant seasonal combinations.
Is this plant attractive to pollinators?
Yes. The nectar-rich flowers attract bees and butterflies throughout the summer growing season.
