Ageratum houstonianum 'Red Flint'
Overview
Uses: Annual borders, cottage gardens, containers, pollinator beds, and cut-flower gardens.
Benefits: Unique ruby-red to magenta blooms on compact, bushy plants. Long-lasting color, soft fuzzy flower clusters, and excellent performance in warm summer weather. A pollinator favorite!
USDA Hardiness Zones: 10 – 12 (grown as an annual in colder zones)
Life Cycle: Tender perennial (grown as a warm-season annual outside Zones 10–12)
Sun: Full Sun to Partial Sun
Mature Height: 10" – 14"
Mature Width: 10" – 12"
Bloom Season: Early Summer through Frost
Growth Rate: Moderate
Summary
Ageratum houstonianum ‘Red Flint’ is an uncommon and dazzling selection of Flossflower, prized for its soft, ruby-red blooms that shimmer with hints of rose and magenta. The dense clusters of fuzzy, button-like flowers appear continuously through the summer, creating a striking contrast against lush green foliage.
Unlike many Ageratum varieties that lean toward blues and purples, ‘Red Flint’ stands out for its warm tone—perfect for pairing with yellow marigolds, orange zinnias, or white alyssum. Compact and mounding, it’s ideal for edging garden beds, filling containers, or massing in seasonal displays.
Butterflies, bees, and hummingbirds can’t resist its nectar-rich blooms, making it as functional as it is beautiful. Easy to grow, non-stop blooming, and low maintenance—‘Red Flint’ brings bold, cheerful energy to every garden space.
Care
Ageratum ‘Red Flint’ Care
Plant outdoors after all danger of frost has passed, or start seeds indoors 6–8 weeks before your last expected frost date. Transplant when nighttime temperatures remain above 55°F.
Grow in full to partial sun and fertile, well-drained soil. Regular watering helps maintain constant blooming, but avoid overwatering—Ageratum dislikes soggy soil. Mulching helps conserve moisture and reduce weeds.
Feed every 4–6 weeks during active growth with a balanced slow release fertilizer to encourage vibrant color and steady flower production.
Deadhead spent blooms regularly to extend the flowering season. Plants may be lightly trimmed midseason to maintain shape and encourage fuller growth.
Size
Size of Ageratum ‘Red Flint’ for Sale Online
Our Ageratum ‘Red Flint’ plants are greenhouse-grown and shipped healthy, ready to thrive in your garden or decorative planters. Each plant arrives in an appropriately sized grow pot. For current sizing and availability, please contact us.
Size of Ageratum ‘Red Flint’ When Fully Grown
Expect mature plants to reach 10"–14" tall and 10"–12" wide, forming compact mounds covered in fuzzy red blooms all summer long.
Additional Information
Is Ageratum ‘Red Flint’ a perennial or annual?
‘Red Flint’ is a tender perennial in Zones 10–12 but is grown as a warm-season annual in most climates due to frost sensitivity.
Does Ageratum attract pollinators?
Yes! Its nectar-rich blooms attract bees, butterflies, and even hummingbirds throughout the growing season.
Can Ageratum be grown in containers?
Absolutely. Compact and tidy, ‘Red Flint’ is perfect for patio pots, window boxes, and mixed container gardens.
Does Ageratum reseed?
In frost-free climates, it may lightly reseed. In cooler zones, treat it as an annual and replant each spring for consistent color.
Is Ageratum toxic?
Ageratum houstonianum may cause mild stomach upset if ingested in large amounts. It’s best to keep plants away from pets that like to chew foliage.
