Ageratum Houstonianum, commonly know as Floss Flower Bluemink, Blueweed, Pussy Foot or Mexican Paintbrush, is a member of the Aster family that includes 40 species of annuals, perennials and shrubs.
Ageratum is grown for its fluffy pompom-shaped flowers that occur mostly in shades of blue, although colours also include white, pink, lavender, and red, attractive to butterflies, hummingbirds, and insect pollinators.
The colour blue is a rarity in the gardening world and Ageratum is highly coveted by avid gardeners.
These popular bedding plants are most often purchased as nursery tray packs, but can also be grown from seed with variety sizes ranging from a few inches to three feet tall.
A versatile plant, that can be grown in containers, used as edging along pathways or borders, or massed in displays.
You can plant Nursery tray packs outdoors, from late spring to early summer.
Sow seed indoors, 8 to 10 weeks, before your last average frost date, or seeds can be sown directly outdoors after any threat of frost; however, these plants will not bloom until late summer or autumn, as Ageratums are heat lovers and will fail to thrive if it’s too cold.
Plant in a border or in containers, in rich, well draining soil that will stay moist. Dead-head regularly to encourage new flowers. Cut back any plants that start to look tired or are outgrowing their space. They should re-bloom again within a week or two.
Ageratums are greedy feeders and benefit from regular fertilising. Mix a slow-release fertiliser into the soil at the time of planting and re-apply mid-season, or use a water-soluble fertiliser twice a month. Yellow leaves could be a sign that plants aren’t receiving enough fertiliser.
They have shallow roots, so can quickly dry out and wilt, water at least weekly, or more as needed during warm spells.
To prevent foliar diseases, water at the base of the plants, rather than overhead.
The plant is poisonous, if ingested, so site ageratum carefully if you have small children and pets around.