Ageratum (Floss flower) Growing guide Ageratums are amongst the few blue flowered annuals, their main feature is the clusters of fluffy flowers which also come in pinks, reddish purple tones and white. The shorter varieties, at 6-8in/15-20cm are excellent edging plants and long flowering mixers for containers while the few taller varieties at about 2-21/2ft/60-75cm are valuable in mixed borders and for cutting. Type Half hardy annual. Garden conditions Ageratums enjoy sunny situations and any reasonably fertile soil which does not dry out. They will take a little shade but in full shade become sparse, leggy and flower poorly. Sowing indoors Sow the seed in early spring at about 70F/21C in any fresh seed mixture. Press the seed into the seed compost then leave it uncovered - but it's important to be sure that the seed does not dry out. Covering with clear film allows light in and at the same time retains moisture. Pricking out Prick out as soon as the seedlings are large enough to handle into 2in/5cm pots or into seed trays. Dwarf varieties can grow on in these containers until planting time, taller varieties are best moved on into 31/2in/9cm pots. Growing on Keep growing and in good light, ageratums appreciate feeding regularly with liquid feed. Planting out Plant out in early summer, after the last frost in your area. Sowing outdoors Ageratums are generally unsuitable for sowing outdoors. Pests and diseases Greenfly and other aphids are the most common problem; the flowers may rot in long wet spells or warm weather.   Ageratum 'Blue Mist' Variety guide 'Bavaria' Unique blue and white bicolour; superb. 8-12in/20-30cm. 'Blue Danube' Soft powder blue; neat. 6in/15cm 'Blue Horizon' Purplish blue, great for cutting. 21/2ft/75cm 'Blue Mink' Old favourite, azure blue. 8in/20cm 'Blue Mist' Excellent bright blue; rounded habit. 6in/15cm 'Pinky Improved' The best pink. 6in/15cm 'Red Sea' Good cut flower type in purplish red. 21/2ft/75cm 'Southern Cross' Same as 'Bavaria'. 'Summer Snow' The best white, but the flowers age to a dirty brown. 6-8in/15-20cm 'Swing' Dwarf mixture or blue, pink and white. 6-8in/15-20cm 'White Bouquet' Lovely tall white for borders or cutting. 21/2ft/75cm Back to Annuals A-Z     ©copyright 1999 Graham Rice. All Rights Reserved. All Images Digitally Watermarked.