Common Name Floss Flower, Bluemink, Blueweed
Genus  Ageratum
Species A. houstonianum
Family Asteraceae
Life Cycle  Tender Annual 
Tray Size  210
Plug Care Plant or bump up to larger pots shortly after receiving plugs. If flowering prematurely, just pinch off flowers to promote side branching and longer stems. Initially, keep the plants well watered after transplant, and then water  only as needed. 
Netting / Staking Helpful in windy areas, but not necessary. 
Temperature Range Will not tolerate frost, so plant after all threat of frost has  passed. Ideal temperature is 60-70F. 
Spacing Generally 9-12" will work - for flowers all season (cut and come again) use 12", for succession plantings that are to be composted after a couple harvests, plant more densely. 
Soil Preference Fertile, well drained soil. Performs best with neutral to  acidic pH (5.5-6.5). 
Day Length Facultative long-day. Plant in full sun. Temperature is more important than photoperiod for winter growing. 
Pinching Helpful to promote early branching, but not necessary. 
When to Plant Plant in the spring after threat of frost has passed. Succession sow 2-3 times, about two weeks apart in the spring and early summer for flowers right through to frost. 
Harvesting Expect the first flowers approximately 3-5 weeks after  transplanting depending on weather and temperature.  Harvest when flowers are fully open. If harvested in bud, stems are likely to wilt.
Post Harvest Care Expect a vase life of 7-10 days. Floral  conditioner/preservative will help increase vase life. Can be stored for a short period in a cooler if not needed immediately. 
Diseases / Insects Relatively disease and pest free. Can succumb to powdery mildew, aphids,  thrips or spider mites if stressed. 
Bailey's Notes Deadhead to prolong blooming window. Fertilize with a well balanced calcium-nitrate based formulation to build  healthy plants. Avoid excess nitrogen which will cause  excessive foliage growth, invite disease and decrease vase life. 

Ageratum Blue Horizon Culture Sheet

Ageratum Blue Planet Culture Sheet