Floss Flower (Ageratum houstonianum)-Hort Answers - University of Illinois Extension
University of Illinois Extension

University of Illinois Extension

Hort Answers

Annual

Floss Flower
Ageratum houstonianum

 
Features

Excellent low growing, mound plant useful for borders while the taller cultivars make excellent cut flowers.

 
 
Culture
Prefers full sun, but tolerates very light shade. Likes soil that is moist yet well-drained. Plant after all danger of frost is past. Needs fertile soils to continue to bloom through the summer. Removing spent flowers aids in rebloom and disease reduction. 
 
Cultivars
  • 'Artist' series hybrids 12"-14" blue and purple flowers
  • 'Blue Hawaii 5.0' 6"-12" blue flowers
  • 'Blue Danube'
  • 'Blue Pearl'
  • 'Shell Pink Hawaii'
  • 'Tycoon'

Tall Cut Flower Types

  • 'Blue Horizon' 24"-36" mid-blue flowers
  • 'Everest Blue'
  • 'Fields'
  • 'High Tide Blue'
  • 'Red Sea' 24" -36" red flowers
 
 
Mature Height
6-36 Inches
 
Size
Small
Medium
Tall
 
 
Annual Hardiness Type
Tender Annual
 
 
Bloom Color
Blue
Pink
Purple
White
 
 
Bloom Season
May - October
 
Soil Conditions
Dry
 
 
Exposure/Light Requirements
Full Sun
 
 
Pests and Problems

Environmental Damage

Fungal Disease

Herbicide Injury


Additional pests and problems that may affect this plant:

None that are destructive. Powdery mildew, botrytis, root rots.

Mulching too close to the stem can cause crown rots to develop.

Needs good air circulation to prevent fungal disease problems

 
Additional Notes
Great plant for interplanting with light colored or silvery colored foliage plants or with white petunias

 

 
Related Resources
Home, Yard & Garden Pest Guide
Illinois Commercial Landscape and Turfgrass Pest Management Handbook
U of IL - Distance Diagnosis through Digital Imaging
U of IL - Plant Clinic