Blue Horizon Floss Flower (Ageratum houstonianum 'Blue Horizon')
a-jer-AY-tum hoos-tone-ee-AY-num 'Blue Horizon'

Annual (usually grown as an annual near you) Upright, Well-Branched in the Asteraceae Family
 
Buy Blue Horizon Floss Flower
Size Notes Price Availability
Tray of 10 4" pots Greenhouse $32.25 Likely available
11/1 - 11/8
1/24 - 4/4

A tall, easy-care annual bred specifically for cutting — masses of fluffy powder-blue blooms from late spring straight through frost, beloved by butterflies and migrating monarchs alike.

Pros

  • Long, reliable bloom season from spring to hard frost
  • Excellent cut flower with good vase life
  • Attracts butterflies, including migrating monarchs
  • Easy from seed, fast to flower

Cons

  • Tender annual, killed by first hard frost
  • Can flop without support in rich soil
  • F1 hybrid seed will not come true if saved
 

Plant Data

Mature Size 24 - 30 inches tall. 12 - 18 inches wide.
Sun Exposure Partial Shade - Full Sun
Moisture Tolerance Medium
Zones 3a - 8b (Usually hardy to -40° F)
Tags Annual, Annual in Chicago, Attracts Birds, Attracts Butterflies, Attracts Hummingbirds, Attracts Pollinators, Attracts Wildlife, Deciduous, Deer Resistant, Extended Bloom Time, Filler, Full Sun, Good for Beginners, Good for Borders, Good for Cut Flowers, Medium, Partial Shade, Partial Sun, Rabbit Resistant, Showy Flowers, Tender Perennial, Well-Drained Soil
Bloom Period May to Frost
Flower Color Lavender To Purplish-Blue
Foliage Color
 

More Info from Experts

Photos of This with...

Archangel Blue Bicolor Summer Snapdragon, Raspberry Archangel Angelonia, Solenia Yellow Begonia, Valiant Apricot Upright Vinca, Valiant Burgundy Vinca, Dahlietta Blanca, Curry Plant, Bright Ideas Lime Sweet Potato, Lucky Lemon Glow Shrub Verbena, German Myrtle, Americana White Zonal Geranium, Nicoletta Swedish Ivy, Friendship Sage, Persian Shield, Degroot's Spire American Arborvitae, Zahara Raspberry Lemonade Mix Zinnia,
 
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Pricing and Availability History

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Past Availability
2025 : 02/05 - 07/12
2024 : 02/08 - 06/15
2023 : 03/02 - 05/14

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Field-Grown vs. Greenhouse-Grown Plants

Plants which are well-adapted to our local climate are most often field-grown (outside). Field-grown plants are generally cheaper and have the advantage of already somewhat acclimated to our cold winters, but that means they’re not artificially far along in the spring and tend to bloom at the normal time in our area.

Spring annuals and tender perennials are typically grown in Greenhouses so they can be ready and luxurious exactly when customers want them. Some perennials are also “forced” into early bloom in greenhouses. In May, there can be a very big difference between field-grown and greenhouse-grown plants of the same type. The latter typically look good right away (so they’re a great choice where that’s important), but we typically pay a premium for it.


Estimated Recipe Cost

The cost of this recipe's ingredients will vary depending on the season and the sizes and varieties you select.


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To secure the best prices for club members and make sure we know the current plants available from each nursery, we take orders only a couple of times a month.

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No Pricing or Availability Right Now

We order from a rotating cast of the best nurseries in the Great Lakes region. It looks like we've offered this plant in the past, but the nurseries we're working with this week don't appear to have it in stock at the moment.

Our goal is to bring as many plants together under "one roof" as possible, so we'll try hard to make it available again in the future!