Conoclinium Coelestinum

Hardy Ageratum for Monarch Butterflies

Conoclinium coelstinum common names: Blue Boneset, Blue Mistflower, Hardy Ageratum, Wild Ageratum, Eupatorium coelestinum (former botanical name)

Monarch Female Blue Mist Flower
Must-Have Mistflower

Conoclinium Coelestinum Plant Specs

  • Herbaceous perennial flower for USDA hardiness zones 5a-9b (lows -28.9 °C or -20 °F)
  • Native plant to the eastern United States, grown in eastern Canada
  • Fast growing annual ageratum for colder zones
  • Full sun to light shade
  • Height: 1.5 to 3 ft feet
  • Spacing: 2 to 3 feet
  • Disk Flowers
  • Flower color: light purple, violet, blue-purple
  • Leaves: opposite, wide, heart-shaped
  • Stems: thin, upright, bendable
  • Blooms summer through first frost (Jul, Aug, Sep, Oct)

Hardy Ageratum Pros

  • Long flowering period- monarchs seek this out all season
  • A short “filler” plant that works well between some of your showier flowers
  • Care-free plant
  • grows quickly from seed
  • Favorite nectar source of monarchs
  • Provides migration energy for masses of monarchs

Conoclium Coelestinum Cons

  • Can be invasive with seeding and underground rhizomes
  • Blue mistflower spreads by excessive seeding
  • Flowers aren’t showy
  • Susceptible to White Flies and Powdery Mildew

Looking for a mistflower variety better-suited for southern states? Try migration favorite Conoclinium greggii (Gregg’s mistflower)

How to tell two monarch magnet mistflowers apart? Look at their leaves. Find out more about these monarch butterfly plants...
Mistflower Leaf Comparison

Blue Mistflower Plant Propagation

Conoclinium coelestinum is hardy ageratum for monarch butterflies. A top-notch nectar flower from early summer through the monarch migration

Blue Mistflower Growing Tips

  • In Minnesota, we pull our mistflower plants in the fall and let them come back from seed the next season. This keeps the rhizomes from taking over the garden, and the seedlings grow quickly each spring
  • Good option moist meadows and wildflower gardens…will grow in clay soils

Pollinator Plus

Conoclinium coelestinum also attracts bees, moths, painted ladies, skippers, and queen butterflies.

Buy Conoclinium Coelestinum Plants and Seeds

As difficult as the botanical name is to spell and say, always purchase plants searching for this name. Common names are more often misused when labeling plants, so you’ll have best results searching for:

1. Conoclinium coelestinum (wild ageratum) plants and seeds from JB

2. Find More Conoclinum Coelestinum on Etsy

If you’re interested in adding more butterfly plants to your garden, check out our butterfly flowers page

Please post below if you have any questions or comments about growing
Conoclinium coelestinum aka Wild ageratum in your garden:
Share the Joy of Butterflies


  1. Lovely perennial ageratum, but way too invasive. Spreads like wildflower. Do not recommend planting this in your garden, or you will have it everywhere. I planted it years ago, and every year I pull out a ton of it!

  2. Blue Mistflower may be a great butterfly attractor but I regret planting it my garden and planting it in containers. It is EVERYWHERE! I have spent more time pulling out the plants that must have been started from seed because some are 80 feet away from the original plant. The one in the beds took over everything so I spent an afternoon pulling out what I could. I was on a garden tour and one of the visitors said it took years for her to rid her garden of it. I’m sure it will be coming up in my garden for years because I’m sure I am missing some. Just beware if you plant it. Comes up between pavers also!

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