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Blue Boneset Conoclinium coelestinum

Previously known as:

  • Eupatorium coelestinum
Description

Commonly called mistflower, this late summer to fall-blooming herbaceous perennial is native to the Eastern United States. It looks like the annual ageratum and in that regard is sometimes commonly called hardy ageratum. But it is perennial and can spread aggressively by rhizomes and is weedy.

It is a showy native plant that is considered a weed in the coastal plain, growing along roadsides on moist ditch banks. Under cultivation, it becomes a choice perennial with 8 weeks of blue flowers.

This plant prefers moist humusy soils that do not dry out in full sun to partial shade areas.  Purplish stems have toothed deltoid leaves. Blueish purple flowers are fluffy, tubular (to 1/ 2” across).   Cut back taller plants in spring to prevent flopping. This is a great plant to consider for a wildflower garden or naturalized area, does especially well around pond borders as long as spreading roots will not affect other plants.  It is extremely rhizomatous and not recommended for smaller planting areas as it spreads aggressively by its rhizomes and self-seeding. Propagate by clump division in early spring. This plant is moderately resistant to damage from deer. 

Fire Risk: This plant has a low flammability rating.

Insects, Diseases, or Other Plant Problems:  Leaf miners and aphids may visit. This plant has some susceptibility to powdery mildew.  Plants tend to flop and may need support. Spreading tendencies must be watched, particularly if planted in a perennial border.

Family name Asteraceae (Compositae)

Quick ID Hints:

  • Erect herb with clusters of small heads of tubular flowers
  • Flowers bluish-purple
  • Leaves opposite, deltoidly ovate, crenately serrat

Erect herbaceous perennial to 2-3' tall. 

Blooms from midsummer til frost; staking may be required; rapid growth, spreads easily & can become invasive in beds; frequent divion is needed; utilized for cut flowers,color when combined with whites & yellow, late season bloomer. 

Prefers full sun and moist soils; pest/disease problems.

Cultivars / Varieties:
Tags:
#purple#butterflies#showy flowers#blue#wildlife plant#purple flowers#wildflowers#weedy#nectar plant#blue flowers#damp soil#wet sites#pond margins#food source#low flammability#NC native#deer resistant#native garden#fire resistant#borders#self-seeding#agressive#pollinator plant#native wildflower#fantz#aggresive#fall food source
 
Cultivars / Varieties:
Tags:
#purple#butterflies#showy flowers#blue#wildlife plant#purple flowers#wildflowers#weedy#nectar plant#blue flowers#damp soil#wet sites#pond margins#food source#low flammability#NC native#deer resistant#native garden#fire resistant#borders#self-seeding#agressive#pollinator plant#native wildflower#fantz#aggresive#fall food source
  • Attributes:
    Genus:
    Conoclinium
    Species:
    coelestinum
    Family:
    Asteraceae
    Life Cycle:
    Perennial
    Recommended Propagation Strategy:
    Division
    Root Cutting
    Seed
    Country Or Region Of Origin:
    Canada, Cuba, southeastern United States, NC
    Wildlife Value:
    The nectar-rich flowers are attractive to butterflies and other pollinators. Birds enjoy the seeds.
    Play Value:
    Attractive Flowers
    Attracts Pollinators
    Wildlife Food Source
  • Whole Plant Traits:
    Plant Type:
    Herbaceous Perennial
    Native Plant
    Wildflower
    Leaf Characteristics:
    Deciduous
    Habit/Form:
    Clumping
    Spreading
    Growth Rate:
    Rapid
    Maintenance:
    High
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Partial Shade (Direct sunlight only part of the day, 2-6 hours)
    Soil Texture:
    High Organic Matter
    Soil Drainage:
    Moist
    NC Region:
    Coastal
    Mountains
    Piedmont
  • Fruit:
    Display/Harvest Time:
    Fall
  • Flowers:
    Flower Color:
    Blue
    Pink
    Purple/Lavender
    Flower Inflorescence:
    Corymb
    Flower Value To Gardener:
    Showy
    Flower Bloom Time:
    Fall
    Summer
    Flower Shape:
    Tubular
    Flower Size:
    < 1 inch
    Flower Description:
    Thistle like aster flowers that lack rays. It has numerous small, fluffy, tubular, blue-purple flowers (to 1/ 2” across) with discoid heads that bloom from July to October in dense flat topped terminal clusters (corymbs). In terminal, branched, clusters of small heads of 5 mm diam. bluish-purple, tubular.
  • Leaves:
    Leaf Characteristics:
    Deciduous
    Leaf Color:
    Green
    Leaf Type:
    Simple
    Leaf Arrangement:
    Opposite
    Leaf Shape:
    Cuneate
    Deltoid
    Ovate
    Leaf Margin:
    Dentate
    Serrate
    Hairs Present:
    No
    Leaf Length:
    1-3 inches
    Leaf Description:
    Coarsely-toothed, ovate-deltoid leaves (to 3” long). The leaves are opposite and triangular. Opposite, simple, deltoidly-ovate, acute, broad cuneate to truncate, crenately-serrate, puberulent, lateral veins typically end in tooth.
  • Stem:
    Stem Color:
    Green
    Purple/Lavender
    Red/Burgundy
    Stem Is Aromatic:
    No
    Stem Surface:
    Hairy (pubescent)
    Stem Description:
    Downy purplish stems
  • Landscape:
    Landscape Location:
    Pond
    Landscape Theme:
    Butterfly Garden
    Native Garden
    Pollinator Garden
    Water Garden
    Design Feature:
    Border
    Mass Planting
    Attracts:
    Butterflies
    Moths
    Pollinators
    Songbirds
    Resistance To Challenges:
    Deer
    Fire
    Wet Soil
    Problems:
    Weedy