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Native Plant Trust: Go Botany Discover thousands of New England plants

Petasites hybridus — butterbur sweet-coltsfoot

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Facts

Butterbur sweet-coltsfoot is native to Europe and an occasional visitor to North America. This distinctive wetland plant has unmistakable flowers as well as giant rhubarb-like leaves up to three feet across. Clinical trials have shown that extracts of butterbur root are effective in reducing frequency and severity of migraine.

Habitat

Anthropogenic (man-made or disturbed habitats), meadows and fields, shores of rivers or lakes

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
  • terrestrial
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Vermont
Leaf type
leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
Leaf arrangement
basal: the leaves are growing only at the base of the plant
Leaf blade edges
the edge of the leaf blade has teeth
Flower type in flower heads
the flower head has disk flowers only, and lacks the strap-shaped flowers
Ray flower color
NA
Tuft or plume on fruit
at least a part of the plume is made up of fine bristles
Spines on plant
the plant has no spines
Leaf blade length
100–300 mm
Disk flower number
  • 11-20
  • more than 50
Show all characteristics

  • Flowers

    Bract color
    the bracts are colored, or at least tinged with, pink, red or purple
    Bract cycle number
    • there are two main cycles of bracts
    • there is one main cycle of bracts
    Bract keels
    there is one distinct keel on the bracts
    Bract margins
    there are few or no fine hairs along the bract margins
    Bract outer side hair type
    the bracts are not hairy on their outer surface
    Bract outer side hairs
    the bracts are not hairy on their outer surfaces
    Bract shape
    • the main bracts are oblanceolate (widest near the tip, but otherwise narrow and tapering)
    • the main bracts are oblong (roughly rectangular but rounded at the ends)
    Bract spines
    the bracts have no spines
    Bract tip extension appearance
    NA
    Bract tip extension edge
    there are no projections from the bract tips
    Bract tip orientation
    the bracts are pressed against the plant, or spreading out at the tips
    Bract tip shape
    • the tips of the bracts acute (have a sharp point)
    • the tips of the bracts are obtuse (have a blunt point)
    Bract width
    5–16
    Bracts
    the bracts in separate cycles are similar or gradually changing from the outer to inner cycles
    Disk flower color
    blue to purple
    Disk flower lobe number
    5
    Disk flower number
    • 11-20
    • more than 50
    Disk flower reproductive parts
    the disk flower has either only pollen- or only seed-producing parts
    Disk flower shape
    the disk flower is tube-shaped (cylindrical), or gradually widening like a funnel
    Flower head number
    • each flowering stem has four or more flower heads on it
    • each flowering stem has only one to three flower heads on it
    Flower head outer flowers
    at the outer edge of the flower head, the flowers have no enlarged lobe or strap, and are of similar size as those in the center of the disk
    Flower head platform
    the base has no bristles or papery scales
    Flower head platform surface
    NA
    Flower head position
    some or all the flower heads are grouped in clusters of two or more
    Flower head profile
    • the disk is flat or nearly flat across the top
    • the disk is rounded across the top
    Flower head shape
    • NA
    • the flower head is shaped like a cone with the point up
    Flower type in flower heads
    the flower head has disk flowers only, and lacks the strap-shaped flowers
    Height of flower head base
    2.5–8.5 mm
    Inflorescence branching (Solidago)
    NA
    Inflorescence shape
    the inflorescence is not flat-topped but appears rounded, with some flower heads distinctly higher than others
    Inflorescence stem
    the stem of the inflorescence is not hairy
    Ovary cross-section
    the ovary has five or more corners in cross-section
    Ovary hair type
    the ovary has no hairs on it
    Ovary hairs
    the ovary has no hairs on it
    Ovary lines or ribs
    • there are four to six lines or ribs visible on the ovary
    • there are seven to nine ribs visible on the ovary
    • there are ten or more ribs visible on the ovary
    Ovary profile
    in profile, the ovary is very narrow
    Peduncle hair type
    the hairs on the peduncles appear tangled or woolly
    Peduncle hairs
    the peduncles are hairy
    Ray flower color
    NA
    Ray flower reproductive parts
    NA
    Ray flowers
    0
    Ray length
    0 mm
    Reproductive system
    all the flowers on some plants have carpels, while all the flowers on other plants have stamens
    Scale tip
    NA
    Smaller bracts at base of bracts
    there is a cycle of much smaller bracts outside the cycle of larger and longer bracts

  • Fruits or seeds

    Number of pappus parts
    1
    Ovary length in developed fruit
    Up to 3 mm
    Seed hair tuft details
    the pappus hairs are smooth and plain
    Seed hair tuft tips
    the pappus hairs are slender
    Seed tuft scale number
    0
    Seed tuft type
    the pappus is made of very fine hairs or bristles
    Top of disk flower ovary
    NA
    Tuft or plume on fruit
    at least a part of the plume is made up of fine bristles

  • Glands or sap

    Sap
    the sap is clear and watery

  • Growth form

    Growth form
    the plant has one or more free-standing stems
    Plant lifespan
    the plant is perennial, it shows evidence of previous year's leaves, stems or stem bases
    Spines on plant
    the plant has no spines
    Underground organs
    the plant has a rhizome (a horizontal underground stem with roots growing from it)

  • Leaves

    Hairs on underside of leaf blade
    the underside of the leaf is fuzzy or hairy
    Hairs on upper side of leaf blade
    the upper side of the leaf is not hairy, or has very few hairs
    Leaf arrangement
    basal: the leaves are growing only at the base of the plant
    Leaf blade base
    • the leaf has a distinct petiole
    • the leaf has no petiole
    Leaf blade base shape
    the base of the leaf is cordate (heart-shaped) or sagittate (arrow-shaped)
    Leaf blade bloom
    the underside of the leaf has no noticeable bloom
    Leaf blade edges
    the edge of the leaf blade has teeth
    Leaf blade hairs
    the leaf blade has tangled or woolly-looking hairs
    Leaf blade length
    100–300 mm
    Leaf blade shape
    • NA
    • the leaf blade is cordate (heart-shaped with backward-facing rounded lobes), or sagittate (arrow-shaped with backward-facing pointed lobes)
    • the leaf blade is orbicular (roughly circular, as wide as long)
    Leaf blade surface colors
    there is no noticeable color variation on the upper surface of the leaf
    Leaf blade tip
    the tip of the leaf blade is rounded, with no point
    Leaf blade veins
    NA
    Leaf blade width
    100–300 mm
    Leaf disposition
    the lower leaves are larger, toothier, and/or on longer stalks than the upper leaves
    Leaf spines
    there are no spines on the leaf edges
    Leaf stalk
    • the leaves have leaf stalks
    • the leaves have no leaf stalks, but attach directly to the stem
    Leaf tufts in axils
    there are no clusters of smaller leaves
    Leaf type
    leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
    Leaflet number
    0
    Specific leaf type
    the leaf has lobes that radiate from the base, somewhat like a hand

  • Place

    Habitat
    • terrestrial
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Vermont
    Specific habitat
    • man-made or disturbed habitats
    • meadows or fields
    • shores of rivers or lakes

  • Stem, shoot, branch

    Flowering stem cross-section
    the flowering stem is circular, or with lots of small angles
    Leaves on stem
    the flowering stem has no leaves above the base
    Stem internode hair direction
    the hairs point mostly upwards to outwards
    Stem internode hair type
    at least some of the hairs on the stem are tangled, matted or woolly
    Stem internode hairs
    the stem has hairs between the nodes

Wetland status

Occurs in wetlands or non-wetlands. (Wetland indicator code: FAC)

In New England

Distribution

Connecticut
present
Maine
present
Massachusetts
present
New Hampshire
present
Rhode Island
absent
Vermont
present

Conservation status

Exact status definitions can vary from state to state. For details, please check with your state.

Massachusetts
not applicable (S-rank: SNA)

From Flora Novae Angliae dichotomous key

2.  Petasites hybridus (L.) P.G. Gaertn., B. Mey., & Scherb. E

butterbur sweet-coltsfoot. Petasites officinalis Moench; P. vulgaris Hill • CT, MA, ME, NH, VT. Roadsides, fields, stream banks.

Native to North America?

No

Sometimes confused with

Petasites japonicus:
disk corollas cream-white, bracts of scape usually green, the one subtending the lowermost branch of the capitulescence 17–40 mm wide, and leaf blades with mostly 5 pairs of lateral veins emerging along the inner margins of the basal sinus (vs. P. hybridus, with the disk corollas largely purple, bracts of scape usually purple or purple-tinged, the one subtending the lowermost branch of the capitulescence 5–16 mm wide, and leaf blades with 2–5 pairs of lateral veins emerging along the inner margins of the basal sinus).

Synonyms

  • Petasites officinalis Moench
  • Petasites vulgaris Hill

Family

Asteraceae

Genus

Petasites