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

Artemisia biennis — biennial wormwood

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Facts

Biennial wormwood is considered native to the northwestern United States, but is introduced and weedy in the majority of its current range, including in New England. It is considered a noxious weed of crops in the northern Great Plains, especially since the rise of no-till agricultural practices between 1990 and 2000.

Habitat

Anthropogenic (man-made or disturbed habitats), meadows and fields

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
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Leaf type
leaves are simple (lobed or unlobed but not separated into leaflets)
Leaf arrangement
alternate: there is one leaf per node along the stem
Leaf blade edges
  • the edge of the leaf blade has lobes, or it has both teeth and lobes
  • 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
NA
Spines on plant
the plant has no spines
Leaf blade length
40–130 mm
Flower head width
1.5–4 mm
Disk flower number
  • 11-20
  • 21-50
Show all characteristics
  • Flowers

    Bases of bract appendages
    NA
    Bract cycle number
    there are three or more cycles of bracts
    Bract inner side hairs
    the bracts are not hairy on their inner surfaces
    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 separation
    the bracts appear completely unconnected to one another on all flower heads
    Bract shape
    • the main bracts are elliptic (widest near the middle and tapered towards the base and tip)
    • the main bracts are obovate (roughly egg-shaped, but widest near the tip)
    Disk flower color
    yellow
    Disk flower lobe number
    5
    Disk flower number
    • 11-20
    • 21-50
    Disk flower reproductive parts
    • the disk flower has both pollen- and seed-producing parts
    • the disk flower has either only pollen- or only seed-producing parts
    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 width
    1.5–4 mm
    Flower type in flower heads
    the flower head has disk flowers only, and lacks the strap-shaped flowers
    Height of flower head base
    2–3 mm
    Inflorescence branching (Solidago)
    NA
    Inflorescence shape
    the inflorescence is not flat-topped but appears rounded, with some flower heads distinctly higher than others
    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
    Ovary profile
    in profile, the ovary is roughly elliptical (widest in the middle, tapering to both ends)
    Ray flower color
    NA
    Ray flower reproductive parts
    NA
    Ray flowers
    0
    Ray length
    0 mm
    Reproductive system
    some of the flowers on the plant have only carpels or stamens, while others have both carpels and stamens
    Scale tip
    NA
    Width of flower head base
    1.5–4 mm
  • Fruits or seeds

    Number of pappus parts
    0
    Ovary length in developed fruit
    0.2–0.9 mm
    Seed hair tuft bases
    NA
    Seed hair tuft color
    NA
    Seed hair tuft details
    NA
    Seed hair tuft length
    0 mm
    Seed hair tuft tips
    NA
    Seed hairs uniform
    NA
    Seed tuft scale number
    0
    Seed tuft type
    there is no pappus on the ovary
    Top of disk flower ovary
    NA
    Tuft or plume on fruit
    NA
  • 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 annual, it lacks evidence of previous years' growth
    • the plant is biennial, it appears as either first year (non-reproductive) plants or second year plants with flowers or fruit
    Spines on plant
    the plant has no spines
    Underground organs
    there is a thickened taproot on the plant
  • Leaves

    Hairs on underside of leaf blade
    the underside of the leaf is not hairy, or has very few hairs
    Hairs on upper side of leaf blade
    the upper side of the leaf is not hairy, or has very few hairs
    Leaf arrangement
    alternate: there is one leaf per node along the stem
    Leaf blade base
    • the leaf has a distinct petiole
    • the leaf has no petiole
    Leaf blade base shape
    • the base of the leaf blade is cuneate (wedge-shaped, tapers to the base with relatively straight, converging edges), or narrow
    • the base of the leaf blade is truncate (ends abruptly in a more or less straight line as though cut off)
    Leaf blade bloom
    the underside of the leaf has no noticeable bloom
    Leaf blade edges
    • the edge of the leaf blade has lobes, or it has both teeth and lobes
    • the edge of the leaf blade has teeth
    Leaf blade hairs
    NA
    Leaf blade length
    40–130 mm
    Leaf blade shape
    • the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
    • the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
    Leaf blade surface colors
    there is no noticeable color variation on the upper surface of the leaf
    Leaf blade width
    15–40 mm
    Leaf disposition
    the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
    Leaf spines
    there are no spines on the leaf edges
    Leaf stalk
    the leaves have no leaf stalks, but attach directly to the stem
    Leaf tip extension
    NA
    Leaf type
    leaves are simple (lobed or unlobed but not separated into leaflets)
    Leaflet number
    0
    Specific leaf type
    • the leaf has a row of two or more lobes on each side of the central axis
    • the leaf has a row of two or more lobes on each side of the central axis, and each lobe itself has rows of lobes on each side of the lobe's central axis
  • Place

    Habitat
    terrestrial
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • man-made or disturbed habitats
    • meadows or fields
  • Scent

    Plant odor
    the plant does not have much of an odor
  • Stem, shoot, branch

    Flowering stem cross-section
    the flowering stem is circular, or with lots of small angles
    Leaves on stem
    there is at least one full leaf above the base of the flowering stem
    Stem bloom
    there is no powdery or waxy film on the stem
    Stem internode hair direction
    NA
    Stem internode hair length
    0 mm
    Stem internode hair type
    the stem has no hairs between the nodes
    Stem internode hairs
    the stem has no hairs between the nodes
    Stem wings
    the stem does not have wings on it

Wetland status

Usually occurs in wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)

In New England

Distribution

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

4.  Artemisia biennis Willd. E

biennial wormwood. CT, MA, ME, NH, RI, VT. Roadsides, railroads, fields, disturbed soil.

Native to North America?

Yes

Sometimes confused with

Artemisia annua:
lower heads nodding and borne on evident stalks and foliage aromatic (vs. A. biennis, with flower heads upright on inconspicuous stalks and foliage with little or no scent).

Family

Asteraceae

Genus

Artemisia