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Hypericum densiflorum — bushy St. John's-wort

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Facts

Bushy St. John's-wort reaches the northern edge of its range in New England, where it is considered non-native. This attractive plant is covered with an explosion of yellow flowers in mid- to late summer. In fall, the foliage turns a deep yellow, and in winter, the glossy, coppery bark of mature shrubs add visual interest to the garden. This versatile plant grows in a variety of soil conditions and can even grace rock gardens.

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
Massachusetts
Growth form
the plant is a shrub (i.e., a woody plant with several stems growing from the base)
Leaf type
the leaf blade is simple (i.e., lobed or unlobed but not separated into leaflets)
Leaves per node
there are two leaves per node along the stem
Leaf blade edges
the edge of the leaf blade has no teeth or lobes
Leaf duration
the leaves drop off in winter (or they wither but persist on the plant)
armature on plant
the plant does not have spines, prickles, or thorns
Leaf blade length
10–50 mm
Leaf blade width
3–11 mm
Leaf stalk
the leaves have no leaf stalks, but attach directly to the stem
Fruit type (general)
the fruit is dry and splits open when ripe
Bark texture
the bark of an adult plant is thin and smooth
Twig winter color
  • brown
  • red
Bud scale number
there are no scales on the winter buds
Show all characteristics

  • Buds or leaf scars

    Bud scale number
    there are no scales on the winter buds
    Bud scar shape (Fraxinus)
    NA

  • Flowers

    Carpels fused
    the carpels are fused to one another
    Enlarged sterile flowers
    there are no enlarged sterile flowers on the plant
    Flower petal color
    • orange
    • yellow or green
    Flower symmetry
    there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
    Hairs on ovary (Amelanchier)
    NA
    Hypanthium present
    the flower does not have a hypanthium
    Inflorescence type
    • the flowers grow out of the axil (point where a branch or leaf is attached to the main stem)
    • the inflorescence has only one flower on it
    • the inflorescence is a corymb (with long lower branches and shorter upper branches, giving it a more or less flat-topped look)
    • the inflorescence is a dichasial cyme (an axis with a terminal flower, below it a pair of branches, each with a terminal flower, these branches may in turn each have a pair of branches and so on)
    Number of pistils
    1
    Ovary position
    the ovary is above the point of petal and/or sepal attachment
    Petal and sepal arrangement
    the flower includes two cycles of petal- or sepal-like structures
    Petal appearance
    the petals are thin and delicate, and pigmented (colored other than green or brown)
    Petal fusion
    the perianth parts are separate
    Sepal cilia (Ilex)
    NA
    Stamen number
    13 or more

  • Fruits or seeds

    Berry color
    NA
    Fruit tissue origin
    there are no flower parts that form part of the fruit
    Fruit type (general)
    the fruit is dry and splits open when ripe
    Fruit type (specific)
    the fruit is a capsule (splits along two or more seams, apical teeth or pores when dry, to release two or more seeds)
    Nut with spines (Fagaceae)
    NA
    Wings on fruit
    there are no wings on the fruit

  • Glands or sap

    Sap color
    the sap is clear and watery
    Stalked glands on fruit (Rosa)
    NA

  • Growth form

    Growth form
    the plant is a shrub (i.e., a woody plant with several stems growing from the base)

  • Leaves

    Hairs on upper side of leaf blade
    the upper side of the leaf is not hairy, or has very few hairs
    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
    Leaf blade edges
    the edge of the leaf blade has no teeth or lobes
    Leaf blade edges (Acer)
    NA
    Leaf blade hairs
    at least some of the hairs on the leaf blade have glands at their tips
    Leaf blade length
    10–50 mm
    Leaf blade scales
    there are no scales on the leaf blades
    Leaf blade shape
    • the leaf blade is elliptic (widest near the middle and tapering at both ends)
    • the leaf blade is linear (very narrow with more or less parallel sides)
    • the leaf blade is oblanceolate (lance-shaped, but with the widest point above the middle of the leaf blade)
    Leaf blade translucent dots
    the leaf blade has translucent dots on it
    Leaf blade width
    3–11 mm
    Leaf duration
    the leaves drop off in winter (or they wither but persist on the plant)
    Leaf lobe tips (Quercus)
    NA
    Leaf midrib glands
    the midrib of the leaf blade lacks glands on the upper surface
    Leaf stalk
    the leaves have no leaf stalks, but attach directly to the stem
    Leaf stalk nectaries
    • NA
    • there are no nectaries on the leaf stalk
    Leaf teeth
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf teeth hairs (Carya)
    NA
    Leaf type
    the leaf blade is simple (i.e., lobed or unlobed but not separated into leaflets)
    Leaves per node
    there are two leaves per node along the stem
    Specific leaf type
    the leaves are simple (i.e., lobed or unlobed but not separated into leaflets

  • Place

    Habitat
    terrestrial
    New England state
    Massachusetts
    Specific habitat
    • man-made or disturbed habitats
    • meadows or fields

  • Scent

    Plant odor
    the plant does not have much of an odor, or it has an unpleasant or repellant odor

  • Stem, shoot, branch

    Aerial roots
    the plant has no aerial roots
    Bark texture
    the bark of an adult plant is thin and smooth
    Branch brittleness (willows only)
    NA
    Branch cross-section
    the branch is circular in cross-section, or it has five or more sides, so that there are no sharp angles
    First-year cane (Rubus)
    NA
    Twig papillae (Vaccinium species only)
    NA
    Twig winter color
    • brown
    • red
    Wings on branch
    the branch does not have wings on it
    armature on plant
    the plant does not have spines, prickles, or thorns

Wetland status

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

In New England

Distribution

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

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

5.  Hypericum densiflorum Pursh E

bushy St. John’s-wort. Hypericum glomeratum Small • MA. Fields, waste areas.

Native to North America?

Yes and no (some introduced)

Sometimes confused with

Hypericum prolificum:
terminal cyme with mostly 3–7 flowers, leaf blades mostly 7–15 mm wide, and capsules 3-5 mm wide (vs. H. densiflorum with the terminal cyme with 7 or more flowers, leaf blades mostly 3–7 mm wide, and capsules 1.5-3 mm wide).

Synonyms

  • Hypericum glomeratum Small

Family

Hypericaceae

Genus

Hypericum