purple loosestrife
Family
LythraceaeScientific Name
Lythrum salicaria
Other Common Names:
salicaire
spiked loosestrife
purple lythrum
rainbow weed
Habit
Seedlings have ovate hairless cotyledons 3-6 mm long and 2-3 mm wide. Mature plants reach heights of 50-150 cm tall and arise from thick fleshy roots. Stems have several branches covered with soft hairs and are capable of spreading by bits of stem, root and seed.
Leaves
Leaves slightly hairy are lance shaped and can be opposite or in whorls of 3.
Identifying Characteristics
Found in moist places, purple flowers, and opposite leaves.
Flower Seed Head
Flowers appear in spikes on the end of branches and are purple with 5-7 petals, 7-10 mm long.
Seed Fruit
Fruit are 2 chambered capsules containing several seeds. A single plant can produce as many 2 million seeds a year.
Where Found
Found throughout the northeastern United States this plant can destroy wetlands taking the place of native vegetation. This species is a problem for cranberry bogs, spring flooded pastures, ditches, canals, and roadsides.
Growth Habit
upright and nonwoody
Thorns or Spines
not present
Approximate Flower Diameter
dime
Dominant Flower Color
Varies:
purple,
red
Flower Symmetry
radial symmetery
Leaf Hairs
Varies:
has hairs,
no hairs
Leaf Shape
Varies:
heart,
needle,
lance,
oval
Leaf Arrangement
Varies:
alternate,
opposite,
whorled
Leaf Margin
entire
Leaf Structure
simple
Leaf Stalk
none
Stem Hairs
Varies:
has hairs,
no hairs
Stem Cross Section
round or oval
Milky Sap
not present
Root Structure
taproot
Life Cycle
perennial
Plant Type
Herb