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Purple Loosestrife

Lythrum salicaria (LITH-rum sal-ih-KAIR-ee-ah)

Family: Lythraceae Non-native Herbaceous (3-15 ft)

This plant is problematic and alternatives should be considered. Please see the suggestions in the left-hand column. Purple loosestrife is a perennial weed in the Lythraceae (loosestrife) family native to Africa and Eurasia. Commonily found growing in waste areas, roadsides, and sites with wet soil conditions. The plant will grow from 2 to 6 feet tall Very tolerant of wet sites and full sun. The roots are thick and send out many runners forming an extensive underground network from which new plants can sprout. The showy purple pink flowers appear from mid to late summer and are followed by capsules filled with thousands of tiny seeds that are easily dispersed by wind, water, and animals. It is currently against the law in North Carolina and many other states to sell Purple loosestrife, because it escapes from cultivation and becomes a prolific weed in wetland areas, choking out native vegetation essential for waterfowl. Named cultivars once thought to be non-invasive are now known to cross and develop strains that spread rapidly in the landscape. Purple loosestrife is not recommended nor is it legal for cultivation (is it a noxious weed in North Carolina). Insects, Diseases, and Other Plant Problems: Consider growing native plants. See the list on the sidebar. Listed as invasive by the NC Invasive Plant Council. This species is on the NC noxious weed list.

Source: NC State Extension Gardener Plant Toolbox ↗ NC State Extension Gardener Plant Toolbox, 42 attributes.

How it fits the guild

Guild layer 4 - Herbaceous (3-15 ft)
See companions & conflicts ↓

Companions & Conflicts

Curated pairwise relationships between this plant and others in the library — who feeds whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.

No curated interactions recorded for this species yet.

Also noted by NC State

Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.

Full plant profile

Growing Conditions
Plant type
Herbaceous Perennial; Perennial; Weed
Life cycle
Perennial
USDA zones
3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
Light
Full sun (6 or more hours of direct sunlight a day)
Soil drainage
Good Drainage | Occasionally Wet
Mature size
Height: 2 ft. 0 in. - 6 ft. 0 in. | Width: 2 ft. 0 in. - 4 ft. 0 in.
Growth rate
Rapid
Maintenance
High
Canopy layer
4 - Herbaceous (3-15 ft)
Form & Appearance
Habit / form
Erect
Leaf arrangement
Opposite; Whorled
Leaf shape
Lanceolate
Leaf feel
Velvety
Leaf size
3-6 inches long
Hairs present
Yes
Leaf detail
The 4 inch long leaves are stemless and lance-shaped and either opposite or whorled in an arrangement.
Flower color
Pink; Purple/Lavender
Flower form
Spike
Flower detail
Intense purplish-pink flowers with 5 to 6 petals yellow centers arranged in 1 foot tall spikes that bloom from early July to September.
Bloom time
Summer
Fruit color
Cream/Tan
Fruit type
Capsule
Fruit detail
Tan capsules that appear as early as July with many tiny seeds aid in the quick dispersion of this plant. Seeds the size of sand spread by wind, water, humans, and animals.
Stem color
Green
Stem detail
4 to 6 sided square shaped stem
Wildlife & Ecology
Native status
Non-native
Origin
Europe, Africa and Asia-Temperate
Distribution
Naturalized and invasive in the USA
Food & Medicine
Fruit type
Capsule
Landscape Use
Garden tags
#purple #invasive #illegal #showy flowers #summer flowers #pink flowers #full sun tolerant #wet soils tolerant #wind dispersed seeds #aggressive #water dispersed seeds #high maintenance #perennial #Noxious Weed (state list) #weedy
Problems & Resistance
Problems
Invasive Species; Weedy
Resistant to
Wet Soil
Propagation
Division; Seed; Stem Cutting

Planted at Hunnicutt

Nobody’s planted this one yet.