Purple loosestrife
Encyclopedia
Lythrum salicaria is a flowering plant
belonging to the family Lythraceae
, native to Europe
, Asia
, northwest Africa
, and southeastern Australia
. It should not be confused with other plants sharing the name loosestrife
that are members of the family Primulaceae
. Other names include spiked loosestrife, or purple lythrum; in French
it is salicaire, and in Chinese
千屈菜 qian qu cai.
.jpg)
Lythrum salicaria is a herbaceous
perennial plant
, that can grow 1-1.5 m tall, forming clonal colonies 1.5 m or more in width with numerous erect stems growing from a single woody root mass. The stems are reddish-purple or red to purple and square in cross-section. The leaves are lanceolate, 3–10 cm long and 5–15 mm broad, downy and sessile, and arranged opposite or in whorls of three.
The flower
s are reddish purple, 10–20 mm diameter, with six petals (occasionally five) and 12 stamens, and are clustered tightly in the axils of bract
s or leaves; there are three different flower types, with the stamens and style of different lengths, short, medium or long; each flower type can only be pollinated by one of the other types, not the same type, thus ensuring cross-pollination between different plants.
The fruit
is a small 3–4 mm capsule
containing numerous minute seed
s. Flowering lasts throughout the summer. When the seeds are mature, the leaves often turn bright red through dehydration in early autumn; the red colour may last for almost two weeks. The dead stalks from previous growing seasons are brown.
L. salicaria is very variable in leaf shape and degree of hairiness, and a number of subspecies and varieties have been described, but it is now generally regarded as monotypic with none of these variants being considered of botanical significance. The species Lythrum intermedium Ledeb. ex Colla is also now considered synonymous.
s and butterflies
.
A number of insect
s use Lythrum salicaria as a food resource.
The black-margined loosestrife beetle Galerucella calmariensis
is a brown beetle with a black line on its thorax. The adult feeds on the leaves of the plant, producing characteristic round holes. Its larvae destroy tender leaf buds and strip the tissue from the leaves. The golden loosestrife beetle Galerucella pusilla is nearly identical to G. calmariensis, but usually lacks the black thoracic line. Its feeding habits are also quite similar to the other leaf beetle.
The loosestrife root weevil Hylobius transversovittatus
is a large red nocturnal weevil, which spends its nights feeding on leaves and leaf buds. The larvae emerge from their eggs and immediately burrow into the root of the plant, which they feed on continuously for over a year. This root damage stunts the plant's growth and ability to create seeds. If several larvae inhabit the same root, the plant can be killed.
The loosestrife flower weevil Nanophyes marmoratus is a tiny weevil which lays a single egg in each flower. When the larvae emerge they eat the flowers' ovaries, and the plant is unable to create seeds. The larvae usually proceed to hollow out the flower buds and use them as safe places to pupate.
Caterpillar
s of the engrailed moth (Ectropis crepuscularia
), a polyphagous geometer moth, also feed on Purple Loosestrife.
medicinal herb to treat diarrhoea and dysentery
; it is considered safe to use for all ages, including babies. It is also cultivated as an ornamental plant
in gardens. The flowers are showy and bright, and a number of cultivar
s have been selected for variation in flower colour, including 'Atropurpureum' with dark purple flowers, 'Brightness' with deep pink flowers, 'Happy' with red flowers on a short (60 cm) stem, 'Purple Spires' with purple flowers on a tall stem, and 'Roseum Superbum' with large pink flowers. It has also been introduced in many areas of North America by bee keepers, due to its abundunce of flowers which provide a large source of nectar.
and North America
where it is now widely naturalized and officially listed in some controlling agents. Infestations result in dramatic disruption in water flow in rivers and canals, and a sharp decline in biological diversity as native food and cover plant species, notably cattail
s, are completely crowded out, and the life cycles of organisms from waterfowl to amphibians to algae are affected.
A single plant may produce up to three million tiny seeds annually. Easily carried by wind and water, the seeds germinate in moist soils after overwintering. The plant can also sprout anew from pieces of root left in the soil or water. Once established, loosestrife stands are difficult and costly to remove by mechanical and chemical means.
Plants marketed under the name "European wand loosestrife" (L. virgatum) are the same species despite the different name. In some cases the plants sold are sterile, which is preferable.
In North America, purple loosestrife may be distinguished from similar native plants (e.g. fireweed
Epilobium angustifolium, blue vervain Verbena hastata, Liatris
Liatris spp., and spiraea
(Spiraea douglasii) by its angular stalks which are square in outline, as well by it leaves, which are in pairs that alternate at right angle and are not serrated.
. Research began in 1985 and today the plant is managed well with a number of insects that feed on it. Five species of beetle
use purple loosestrife as their natural food source and they can do significant damage to the plant. The beetles used as biological control agents include two species of leaf beetle
: Galerucella calmariensis
and Galerucella pusilla, and three species of weevil
: Hylobius transversovittatus
, Nanophyes breves, and Nanophyes marmoratus. Infestations of either of the Galerucella species is extremely effective in wiping out a stand of purple loosestrife, defoliating up to 100% of the plants in an area. The moth Ectropis crepuscularia is a pest species itself and unsuitable for biological control.
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
belonging to the family Lythraceae
Lythraceae
Lythraceae are a family of flowering plants. It includes about 620 species of mostly herbs, with some shrubs and trees, in 31 genera. Major genera include Cuphea , Lagerstroemia , Nesaea , Rotala , and Lythrum...
, native to Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, northwest Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, and southeastern Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. It should not be confused with other plants sharing the name loosestrife
Loosestrife
Loosestrife is the common name of a number of different flowering plants. The species belong to two taxonomic genera, Lythrum, within the family Lythraceae, and Lysimachia, within the family Primulaceae.Lythrum species known as loosestrife include:...
that are members of the family Primulaceae
Primulaceae
Primulaceae is a family of flowering plants with about 24 genera, including some favorite garden plants and wildflowers. It is also known as the primrose family.- Genera :...
. Other names include spiked loosestrife, or purple lythrum; in French
French language
French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...
it is salicaire, and in Chinese
Chinese language
The Chinese language is a language or language family consisting of varieties which are mutually intelligible to varying degrees. Originally the indigenous languages spoken by the Han Chinese in China, it forms one of the branches of Sino-Tibetan family of languages...
千屈菜 qian qu cai.
Description
Herbaceous
A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...
perennial plant
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...
, that can grow 1-1.5 m tall, forming clonal colonies 1.5 m or more in width with numerous erect stems growing from a single woody root mass. The stems are reddish-purple or red to purple and square in cross-section. The leaves are lanceolate, 3–10 cm long and 5–15 mm broad, downy and sessile, and arranged opposite or in whorls of three.
The flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s are reddish purple, 10–20 mm diameter, with six petals (occasionally five) and 12 stamens, and are clustered tightly in the axils of bract
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
s or leaves; there are three different flower types, with the stamens and style of different lengths, short, medium or long; each flower type can only be pollinated by one of the other types, not the same type, thus ensuring cross-pollination between different plants.
The fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
is a small 3–4 mm capsule
Capsule (fruit)
In botany a capsule is a type of simple, dry fruit produced by many species of flowering plants. A capsule is a structure composed of two or more carpels that in most cases is dehiscent, i.e. at maturity, it splits apart to release the seeds within. A few capsules are indehiscent, for example...
containing numerous minute seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s. Flowering lasts throughout the summer. When the seeds are mature, the leaves often turn bright red through dehydration in early autumn; the red colour may last for almost two weeks. The dead stalks from previous growing seasons are brown.
L. salicaria is very variable in leaf shape and degree of hairiness, and a number of subspecies and varieties have been described, but it is now generally regarded as monotypic with none of these variants being considered of botanical significance. The species Lythrum intermedium Ledeb. ex Colla is also now considered synonymous.
Associated insects
The flowers are pollinated by long-tongued insects, including beeBee
Bees are flying insects closely related to wasps and ants, and are known for their role in pollination and for producing honey and beeswax. Bees are a monophyletic lineage within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila...
s and butterflies
Butterfly
A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured...
.
A number of insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s use Lythrum salicaria as a food resource.
The black-margined loosestrife beetle Galerucella calmariensis
Galerucella calmariensis
Galerucella calmariensis is a species of leaf beetle in the family Chrysomelidae. It is commonly known as the black-margined loosestrife beetle and is native to Europe and Asia where both adults and larvae feed on purple loosestrife...
is a brown beetle with a black line on its thorax. The adult feeds on the leaves of the plant, producing characteristic round holes. Its larvae destroy tender leaf buds and strip the tissue from the leaves. The golden loosestrife beetle Galerucella pusilla is nearly identical to G. calmariensis, but usually lacks the black thoracic line. Its feeding habits are also quite similar to the other leaf beetle.
The loosestrife root weevil Hylobius transversovittatus
Hylobius transversovittatus
Hylobius transversovittatus is a species of weevil in the family Curculionidae. It is native to the Old World where both adults and larvae feed on purple loosestrife...
is a large red nocturnal weevil, which spends its nights feeding on leaves and leaf buds. The larvae emerge from their eggs and immediately burrow into the root of the plant, which they feed on continuously for over a year. This root damage stunts the plant's growth and ability to create seeds. If several larvae inhabit the same root, the plant can be killed.
The loosestrife flower weevil Nanophyes marmoratus is a tiny weevil which lays a single egg in each flower. When the larvae emerge they eat the flowers' ovaries, and the plant is unable to create seeds. The larvae usually proceed to hollow out the flower buds and use them as safe places to pupate.
Caterpillar
Caterpillar
Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...
s of the engrailed moth (Ectropis crepuscularia
Engrailed
The Engrailed and Small Engrailed are moths of the family Geometridae. They are distributed across most of Europe. There is an on-going debate as to whether they make up one species, or whether E. crepuscularia actually refers only to the Small Engrailed, with the Engrailed proper being separable...
), a polyphagous geometer moth, also feed on Purple Loosestrife.
Cultivation, uses, and impact
It has been used as an astringentAstringent
An astringent substance is a chemical compound that tends to shrink or constrict body tissues, usually locally after topical medicinal application. The word "astringent" derives from Latin adstringere, meaning "to bind fast"...
medicinal herb to treat diarrhoea and dysentery
Dysentery
Dysentery is an inflammatory disorder of the intestine, especially of the colon, that results in severe diarrhea containing mucus and/or blood in the faeces with fever and abdominal pain. If left untreated, dysentery can be fatal.There are differences between dysentery and normal bloody diarrhoea...
; it is considered safe to use for all ages, including babies. It is also cultivated as an ornamental plant
Ornamental plant
Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as house plants, for cut flowers and specimen display...
in gardens. The flowers are showy and bright, and a number of cultivar
Cultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s have been selected for variation in flower colour, including 'Atropurpureum' with dark purple flowers, 'Brightness' with deep pink flowers, 'Happy' with red flowers on a short (60 cm) stem, 'Purple Spires' with purple flowers on a tall stem, and 'Roseum Superbum' with large pink flowers. It has also been introduced in many areas of North America by bee keepers, due to its abundunce of flowers which provide a large source of nectar.
As an invasive species
The purple loosestrife has been introduced into temperate New ZealandNew Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
and North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
where it is now widely naturalized and officially listed in some controlling agents. Infestations result in dramatic disruption in water flow in rivers and canals, and a sharp decline in biological diversity as native food and cover plant species, notably cattail
Typha
Typha is a genus of about eleven species of monocotyledonous flowering plants in the family Typhaceae. The genus has a largely Northern Hemisphere distribution, but is essentially cosmopolitan, being found in a variety of wetland habitats...
s, are completely crowded out, and the life cycles of organisms from waterfowl to amphibians to algae are affected.
A single plant may produce up to three million tiny seeds annually. Easily carried by wind and water, the seeds germinate in moist soils after overwintering. The plant can also sprout anew from pieces of root left in the soil or water. Once established, loosestrife stands are difficult and costly to remove by mechanical and chemical means.
Plants marketed under the name "European wand loosestrife" (L. virgatum) are the same species despite the different name. In some cases the plants sold are sterile, which is preferable.
In North America, purple loosestrife may be distinguished from similar native plants (e.g. fireweed
Fireweed
Epilobium angustifolium, commonly known as Fireweed , Great Willow-herb , or Rosebay Willowherb , is a perennial herbaceous plant in the willowherb family Onagraceae...
Epilobium angustifolium, blue vervain Verbena hastata, Liatris
Liatris
Liatris is a genus of ornamental plants in the Asteraceae family, native to North America, Mexico, and the Bahamas. These plants are used as a popular summer flowers for bouquets.They are perennials, surviving the winter in the form of corms....
Liatris spp., and spiraea
Spiraea
Spiraea , is a genus of about 80-100 species of shrubs in the family Rosaceae, subfamily Spiraeoideae. They are native to the temperate Northern Hemisphere, with the greatest diversity in eastern Asia....
(Spiraea douglasii) by its angular stalks which are square in outline, as well by it leaves, which are in pairs that alternate at right angle and are not serrated.
Biological control
Purple loosestrife provides a model of successful biological pest controlBiological pest control
Biological control of pests in agriculture is a method of controlling pests that relies on predation, parasitism, herbivory, or other natural mechanisms...
. Research began in 1985 and today the plant is managed well with a number of insects that feed on it. Five species of beetle
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
use purple loosestrife as their natural food source and they can do significant damage to the plant. The beetles used as biological control agents include two species of leaf beetle
Leaf beetle
Beetles in the family Chrysomelidae are commonly known as leaf beetles. This is a family of over 35,000 species in more than 2,500 genera, one of the largest and most commonly encountered of all beetle families....
: Galerucella calmariensis
Galerucella calmariensis
Galerucella calmariensis is a species of leaf beetle in the family Chrysomelidae. It is commonly known as the black-margined loosestrife beetle and is native to Europe and Asia where both adults and larvae feed on purple loosestrife...
and Galerucella pusilla, and three species of weevil
Weevil
A weevil is any beetle from the Curculionoidea superfamily. They are usually small, less than , and herbivorous. There are over 60,000 species in several families, mostly in the family Curculionidae...
: Hylobius transversovittatus
Hylobius transversovittatus
Hylobius transversovittatus is a species of weevil in the family Curculionidae. It is native to the Old World where both adults and larvae feed on purple loosestrife...
, Nanophyes breves, and Nanophyes marmoratus. Infestations of either of the Galerucella species is extremely effective in wiping out a stand of purple loosestrife, defoliating up to 100% of the plants in an area. The moth Ectropis crepuscularia is a pest species itself and unsuitable for biological control.
External links
- Invading Species.com Ontario Ministry of Natural Resources and Ontario Federation of Anglers and Hunters
- Species Profile- Purple Loosestrife (Lythrum salicaria), National Invasive Species Information Center, United States National Agricultural LibraryUnited States National Agricultural LibraryThe United States National Agricultural Library is one of the world's largest agricultural research libraries, and serves as a National Library of the United States and as the library of the United States Department of Agriculture...
. Lists general information and resources for Purple Loosestrife.