Impatiens glandulifera | |
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Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Asterids |
Order: | Ericales |
Family: | Balsaminaceae |
Genus: | Impatiens |
Species: | I. glandulifera |
Binomial name | |
Impatiens glandulifera | |
Synonyms [1] | |
List
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Impatiens glandulifera, Himalayan balsam, is a large annual plant native to the Himalayas. [2] Via human introduction it is now present across much of the Northern Hemisphere and is considered an invasive species in many areas. Uprooting or cutting the plants is an effective means of control.
In Europe, Himalayan balsam has been included since 2017 in the list of Invasive Alien Species of Union concern (the Union list). [3] This implies that the species cannot be imported, cultivated, transported, commercialized, planted, or intentionally released into the environment in the whole of the European Union. [4]
The common names Himalayan balsam and kiss-me-on-the-mountain refer to the plant's native Himalayan mountains. [5] Ornamental jewelweed refers to its cultivation as an ornamental plant.
The specific epithet glandulifera is a compound word from glándula meaning 'small gland', and ferre meaning 'to bear'.
It typically grows to 1 to 2 m (3.3 to 6.6 ft) high, with a soft green or red-tinged stem, and lanceolate leaves 5 to 23 cm (2.0 to 9.1 in) long. The crushed foliage has a strong musty smell. Below the leaf stems the plant has glands that produce a sticky, sweet-smelling, and edible nectar. The flowers are pink, with a hooded shape, 3 to 4 cm (1+1⁄4 to 1+1⁄2 in) tall and 2 cm (3⁄4 in) broad; the flower shape has been compared to a policeman's helmet.
After flowering between June and October, the plant forms seed pods 2 to 3 cm (3⁄4 to 1+1⁄4 in) long and 8 mm broad (1⁄4 in), which explode when disturbed, [6] scattering the seeds up to 7 metres (23 feet).
The green seed pods, seeds, young leaves and shoots are all edible. The flowers can be turned into a jam or parfait. [7]
The plant was rated in first place for per day nectar production per flower in a UK plants survey conducted by the AgriLand project which is supported by the UK Insect Pollinators Initiative. However, when number of flowers per floral unit, flower abundance, and phenology were taken into account, it dropped out of the top ten for most nectar per unit cover per year, as did all plants that placed in the top ten for per-day nectar production per flower, with the exception of common comfrey ( Symphytum officinale). [8]
Himalayan balsam is native to the Himalayas, specifically to the areas between Kashmir and Uttarakhand. In its native range it is usually found at altitudes between 2000 and 2500 m above sea level, although it has been reported at up to 4000 m above sea level. [9]
In Europe the plant was first introduced into the United Kingdom by John Forbes Royle, professor of medicine at King's College, London who became Superintendent of the Botanic Gardens, Saharanpur, India. [10] It has now become naturalized and widespread across riverbanks. [9] At present it can be found almost everywhere across the continent. [11] [12] [13]
In North America it has been found in the Canadian provinces of British Columbia, Manitoba, Ontario, Quebec, Nova Scotia, New Brunswick, Prince Edward Island and Newfoundland. [14] In the United States it is found on both the east and west coast, seemingly restricted to northern latitudes. [15]
In New Zealand it is sometimes found growing wild along riverbanks and wetlands. [16]
Himalayan balsam is sometimes cultivated for its flowers. It is now widely established in other parts of the world (such as the British Isles and North America), in some cases becoming a weed. Its aggressive seed dispersal, coupled with high nectar production which attracts pollinators, often allows it to out-compete native plants. Himalayan balsam also promotes river bank erosion due to the plant dying back over winter, leaving the bank unprotected from flooding. [17] Invasive Himalayan balsam can also adversely affect indigenous species by attracting pollinators (e.g. insects) at the expense of indigenous species. [18] It is considered a "prohibited noxious weed" under the Alberta Weed Control Act 2010. [19]
In the UK, the plant was first introduced in 1839, at the same time as giant hogweed and Japanese knotweed. [20] [21] These plants were all promoted at the time as having the virtues of "herculean proportions" and "splendid invasiveness" which meant that ordinary people could buy them for the cost of a packet of seeds to rival the expensive orchids grown in the greenhouses of the rich. Within ten years, however, Himalayan balsam had escaped from the confines of cultivation and begun to spread along the river systems of England. [20]
It has now spread across most of the UK, and some local wildlife trusts organise "balsam bashing" events to help control the plant. [20] However, a study by Hejda and Pyšek (2006) concluded that, in some circumstances, such efforts may cause more harm than good. Destroying riparian stands of Himalayan balsam can open up the habitat for more aggressive invasive plants such as Japanese knotweed and aid in seed dispersal by dropped seeds sticking to shoes. Riparian habitat is suboptimal for I. glandulifera, and spring or autumn flooding destroys seeds and plants. The research suggests that the best way to control the spread of riparian Himalayan balsam is to decrease eutrophication, thereby permitting the better-adapted local vegetation, that gets outgrown by the balsam on watercourses with high nutrient load, to rebound naturally. The researchers caution that their conclusions probably do not hold true for stands of the plant at forest edges and meadow habitats, where manual destruction is still the best approach.
The Bionic Control of Invasive Weeds project, in Wiesbaden, Germany, is trying to establish a self-sufficient means of conserving their local biodiversity by developing several food products made from the Himalayan balsam flowers. If all goes well, the project will have it financing its own eradication.
In August 2014, CABI released a rust fungus in Berkshire, Cornwall and Middlesex in the United Kingdom as part of field trials into the biological control of Himalayan balsam. [22]
Some research also suggests that I. glandulifera may exhibit allelopathy, which means that it excretes toxins that negatively affect neighboring plants, thus increasing its competitive advantage. [23]
The Royal Horticultural Society and the Centre for Ecology and Hydrology recommend that pulling and cutting is the main method of non-chemical control, and usually the most appropriate. [24] [25] Natural Resources Wales has used manual methods, such as pulling plants and using strimmers, to largely eradicate Himalayan balsam from reaches of the River Ystwyth. [26]
Himalayan Balsam is edible, but should be eaten in moderation as it contains oxalates [27]
Reynoutria japonica, synonyms Fallopia japonica and Polygonum cuspidatum, is a species of herbaceous perennial plant in the knotweed and buckwheat family Polygonaceae. Common names include Japanese knotweed and Asian knotweed. It is native to East Asia in Japan, China and Korea. In North America and Europe, the species has successfully established itself in numerous habitats, and is classified as a pest and invasive species in several countries. The plant is popular with beekeepers, and its young stems are edible, making it an increasingly popular foraged vegetable with a flavour described as lemony rhubarb.
Jacobaea vulgaris, syn. Senecio jacobaea, is a very common wild flower in the family Asteraceae that is native to northern Eurasia, usually in dry, open places, and has also been widely distributed as a weed elsewhere.
Impatiens is a genus of more than 1,000 species of flowering plants, widely distributed throughout the Northern Hemisphere and the tropics. Together with the genus Hydrocera, Impatiens make up the family Balsaminaceae.
Persicaria perfoliata is a species of flowering plant in the buckwheat family. Common names include mile-a-minute, devil's tail, giant climbing tearthumb, and Asiatic tearthumb. It is a trailing herbaceous annual vine with barbed stems and triangular leaves. It is native to most of temperate and tropical eastern Asia, occurring from eastern Russia and Japan in the north, and the range extending to the Philippines and India in the south.
Aegopodium podagraria, commonly called ground elder, is a species of flowering plant in the carrot family Apiaceae that grows in shady places. The name "ground elder" comes from the superficial similarity of its leaves and flowers to those of elder (Sambucus), which is not closely related. Other common names include herb gerard, bishop's weed, goutweed, gout wort, snow-in-the-mountain, English masterwort and wild masterwort. It is the type species of the genus Aegopodium. It is native to Europe and Asia, but has been introduced around the world as an ornamental plant, where it occasionally poses an ecological threat as an invasive exotic plant.
Cirsium vulgare, the spear thistle, bull thistle, or common thistle, is a species of the Asteraceae genus Cirsium, native throughout most of Europe, Western Asia, and northwestern Africa. It is also naturalised in North America, Africa, and Australia and is an invasive weed in several regions. It is the national flower of Scotland.
Heracleum mantegazzianum, commonly known as giant hogweed, is a monocarpic perennial herbaceous plant in the carrot family Apiaceae. H. mantegazzianum is also known as cartwheel-flower, giant cow parsley, giant cow parsnip, or hogsbane. In New Zealand, it is also sometimes called wild parsnip or wild rhubarb.
Euphorbia heterophylla, also known under the common names of Mexican fireplant, painted euphorbia, Japanese poinsettia, paintedleaf, painted spurge and milkweed, is a plant belonging to the Euphorbiaceae or spurge family.
Cirsium arvense is a perennial species of flowering plant in the family Asteraceae, native throughout Europe and western Asia, northern Africa and widely introduced elsewhere. The standard English name in its native area is creeping thistle. It is also commonly known as Canada thistle and field thistle.
Melilotus albus, known as honey clover, white melilot (UK), Bokhara clover (Australia), white sweetclover (US), and sweet clover, is a nitrogen-fixing legume in the family Fabaceae. Melilotus albus is considered a valuable honey plant and source of nectar and is often grown for forage. Its characteristic sweet odor, intensified by drying, is derived from coumarin.
Impatiens capensis, the orange jewelweed, common jewelweed, spotted jewelweed, jewelweed, spotted touch-me-not, or orange balsam, is an annual plant in the family Balsaminaceae that is native to North America. It is common in bottomland soils, ditches, and along creeks, often growing side by side with its less common relative, yellow jewelweed.
Miconia crenata, commonly called soapbush, clidemia or Koster's curse, is a perennial shrub. It is an invasive plant species in many tropical regions of the world, causing serious damage.
Acacia mearnsii, commonly known as black wattle, late black wattle or green wattle, is a species of flowering plant in the family Fabaceae and is endemic to south-eastern Australia. It is usually an erect tree with smooth bark, bipinnate leaves and spherical heads of fragrant pale yellow or cream-coloured flowers followed by black to reddish brown pods. In some other parts of the world, it is regarded as an invasive species.
A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is harmful to agricultural or horticultural crops, natural habitats or ecosystems, or humans or livestock. Most noxious weeds have been introduced into an ecosystem by ignorance, mismanagement, or accident. Some noxious weeds are native. Typically they are plants that grow aggressively, multiply quickly without natural controls, and display adverse effects through contact or ingestion. Noxious weeds are a large problem in many parts of the world, greatly affecting areas of agriculture, forest management, nature reserves, parks and other open space.
Impatiens balsamina, commonly known as balsam, garden balsam, rose balsam, touch-me-not or spotted snapweed, is a species of plant native to India and Myanmar.
Angelica sylvestris or wild angelica is a species of flowering plant, native to Europe and central Asia. An annual or short-lived perennial growing to a maximum of 2.5 metres (8.2 ft), it has erect purplish stems and rounded umbels of minuscule white or pale pink flowers in late summer.
Impatiens pallida, with the common names pale jewelweed, pale touch-me-not, or yellow jewelweed, is a flowering annual plant in the family Balsaminaceae native to Canada and the United States. It grows in moist to wet soils, generally alongside the closely related Impatiens capensis, producing flowers from midsummer through fall.
Lantana camara is a species of flowering plant within the verbena family (Verbenaceae), native to the American tropics. It is a very adaptable species, which can inhabit a wide variety of ecosystems; once it has been introduced into a habitat it spreads rapidly; between 45ºN and 45ºS and less than 1,400 metres in altitude.
Impatiens parviflora is a species of annual herbaceous plants in the family Balsaminaceae, native to some areas of Eurasia, naturalized elsewhere and found in damp shady places. Impatiens parviflora can grow in sandy, loamy, and clay soils and prefers moist soil.
An escaped plant is a cultivated plant that has escaped from agriculture, forestry or garden cultivation and has become naturalized in the wild. Usually not native to an area, escaped plants may become invasive. Therefore, escaped plants are the subject of research in invasion biology.
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