Identifying Himalayan Balsam

Himalayan balsam saplings begin to appear in March and as adult plants can reach a height of 3m. The plants have pinky-red hollow jointed stems and shiny green lance shaped leaves. The flowers range from purplish-pink to almost white in colour and are slipper shaped, appearing on long stalks between June and October.

The flowers are followed by seedpods that explode dispersing the seeds between late July and October.

You can take a look at our Himalayan Balsam infographic that shows the anatomy of the plant to help you identify it.
Alternatively, please see the Himalayan Balsam Gallery for more images to help you identify the plant.

If you still aren’t sure, you can download the free iNaturalist app (apple and android) which enables you to take a photo of the plant and it will be identified. You are then able to share the location.

#PullSnapStomp

Find out more about how you can help clear this invasive plant when you’re out and about.

Close up of Himalayan Balsam by Erica Martin

HIMALAYAN BALSAM (Impatiens glandulifera)

How to Identify Himalayan Balsam
(Edible)

Common names
Himalayan Balsam, Indian Balsam, Bobby Tops, Copper Tops, Gnome’s Hatstand, Ornamental Jewelweed, Policeman’s Helmet, Kiss-me-on-the-Mountain
Botanical name
Impatiens glandulifera
Meaning of botanical name
Impatiens is from the Latin for impatient, referring to how the seed pods burst open. Glandulifera means to have have flowers with glands
Known hazards
This plants is a non-native invasive and eradication programmes are in place in many parts of the UK. Some people have displayed allergies to Himalayan Balsam’s pollen.

Could be confused with
The flowers are very distinctive, so it would be difficult to confuse with other species
Food plant of
Very popular with pollinators. However, the big showy flowers distract from native species.

Range and distribution
Invasive and established across the globe

Habitat
Most commonly found along waterways, but can grow away from water. It was introduced to the UK in 1839 as garden plant

Physical characteristics
Tall stems reaching up to 2m in height. The stalk is has a reddish tinge. Flowers are pink and shaped like helmets, and the seed pods explode when gently touched.
Edible use
The seedings, young shoots, leaves, flowers and seeds are all edible. The seeds give a nice crunch and texture to salads, while the flowers and young shoots can be made into jams

Miscellaneous
It is a relative of the Busy Lizzie. The hollow stalks can be used as a straw.
Tips and Observations
When harvesting the seeds, carefully place a carrier bag over the tops of the plants and close the neck of the bag with you hand. This action alone should be enough to cause the seed heads to explode and catch all the seeds. Remember to tip the bag right way up before removing your hand.

Himalayan Balsam

What are the issues?

Himalayan balsam (Impatiens glandulifera) is an introduced summer annual that has naturalised in the UK, mainly along riverbanks and ditches. It prefers moist soils but will grow pretty much anywhere. Plants can grow up to 3m tall, making this the tallest annual species growing wild in the UK.

Himalayan balsam flowers

A native of the Western Himalaya, it was introduced in 1839 to Kew Gardens as a greenhouse exotic. It escaped into the wild and is now recorded throughout the UK, particularly along the banks of watercourses. It is locally common in Wales and England. It is less frequent in the Highlands of Scotland and western parts of Northern Ireland, but it is rapidly increasing its range. It grows quickly, spreads easily, readily colonises new areas and out-competes other vegetation. When the plants die back each winter they leave large areas of bare ground that can be sensitive to erosion.

Identifying features to look out for

  • The hollow, succulent stems are purple tinged and smooth.
  • The serrated, pointed leaves are arranged in pairs, or three to a node; they are mid green with a pinkish mid-rib and about 12 to 16cm long.
  • Flowers vary from pale pink to purple and appear from June to October. Their shape resembles an English policeman’s helmet (which is their common name in some parts of the country). They produce copious amounts of nectar and are thought to draw pollinating insects in preference to native plants, thus reducing pollination of the latter.

    Exploded Himalayan balsam seed pod

  • A single plant can set about 800 seeds, 12 to 14 weeks after flowering. The mature seed capsules react to the slightest disturbance, causing the five segments to split along their length, then curl up and twist explosively, projecting the contents up to 7m away. The black, round seeds are about 2 to 3mm across and remain viable in the soil’s seedbank for about 2 years. They are buoyant and can travel long distances along waterways to infest new areas, even germinating under water.

How can it be controlled?

Mechanical control

The plant is easy to cut before flowering, either by hand or machine, provided there is adequate access. Plants should be cut to ground level before the end of June and before flowering. Earlier cutting results in rapid regrowth of new stems that will flower and set seed, whereas later cutting risks spreading viable seeds that can germinate next growing season. Cutting is only effective if made very close to the lowest nodes, near ground level. Regular mowing will also control plants even if the cutting level is above the lowest node, provided the frequency is sufficient to prevent the formation of flowers and seeds. Grazing by cattle and sheep can also be an effective cutting regime and should begin in mid-April, continuing throughout the growing season. Small infestations can be controlled by hand pulling, as the plant is shallow rooted. However, this can be quite labour intensive. The seedbank lasts for approximately 18 months, so two years’ control should eradicate the plant if there is no further reintroduction to the site from upstream seeds.

Chemical control

It can be controlled by spraying the foliage with glyphosate. The plants should be sprayed in the spring before flowering but late enough to ensure that germinating seedlings have grown up sufficiently to adequately absorb the herbicide. Small infestations and individual plants can be controlled by using glyphosate in a weed wiper. This has the advantage of minimising herbicide effects on non-target species. The herbicide 2,4-D amine controls many broadleaved annual weeds and can be used on Himalayan balsam. It is a selective herbicide that will not kill grasses, which can help to keep banks stabilised, making it useful sometimes to use instead of glyphosate.

Contact Phlorum

We can help solve your Himalayan balsam problem. We can be contracted directly to carry out the site works outlined above, or employed in a consultancy role to map areas of invasion and provide detailed management plans to eradicate the problem.

Please contact us for more details on our services and to discuss your specific needs.

Further Information

  • Non-Native Species Secretariat page on Himalayan balsam
  • Plantlife page on Himalayan balsam

Invasive flower, policeman’s helmet, beautiful, but blacklisted

The seeds of Impatiens glandulifera, commonly known as Policeman’s Helmet, grow very quickly, as much as 4 centimetres per day. They can grow to a height of 1.5 to 3 meters, and have attractive purple, pink or white flowers. Many people find the flowers pretty, until this invasive plant behaves the way it is defined.

The flowers mature into seed pods that spontaneously explode, spreading thousands of seeds in a 6-7 meter radius. This creates a colony of rapidly growing plants that often outcompete other species. This ability has given the Policeman’s Helmet a high ranking on Norway’s Black List of invasive plants.

Very adaptable

Policeman’s Helmet is very good at adapting to its surroundings. NTNU biologist Kamal Prasad Acharya is studying how plants like Policeman’s Helmet plants adapt to new environs, and how they propagate. He has collected seeds from six different populations around Europe via a research network of biologists. The seeds come from France, Belgium, Germany, Sweden (Lund and Stockholm) and Norway (Trøndelag).

The populations from the different geographical areas differ in the height they reach and the time between flowering and the maturation of the seed pods. Acharya has cultivated seeds from the different populations so he can study these differences.

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“They grow differently, and it turns out that they adapt to their environment very quickly,” he explains.

Fast reproduction in the north

“I have grown two generations of these plants in controlled surroundings in the university’s greenhouse. I have observed clear differences between the different populations, which is usually unexpected if the plants don’t have any genetically adapted differences,” Acharya says.

The further north the populations come from, the faster they grow to begin with and the faster they begin to flower, whereas the populations from further south are in flower for a shorter amount of time.

“The plants from the north have a shorter growth season and have to complete their life cycle more quickly. This indicates that the species has adapted to varying climatic and geographical conditions quickly, since they haven’t grown in the different areas for very long,” he explains.

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A long migration

Like many invasive species such as dandelions and lupines, Policeman’s Helmet was originally imported as a decorative plant. It is originally from the western Himalays, where it grows as high as 4000 metres. It can also be found in the Kashmir area of India, and it was here the Europeans discovered it. The British botanist John F. Royle collected seeds from India that he sent home to Great Britain. This was how Policeman’s Helmet arrived in Europe in 1839.

Policeman’s Helmet arrived in Norway via the biologists Frederik Christian Schübeler in the 1870s. Schübeler was a professor at the university in Kristiania and was in charge of the botanical gardens and museum. He experimented with plants, and sent curious gardeners all over the country to collect plant samples and seeds to cultivate. Among these species was Policeman’s Helmet.

Spreads in many ways

In Norway, most of the plants are found around Oslo fjord and in central Norway, especially near Trondheim fjord. The northernmost population was found in Nordreisa in Troms. But Schübeler and the exploding seed pods can’t take sole credit for spreading Policeman’s Helmet around the country. It spreads itself in several ways.

Many of the early observations were near mills, so it was assumed that the seeds had come to Norway along with imported grains. The seeds can also travel long distances in the water, in streams or roadside ditches. They also spread through the transport of dirt or garden waste. Additionally, ants have been found to transport the seeds and thus propagate the plant.

Proof of the existence of several varieties has been found. These varieties may have been introduced to the same place at several different times. This is even worse than a simple invasive species.

“Several introductions increase the genetic diversity that contribute to creating even more adaptable populations,” Acharya says.

Policeman’s Helmet – July 2016 Weed of the Month

In 1839, seeds of Impatiens glandulifera were sent from their native home in western Himalaya to the Royal Botanic Gardens in Kew, England. Within 15 years, populations had escaped and naturalized into the English countryside. By the 1900’s, the plant was widespread throughout England and Ireland. Today, it is considered one of Great Britain’s “Top 20” Alien Plants because of its abundance and distribution.

Policeman’s helmet (Impatiens glandulifera) growing along a river in England in August 2015. Photo by Sasha Shaw.

Policeman’s helmet, also known as Himalayan balsam or poor man’s orchid, continues to move into new parts of the world with the help of gardeners attracted by the pretty flowers and the naturalistic way it self-seeds in the garden and beyond. It is now naturalized in 31 countries on three continents (Europe, North America and Asia) and is rapidly expanding its range especially in Europe, Eastern Asia and North America.

Dense infestation of policeman’s helmet, also called Himalayan balsam, in the United Kingdom.

In our region, policeman’s helmet is well-established in parts of western Washington and the lower Fraser Valley of British Columbia. In King County, we are fighting infestations in several areas including several creeks in Bellevue, Peasley Canyon in Auburn, Issaquah Creek in Issaquah, Thornton Creek and Carkeek Park in Seattle, and the Mountain View Road area of Duvall, among others.

Policeman’s helmet infestation on a creek in King County, Washington.

Although this plant is only an annual, it can reach ten feet tall in wet, shaded areas, shorter in dry, sunny spots.

Policeman’s helmet (Impatiens glandulifera) gets very tall in areas with lots of water.

Pretty pink-purple to white flowers are present from June to October (shaded plants flower later) and seeds set within 13 weeks after flowering. When the seed capsules mature, they split open and eject around 800 seeds as far as 20 feet away. The seeds travel along waterways, can germinate under water and are viable in the soil for about two years.

Policeman’s helmet (Impatiens glandulifera) flowers are pink to purple. The seed pods burst open when touched and eject seeds far from the parent plant.

Because of its shallow root system, policeman’s helmet can be effectively and easily pulled, if care is taken to remove the whole root. However, its stems will root at the nodes and re-grow if left on the ground.

Policeman’s helmet has shallow roots and can be hand-pulled.

Large patches of policeman’s helmet can be quite dense and take many hours of work to remove.

Pulled stems should be crushed and dried or piled on tarps to compost. At least two years of follow-up monitoring is recommended to catch new plants germinating from the seeds in the soil. It’s critical to recheck the same area late in the summer or early fall to catch plants that flower later or were overlooked the first time through. Policeman’s helmet is really good at hiding among the salmonberry or blackberry bushes and can continue flowering into October, especially in shaded areas. A few overlooked plants can undo all your hard work.

Policeman’s helmet can continue flowering as late as October and a single flowering plant can ruin all your hard work removing it.

No longer legal to sell in Washington State, policeman’s helmet remains a favorite trading plant among gardeners, who often find themselves with numerous volunteers to share with their friends and neighbors (not a nice thing to do to your friends). Policeman’s helmet is now on the state’s quarantine list of prohibited plants so garden sales should no longer have the species in their inventory.

Make sure to look for policeman’s helmet plant hitchhiking in pots of other plants purchased at garden sales.

Besides showing up near gardens, policeman’s helmet escapes into moist lowland forests, stream sides, and roadside thickets. This plant is a strong competitor and can reduce the fitness of native plant species and eventually replaces them in invaded sites. Left alone, this plant will continue to spread into riparian areas and to push out beneficial native plants.

Although quite distinctive when it flowers, policeman’s helmet (Impatiens glandulifera) can be confused before it blooms with another weedy member of the touch-me-not family called spotted jewelweed (Impatiens capensis). Spotted jewelweed flowers are orange with reddish spots, scalloped leaf edges (instead of the regular, small teeth on policeman’s helmet leaf edges), and is generally only a few feet tall. Spotted jewelweed is native to the eastern United States and was introduced here by gardeners and others beginning around 1950.

Spotted jewelweed (Impatiens capensis) in King County, Washington

Spotted jewelweed (Impatiens capensis) on the left, policeman’s helmet (Impatiens glandulifera) on the right.

Similar to policeman’s helmet, spotted jewelweed can be quite weedy, especially in disturbed stream sides and other moist areas. However, policeman’s helmet is much taller and dominates other plants much more than spotted jewelweed. Spotted jewelweed is a Weed of Concern in King County but is not a state noxious weed in Washington.

Also, spotted jewelweed should not be removed without first getting a positive identification. There is a rare native found locally called spurless jewelweed (Impatiens ecornuta) that closely resembles spotted jewelweed. It can only be distinguished when it is in flower, and that can be tricky due to the presence of hybrids between the two species. Native spurless jewelweed flowers don’t have spurs and are not spotted.

Policeman’s helmet is a state noxious weed that is regulated in King County, so property owners and public agencies are required to remove it from their property. It is easiest to remove policeman’s helmet when it is in bloom, but before it seeds, since it is easy to find and easy to pull. Once policeman’s helmet has mature seeds on it, it is very hard to pull without spreading the seeds. The seeds are ejected from the pods with amazing force (this is fascinating to experience, but please put a bag around the seed pods before trying it!). Also, stems will re-root and flower again if left on moist soil or piled up. Crush the stems completely before leaving them to rot, preferably on a tarp or paved area. Bagging and discarding the plants is another option.

Piles of policeman’s helmet will start to re-grow unless they are crushed and composted well.

Please report infestations to us so we can survey the surrounding areas for new patches. If you have questions or would like more information about this or other noxious weeds in King County, Washington feel free to contact us by email or visit our website www.kingcounty.gov/weeds.

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Categories: Tips, Weed Identification, Weed of the Month

Tags: impatiens, King County, noxious weeds, plant identification, policeman’s helmet, Weed Control, weeds

Balsam

BALSAM

bol’-sam (basam, besem; hedusmata; thumiamata):

Is usually “spices” but in the Revised Version, margin (Song of Solomon 5:1,13; 6:2) is rendered as “balsam.” It was an ingredient in the anointing oil of the priests (Exodus 25:6; 35:28). The Queen of Sheba brought it as a present to Solomon (1 Kings 10:2) in large quantity (1 Kings 10:10) and of a finer quality (2 Chronicles 9:9) than that brought as a regular tribute by other visitors (1 Kings 10:25). In the later monarchy Hezekiah had a treasure of this perfume (2 Chronicles 32:27) which he displayed to his Babylonian visitors (Isaiah 39:2); and after the captivity the priests kept a store of it in the temple (1 Chronicles 9:30). According to Ezekiel the Syrians imported it from Sheba (Ezekiel 27:22). There is a tradition preserved in Josephus (Ant., VIII, vi, 6) that the Queen of Sheba brought roots of the plant to Solomon, who grew them in a garden of spices at Jericho, probably derived from the references to such a garden in Song of Solomon 5:1,13; 6:2. This may be the source of the statements of Strabo, Trogus and Pliny quoted above (see BALM). It was probably the same substance as the BALM described above, but from the reference in Exodus 30:7; 35:8, it may have been used as a generic name for fragrant resins. The root from which the word is derived signifies “to be fragrant,” and fragrant balsams or resins are known in modern Arabic as bahasan. The trees called in 2 Samuel 5:23,24 (Revised Version, margin) “balsam-trees” were certainly not those which yielded this substance, for there are none in the Shepehlah but there are both mulberry trees and terebinths in the district between Rephaim and Gezer. When used as a perfume the name basam seems to have been adopted, but as a medicinal remedy it is called tsori.

Alex. Macalister

Balsam Plant Information: Tips For Growing Balsam Plants

Balsam requires 60 to 70 days from sowing to produce flowers, so an early start is essential. Learn how to grow balsam and enjoy these lovely colorful flowers through the end of the season. Try growing Balsam plants from seed if you have a long growing season, or pick them up at your favorite nursery. Balsam plant care is trouble-free due to its resistance to many common garden pests. It may be plagued by soil nematodes, powdery mildew or Oedema, but these problems are relatively infrequent.

Balsam Plant Information

Balsminaceae impatiens is a common sun to partial shade flowering annual. It is easy to grow and widely available at nurseries and garden centers. Impatiens balsamina is known by the common name balsam or by the umbrella moniker of impatiens, which covers a wide variety of forms and tones. Balsam may also be found as “Rose Balsam.”

The flowers bear double petals and come in an array of colors but are partially hidden by large

attractive leaves with pronounced veins. Balsams come in white, red, orange, yellow, violet, and pink. These flowers resemble mini roses or camellias with the thickly spaced petals and tones.

Some fun balsam plant information is found in another of its names: touch-me-not. The name is owing to the end of season pods which form and burst at the slightest touch.

How to Grow Balsam

Start plants indoors for an earlier color show. You may direct sow in warmer climates where soils warm up early in the spring, but the majority of gardeners will find that sowing in flats at least 8 weeks before the date of the last frost will yield the best plants.

Cover the seeds with just a dusting of soil and keep moist. In garden flats, cover the top of the soil with plastic to encourage germination and keep in moisture. Expect germination when growing balsam plants from seed in approximately 10 to 15 days.

Young balsam plant care should include a time release fertilizer at transplant, when plants are at least 2 inches tall and have a good root base.

Caring for Balsam

Balsam needs moist, well-drained soil and performs best in partial shade locations. Amend the soil with compost and break up clods before transplanting young balsam. Spacing is 12 to 18 inches apart.

Water the plants from below to help prevent powdery mildew. A soaker hose or drip line system will assist with this method of watering. The plants will need supplemental watering at least once a week in the dry months. More frequent watering is necessary when caring for balsam in containers and hanging baskets.

Collect the seed pod carefully at the end of the season for another year of rose balsam beauty in your garden. Let the pod dry and keep in a closed plastic bag or jar in a dark, cool area of the home until spring.

Learn About Balsam

Downy Mildew: This fungus causes whitish grey patches on the undersides and eventually both sides of the leaves. Burpee Recommends: Rotate crops with plants in a different family. Avoid overhead watering. Provide adequate air circulation, do not overcrowd plants. Do not work around plants when they are wet.

Edema (Oedema): Leaves become distorted due to excess moisture in the soil. Plants absorb more water than they can use. Burpee Recommends: Do not overwater plants, keep the soil moist but not wet. If drainage is poor add compost or peat moss to improve drainage.

Powdery Mildew: This fungus disease occurs on the top of the leaves in humid weather conditions. The leaves appear to have a whitish or greyish surface and may curl. Burpee Recommends: Avoid powdery mildew by providing good air circulation for the plants by good spacing and pruning. Contact your Cooperative Extension Service for fungicide recommendations.

Root Knot Nematodes: Microscopic worm-like pests that cause swellings (galls) to form on roots. Plants may wilt or appear stunted. This is a serious problem in many Southern states. Burpee Recommends: Do not plant into infested soil. Grow resistant varieties. Try planting ‘Nema-Gone’ marigolds around your plants.

Common Pest and Cultural Problems

Aphids: Greenish, red, black or peach colored sucking insects can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps who feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.

Cucumber Beetles: Beetles may be spotted, striped or banded and can be very harmful. Beetles are usually ¼ to ½ inch in size. Beetles start feeding as soon as they hatch and can kill or slow the growth of the plants. Beetle larva can also bore through the roots of the plants. Beetles can also transmit diseases from plant to plant. Burpee Recommends: Knock off adults into a jar of soapy water and destroy them. Spade the soil to destroy dormant beetles before you plant. Use a row cover to prevent adults from feeding on young plants. Consult your Cooperative Extension Service for other insecticide recommendations.

Tarnished Plant Bug: These insects cause distorted leaves and flower buds. The adults are about ¼ inch long, oval shaped and flat. They are greenish brown with reddish brown markings on their wings. There is a small but distinct yellow tipped triangle in the center of the back behind the head. Burpee Recommends: Introduce beneficial insects to your garden. Traps are available. Try insecticidal soap.

medicinal herbsRose BalsamImpatiens balsamina

Herb: Rose Balsam

Latin name: Impatiens balsamina

Family: Balsaminaceae (Touch-me-not Family)

Medicinal use of Rose Balsam:

The plant is cathartic, diuretic and emetic. It is used in the treatment of pains in the joints. The leaf juice is used as a treatment against warts. The flowers are cooling, mucilaginous and tonic. They are useful when applied to burns and scalds. The juice of the flowers is used to treat snakebites. The flowers, and their alcoholic extract, possess marked antibiotic activity against some pathogenic fungi and bacteria. The seed is expectorant and has been used in the treatment of cancer. The powdered seeds are given to women during labour in order to provide strength.

Description of the plant:

Plant:

Annual

Height:

60 cm
(2 feet)

Habitat of the herb:

Waste places in and around villages.

Edible parts of Rose Balsam:

Leaves and young shoots – cooked. Seed – raw or cooked. They are difficult to collect in quantity, mainly because of their exploding seed capsules which scatter the ripe seed at the slightest touch.

Other uses of the herb:

A dye is obtained from the plant. The prepared juice has been used for dyeing fingers and toenails red. The seed contains 27% of a viscous oil, though the report does not mention if this oil is utilised for any purpose.

Propagation of Rose Balsam:

Seed – sow spring in a greenhouse. When they are large enough to handle, prick the seedlings out into individual pots and plant them out in the summer.

Cultivation of the herb:

Waste places in and around villages.

Known hazards of Impatiens balsamina:

Regular ingestion of large quantities of these plants can be dangerous due to their high mineral content. This report, which seems nonsensical, might refer to calcium oxalate. This mineral is found in I. capensis and so is probably also in other members of the genus. It can be harmful raw but is destroyed by thoroughly cooking or drying the plant. People with a tendency to rheumatism, arthritis, gout, kidney stones and hyperacidity should take especial caution if including this plant in their diet.
Plant information taken from the Plants For A Future.

This video shows how to remove Himalayan balsam late in the season, in cases where it is flowering and been allowed to set seed.

The plant is popular with bee keepers as a late source of nectar, but advice from the British Beekeepers Association is it should only be kept in gardens and cut before it sets seed.

Tom Morgan from Wiltshire Wildlife Trust advises exactly how to remove the plant and prevent seed dispersal.

Video Transcript: How to pull late season (flowering) Himalayan balsam

We are here on the river Nadder just outside Salisbury with a rather impressive infestation of Himalayan balsam.

As you can see, himalayan balsam can achieve quite a height (3 m) allowing it to disperse its seed by exploding seed pods.

By growing to such a height and exploding it can disperse its seeds maybe 3-5 m from the original plant, which can cast into the river and carried on by the flow. Wherever the water settles in slower areas or floods, new infestations will start.

It is quite late in the summer (August), so unfortunately the seed heads are very well developed and ripe. Potentially pulling up the plant will disturb the seed pods, causing them to be released into the river.

How to pull flowering Himalayan balsam:

  • remove himalayan balsam seed pods
  • collect the seeds in bags
  • dispose of them at a later date

It is just a simple process of being very careful with the plant and trying to pull it over and taking the seed heads off.

Once we have removed all of the seed heads from the whole plant we can just pull it up from the base and crush it up.

So as you can see for such a large plant, it has a very small root ball. This means it is really easy to pull up and great for a task for volunteers (involved in Himalayan picking parties).

Once you have pulled it up, snap it in half, where you get a really satisfying crunch. Crush it up a couple of times. Then we pile it up on the bank in discrete piles so they mulch.

It is important to crush them up and stick them in a pile where they have less chance of regrowing and mulch down into nothing as they are very almost celery-like at the bottom, and very high water content plants and mulch down very very quickly.

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Himalayan balsam Impatiens glandulifera

A non-native invasive plant.

The largest annual plant in Britain, growing up to 2.5m high from seed in a single season. Himalayan balsam spreads quickly as it can project its seeds up to four metres. Many seeds drop into the water and contaminate land and riverbanks downstream, but the explosive nature of its seed release means it can spread upstream too.

It has large ‘policeman’s helmet’ pink-purple flowers. Leaves have small red teeth at the edge and are in whorls of 3 or opposite. The stem is reddish.

Habitat

Commonly found along riverbanks and streams, around ponds and lakes, in wet woodlands and in ditches and damp meadows.

What’s the problem?

It spreads quickly and forms dense thickets, altering the ecological balance and character of wetland habitats. Many seeds drop into the water and contaminate land and riverbanks downstream, but the explosive nature of its seed release (seeds can be projected up to four meters away) means it can spread upstream too. It produces a lot of pollen over a prolonged season and is attractive to pollinating insects. There is concern that its presence may therefore result in decreased pollination for other native plants.

This species is listed on Schedule 9 of the Wildlife and Countryside Act in England and Wales therefore, it is also an offence to plant or otherwise cause to grow these species in the wild.

Removing Himalayan balsam

Indian balsam needs dealing with before it sets seed. If control is undertaken early enough to prevent flowering (and if this is achieved before seed has set) then eradication is possible in two or three years. We recommend that the plants, which are shallow-rooted, should be pulled out and disposed of by composting carefully, or by burning if seeds are present. If this is done on a regular basis and the plant is not allowed to set seed, it will eventually die out. Regular strimming of larger areas is also an option, as long as it is done often enough to prevent flowering.

Did you know?

Introduced in 1839, it was first cultivated as a greenhouse annual by gardeners.

Local names include Nuns and Jumping Jack, as well as Policeman’s Helmet, Bobby Tops and Gnome’s Hatstand which refer to the fact that the flower is decidedly hat-shaped. Himalayan Balsam and Kiss-me-on-the-mountain arise from the fact that the plant originates in the Himalayan mountains.

The genus name Impatiens, means “impatient”, and refers to its method of seed dispersal. The species name glandulifera comes from the Latin words glandis meaning ‘gland’, and ferre meaning ‘to bear’, referring to plant bearing glands.

Touch-me-not Balsam pods explode without warning when they’re ready to disperse their seeds. The seed pods also happen to be the Netted Carpet Moth larva’s favorite food. So what happens when this hungry caterpillar eats from a pod that’s ready to pop? This BBC clip from The Lake District: A Wild Year, narrated by Bernard Cribbins, captures their challenge.

Some additional background from NationalTrust.org.uk:

Research has shown that this moth relies totally on touch-me-not balsam. This small delicate plant with yellow flowers is the only native species of balsam in the UK, but many invasive balsams are aggressively wiping this plant out. This means that the population of the netted carpet moth plummeted to near extinction in the 1980s and 1990s and has only recently begun to recover. The perfectly camouflaged larvae of this moth feed exclusively on the plant.

Numbers of this moth are returning thanks to a partnership of many organisations. Here in the south Lakes the National Trust ranger team has been working hard to play their part in the return of this species to many areas. By introducing cows to the favoured areas of the moth, research has shown that more aggressive plants such as Himalayan balsam are kept at bay, allowing the touch-me-not to flourish. Our rangers have also been “pulling up” invasive species such as yellow balsam to make space for touch-me-not to return.

Watch more exploding plants disperse their seeds with high pressure bursts.

Then watch more videos about seed dispersal, including this humidity-powered seed drills that itself into the ground.

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