Grass-poly or Lythrum hyssopifolia was in the news the other day:
“A rare plant that vanished from a farmland pond more than a century ago has ‘come back from the dead’. Delighted conservationists found the pinkish-flowered species, known as grass-poly, growing in rural Norfolk by a neglected waterhole. The stunning plant reappeared after seeds submerged in the mud were disturbed during work to restore the pond.“
Thanks are due for the information found on various websites (mainly Wikipedia, R.B.G. Kew Plants of the World Online, etc) and books for which I provide links. There is colour coding for easy reading. Blue and yellow for general interest, green for wildlife and other uses and pink where there are medicinal uses or warnings. All pictures are by Matt Summers otherwise mentioned.
Lets have a look at this plant and the rest of its family!
Contents:
The Lythraceae or Loosestrife family
Lythrum hyssopifolia or Grass-poly
L. junceum or False Grass-poly
L. portula or Water-purslane
L. salicaria or Purple-loosestrife
The Lythraceae or Loosestrife family
The Lythraceae family has 32 genera, but in the B.I. there is only one representing genus, Lythrum, which is Family 72 in Stace between the Geraniaceae and the Onagraceae.
There are only 4 species of Lythrum in the B.I. and 3 of those are native.
Lythrum hyssopifolia or Grass-poly
An annual herb of disturbed ground which is flooded in winter, including hollows and ruts in arable fields, scrapes in gravel-pits, wet shores of lakes and damp pastures disturbed in winter by wildfowl. It sometimes occurs as a casual from seeds introduced with grain or from other sources. The seeds have considerable longevity in the soil.
It is rare in the United Kingdom, extremely local in S. England and Channel Islands according to Stace.
An archaeophyte in Britain and the Channel Islands and a neophyte in Ireland.
The grass-poly (and presumably the other species) are said to have similar therapeutic properties to Purple loosestrife (see below).
L. junceum or False Grass-poly (Neophyte)
The grass-poly is said to have similar therapeutic properties to Purple loosestrife
L. portula or Water-purslane
An annual herb of acidic or calcium-deficient silty soils at the muddy margins of pools and in temporarily flooded habitats such as rutted tracks, woodland rides, heathland pools and the draw-down zone of reservoirs. Very occasionally it will grow submerged in up to 1 m depth of water. It avoids the most acidic and nutrient-poor soils and is rarely found over peat.
According to PFAF the leaves can be eaten raw or cooked.
Purple loosestrife in its typical, damp, native habitat and close-up with Painted Lady Butterfly (pictures by Matt Summers)
L. salicaria or Purple loosestrife
This is the best know Lythrum as well as the most handsome one!
A perennial herb growing on the margins of slow-flowing rivers, canals, lakes, flooded gravel-pits, in tall-herb fens and willow-carr. It thrives in permanently wet, or periodically inundated, fertile soils and tends to avoid acidic conditions.
This plant grew abundantly in my former neighbour’s allotment. Despite being on heavy clay soil and not near any water where I usually seen it, it always attracted plenty of bees!
I found this interesting: 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 flowers are visited by many types of insects, and can be characterized by a generalized pollination syndrome.
It was introduced into temperate New Zealand and North America where it is now widely naturalised and causing problems!
It is a wonderful plant to enhance wildlife gardens and is particularly associated with damp, poorly drained locations such as marshes, bogs and watersides.
The flowers are pollinated by long-tongued insects, including bees and butterflies.
A number of insects use Lythrum salicaria as a food resource.
The black-margined loosestrife beetle Galerucella calmariensis and the golden loosestrife beetle Galerucella pusilla feed on the leaves. The loosestrife root weevil Hylobius transversovittatus and the loosestrife flower weevil Nanophyes marmoratus often stop the plants to produce seeds.
Caterpillars of the engrailed moth (Ectropis crepuscularia), a polyphagous geometer moth, also feed on Purple loosestrife.
It has been introduced in many areas of North America by bee keepers, due to its abundance of flowers which provide a large source of nectar.
It is cultivated as an ornamental plant in gardens. The flowers are showy and bright, and a number of cultivars 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
- ‘Roseum Superbum’ with large pink flowers.
The cultivars ‘Blush’ with blush-pink flowers, and ‘Feuerkerze’ with rose-red flowers have gained the Royal Horticultural Society‘s Award of Garden Merit.
The plant is hardly used in Britain according to Julian Barker but is much better known across the Channel for its actions which are:
Astringent, haemostatic, anti-inflammatory and antimicrobial.
Some uses are: Intestinal colic, diarrhoea, leucorrhoea, menorrhagia, tonsillitis, bacterial throat infections and will arrest nose bleeds.