Common Toadflax, Linaria vulgaris

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Common Toadflax, Linaria vulgaris

Earlier in the month I wrote about Devil’s-bit Scabious, Succisa pratensis. Another British wild flower that gives a splash of late colour is Common Toadflax, Linaria vulgaris. Here in Norfolk, its yellow flowers light up grassy road verges, it also flowers along grassy rides in Breckland and I grow it in our garden.

Linaria vulgaris is a hardy perennial with stems up to 90cm (36 inches) tall, with narrow, linear bluish-green leaves all round the stem, topped with lovely yellow two-lipped flowers, like a Snapdragon (Antirrhinum majus) but with a long spur at the back. The flowers have a darker yellow or even yellow-orange centre, where the lips meet. (See the Wildflower Finder website for lots of lovely photos.) Common Toadflax can come into flower as early as June and its flowers can usually be found into late October.

Common Toadflax is widely distributed and common in England, Wales and lowland Scotland, but scarcer in Ireland. It grows in open grassy places, on stony and waste ground, in hedge banks, on road verges and railway embankments and on cultivated land, especially on calcareous soils. It is a native of temperate areas of Europe and Asia as far as China, including the British Isles (note 1).

It has been introduced into Japan, North America (Canada and United States), Australia, Chile and South Africa. The CABI Invasive Species Compendium lists countries and states where the plant is found, along with the dates and impacts of introduction (note 2). Where introduced, Linaria vulgaris can be an agricultural weed, especially in Alberta in Canada. It can also compete with native vegetation, as in parts of the United States, including Yellowstone National Park. On the plus side, its roots can help to stabilise soil.

Common Toadflax has creeping roots bearing adventitious buds and over time plants can form dense mats. They can also reproduce by seed (note 3).

Like Ribwort Plantain, Weasel’s-Snout and Sharp-leaved Fluellen, Linaria vulgaris is a member of the Plantaginaceae (the Plantain family) (note 4).

Linaria means “resembling Linum“, because the foliage of some species looks a bit similar to flax (Linum). Vulgaris means “common”. Other English names include Yellow Toadflax and Butter-and-eggs (both from the colour of the flowers).

Common Toadflax makes an ornamental and drought-tolerant garden plant, though its growth habit means you may need to keep an eye on its spread. I grew my plants from seed (from Emorsgate Seeds). Up until recently I grew them in large containers, but I have now planted some in a sunny bed in the front garden. In the past I tried to introduce container grown plants on the allotment but without success. I don’t know why they didn’t thrive – they should like sandy loam.

Linaria vulgaris has a long history of herbal use, listed on the Plants for a Future website. The plant was used as a laxative and diuretic. Extracts were used internally to treat oedema, jaundice, liver diseases, gall bladder complaints and skin problems and externally for haemorrhoids, skin eruptions, sores and malignant ulcers. However, it should only be prescribed by a qualified practitioner and should not be given to pregnant women. A yellow dye is obtained from the plant and a tea made from the plant has been used as an insecticide.

The Wild Flower Finder website lists several of the compounds found in Common Toadflax, including the lignan glycoside liriodendrin and two pyrroloquinazoline alkaloids, peganine and vasicinone.

The “toad” in the English name “Toadflax” may also relate to a medical usage. Apparently  the plants were used to treat bubonic plague and a false link may have been drawn between the words “bubo” (an inflammation of the lymph nodes) and “Bufo“ (a toad).

Common Toadflax flowers have nectar in their flower spurs and this attracts bumblebees. In Britain, only longer-tongued species such as Bombus hortorum (Garden Bumblebee) and Bombus pascuorum (Common Carder Bee) are able to get to this through the flower tube, but shorter-tongued species can overcome the problem by cutting a hole in the side of the spur and robbing the nectar without pollinating the flower.

I usually only see Common Carder Bees on the flowers but other species of bees will visit – the Emorsgate Seeds website features a Wool Carder Bee (Anthidium manicatum) hovering by a Common Toadflax plant (note 5).

Quite a few insects feed on Common Toadflax and the CABI website lists several, though it is mainly interested in them as biological control agents. One species I would like to find is the Toadflax Leaf Beetle, Chrysolina sanguinolenta. It is a rare and local insect but it occurs in Norfolk, especially in the Brecks, so if I keep on searching I may see it one day.

Notes

Note 1 – The BSBI Online Plant Atlas considers it to be a British native but the Wild Flower Finder website says that Common Toadflax may have been introduced to the UK as a garden plant. This is certainly true of its relative, Purple Toadflax, Linaria purpurea, which is native to Italy.

Clive Stace lists eight species of Linaria, plus three hybrids, in his “New Flora of the British Isles“ (Fourth Edition, 2019). Only Linaria vulgaris is native; Linaria repens (Pale Toadflax) is an archaeophyte (an alien which became established before AD 1500) and the others are neophytes (aliens which became established after AD 1500).  (Strictly, the cut off date is 1492, when Christopher Columbus voyaged to the New World.)

There are about 150 species of Linaria worldwide.

Note 2 – Information in this paragraph comes from https://www.cabi.org/isc/datasheet/30828#toDistributionMaps. CABI is the Centre for Agriculture and Bioscience International. Read more about the organisation and its work on its website: https://www.cabi.org.

Note 3 – The CABI fact sheet states that the roots are “widely but wrongly referred to as rhizomes (underground shoot structures)”. Plants “can establish from root fragments as short as 1cm long and the root system may penetrate up to one metre deep and several metres laterally, but shoots mainly originate from the shallower roots at depths of 2 – 5 cm”. Seed production and germination rates are usually low. Up to 100 seeds may form per capsule but viability may be no more than 25%.

Note 4 – Stace treats Linaria, Antirrhinum, Misopates, Veronica (Speedwells), Digitalis (Foxglove) and several other genera as the family Veronicaceae (Speedwell family).

Note 5 – We get Wool Carder Bees on Purple Toadflax (Linaria purpurea) in our garden.

Devil’s-bit Scabious, Succisa pratensis

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Devil's-bit Scabious, Succisa pratensis

Devil’s-bit Scabious, Succisa pratensis, at Buxton Heath, late August 2020.

We are now at summer’s end. Days are noticeably shorter and there are fewer flowers and insects, but there are still many things to look at and enjoy. Not least are late flowering plants such as Ivy (and its attendant insects), Grass of Parnassus and Devil’s-bit Scabious.

Devil’s-bit Scabious, Succisa pratensis, is flowering at the moment in Norfolk, and attracting plenty of hoverflies, butterflies and bees.

It is a perennial plant which has a basal rosette of leaves. From July onwards the plants send up nodding stems up to one metre (40 inches) tall, topped with flower heads, a tight bunch of buds (described as like boxing gloves) which open out into lilac-blue pincushions.

Succisa pratensis in bud

Succisa pratensis in bud: “like boxing gloves“.

Succisa pratensis

Succisa pratensis – open flower, like a pincushion.
Many more photos can be found on the Wildflower Finder website.

Devil’s-bit Scabious is one of three native species of scabious in the British Isles, the others being Small Scabious, Scabiosa columbaria, and Field Scabious, Knautia arvensis. Along with Teazels (Dipsacus sp.), these plants form a natural grouping: family Dipsacaceae (the Teasel family), or subfamily Dipsacoideae, part of the Caprifoliaceae (Honeysuckle family) (note 1).

Small Scabious grows in dry, calcareous grassland and in rocky places such as cliff tops, and Field Scabious grows in dry, grassy places on light soils. In contrast, Devil’s-bit Scabious is found in a wide variety of grassy places, including woodland rides, heathland and grassland and in mires, and in the uplands on cliff ledges and in ravines.

In Norfolk, Devil’s-bit Scabious grows in very different places: in valley mires and fens such as at Upton Fen and Buxton Heath, but also on the dry chalk ramparts of an Iron Age fort at Warham Camp. These areas have one thing in common:  more dominant species of plant are being held in check either because the soil is not particularly fertile, or because of grazing pressure.

Succisa pratensis is found throughout the British Isles in suitable areas where the grassland has not been “improved” (note 2), but it has had a widespread decline in southern and eastern England since 1950.

Scabious plants were used to treat skin conditions such as scabies (a contagious skin infestation caused by the mite Sarcoptes scabiei, note 3), and even bubonic plague. Devil’s-bit Scabious is still used in the treatment of eczema and other skin conditions. Other medicinal uses listed on the Plants for a Future website include the treatment of coughs, fevers and internal inflammations, and externally to treat bruises or conjunctivitis. Young shoots are edible and sometimes used in spring salads.

It is illegal to dig up plants without the landowner’s permission (note 4) and I don’t recommend it for Devil’s-bit Scabious, but if you did you would find that the root is black and rather short. The suggested reason was that the Devil bit the bottom of the root off, because he was angry at the plant’s medicinal qualities.

As well as being a great source of nectar for insects, Devil’s-bit Scabious is the foodplant of the Marsh Fritillary, Euphydryas aurinia. The butterfly is mainly found in the western half of Britain, having suffered a dramatic decline since the 1970s. I first saw one in The Burren in Ireland in 1985, with my next sightings over thirty years later, near Oban in Scotland (2018) and in the Lake District (2019), where the butterfly has been reintroduced.

Marsh Fritillary

Marsh Fritillary, Euphydryas aurinia.

We grow Small Scabious and Field Scabious in our garden. The former is in a gravel garden (now much wilder than when I wrote about it in 2013) and the latter in our wildflower meadow. Both do well in my dry, sandy loam. I haven’t tried growing Devil’s-bit Scabious but it would make a lovely addition to a garden, is very hardy and will flower for a long period.

The RHS website says that Succisa pratensis will grow in any moist soil in sun or partial shade and is excellent for peaty bog garden. Given that it grows wild in well drained conditions at Warham Camp, it might be worth experimenting if your soil is drier. Pot-grown plants are available online (for example, from Claire Austin and Sarah Raven), or you can buy seed (Emorsgate Seeds). Seed is best sown in the autumn: I might even give it a try.

Notes

Note 1 – Clive Stace considers the Dipsaceae to be a family, in his “New Flora of the British Isles“. (Fourth Edition, 2019.)

Note 2 – See Note 3 in my post about Green-winged Orchids.

‘pratensis‘ means ‘growing in meadows‘.

Note 3 – In Latin, scabere means to scratch.

The subspecies of mite Sarcoptes scabiei canis can infest dogs, cats, foxes, pigs, horses and sheep, causing sarcoptic mange.

The condition is very unpleasant in foxes and will lead to the death of an infected fox if it is not treated. It is probably the reason why fox numbers in our part of Norwich have crashed in recent years. (We no longer have foxes next door.)

The National Fox Welfare Society offers free mange treatment.

Note 4 – The Wildlife and Countryside Act (1981) makes it illegal “to uproot any wild plant without permission from the landowner or occupier” in Britain. See the Plantlife website for more information.

Yellow Loosestrife, Lysimachia vulgaris

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Yellow Loosestrife, Lysimachia vulgaris

Yellow Loosestrife, Lysimachia vulgaris, at Redgrave and Lopham Fen.

In mid July our friend Sarah drove us to Redgrave and Lopham Fen, rightly described as “the largest valley fen in England and one of the most important wetlands in Europe.” It is a Suffolk Wildlife Trust reserve, straddling the upper reaches of the River Waveney, which forms the border between Norfolk and Suffolk (note 1).

Yellow Loosestrife, Lysimachia vulgaris, was just coming into flower, forming patches of bright yellow amongst the reeds, in contrast to the pale lilac flowers of Creeping Thistles, Cirsium arvense, growing beside the path.

Yellow Loosestrife (or Yellow-loosestrife) is a characteristic perennial plant of river banks,  stream sides, marshes, fens and the edges of ponds and ditches. It is widespread in lowland Britain and Ireland where these conditions occur. It can be lost if wet places are drained or ditches are cleared but it can also colonise suitable new sites, possibly assisted by waterfowl (note 2). It grows to 1.5 metres (five feet) tall, with branching stems topped with clusters of attractive yellow flowers. Outside the British Isles, Lysimachia vulgaris is a native in many European countries, westwards into Asia and in Algeria in North Africa. It has been introduced into parts of North America and parts of New Zealand.

Along with the Cowslip (Primula veris) and Primrose (Primula vulgaris), which I’ve already written about, Yellow Loosestrife is a member of the Primulaceae, the Primrose family.  Stace’s Flora lists eleven species of Lysimachia in the British Isles (note 3). Lysimachia is named after Lysimachus, a king of Sicily, who is said to have fed a member of the genus to an angry bull to pacify it (note 4). Vulgaris means common. The English name “loosestrife” is shared with another waterside plant, Purple Loosestrife, Lythrum salicaria (family Lythraceae), but this isn’t a close relative (note 5).

Cowslips and Primroses flower in spring, but Yellow Loosestrife flowers much later, in July and August. (See The Wildflower Finder and First Nature websites for some excellent photographs of the plant in full flower.)

The genus Lysimachia is interesting because around 40% of the species, including Lysimachia vulgaris, have evolved to produce floral oils, rather than nectar, as a reward for visiting bees (note 6).

Floral oils are mostly made up of long-chain acetoxy-substituted free fatty acids and have the consistency of olive oil. They are secreted by special thin-walled glands on the stamen tubes and the inner, lower surface of the petals, known as trichome elaiophores. Floral oils are often scented: in a 2007 study by Dötterl and Schäffler, thirty-six compounds were detected in scent samples from Lysimachia punctata.

Floral oil production is found in some 1,500 to 1,800 species of flowering plants worldwide, in at least 11 plant families, and is thought to have arisen as many as 28 separate times.  Bees benefit from floral oils in two ways: they have a higher energy content than nectar or pollen and, as well as being used to feed the bee’s larvae, they are used to make a waterproof brood cell lining. (The adult bees don’t feed on the oils.) The oils are costly for plants to produce but this is worthwhile if the associated bee pollinates the flowers (note 7).

In England south of a line between The Wash and the Bristol Channel, Yellow Loosestrife’s flowers are attended by the solitary bee Macropis europaea, the Yellow-loosestrife Bee. The female bees have special projections on their basitarsi (the the basal segment of the tarsus) for collecting Yellow Loosestrife’s floral oils.

Yellow-loosestrife Bees were in attendance at Redgrave & Lopham Fen – both males swarming around the plants in search of females and females hard at work gathering pollen and floral oils. (The bees also visit plants such as Creeping Thistle and Water Mint for nectar.)

Yellow-loosestrife Bees nest in the soil, generally in banks or slopes. Nest sites are often at risk of flooding but the developing larvae and pupae are protected underground by a waterproof cell lining made from the floral oils. In Surrey, David Baldock found a Macropis europaea nest site at least 300 metres away from the nearest Yellow Loosestrife, and when he planted a single plant of Yellow Loosestrife in his garden pond, a male Macropis europaea visited within a week, even though he knew of no nesting sites or even Yellow Loosestrife within two miles of his garden (note 8).

A female Macropis europaea at work in a Yellow Loosestrife flower.

A female Yellow-loosestrife Bee (Macropis europaea) at work in a Yellow Loosestrife flower.

Yellow Loosestrife has a number of potential medicinal uses, listed on the Plants for a Futrue website, including “a serviceable mouthwash for treating sore gums and mouth ulcers”, to treat gastro-intestinal conditions such as diarrhoea and dysentery, to stop internal and external bleeding and to cleanse wounds. A yellow dye can be made from the flowers and a brown dye from the rhizomes. The plant has also been burnt in houses in order to repel or remove gnats and flies. The plant is described as astringent but a subspecies (Lysimachia vulgaris davurica) is grown in China for food.

As well as Redgrave & Lopham Fen, Yellow Loosestrife and its bee occur at other sites in Norfolk, including many of the Broads and at Strumpshaw Fen RSPB Reserve and on Beeston Common, near Sheringham.

If you want to grow Yellow Loosestrife, Emorsgate Seeds sell the seeds, which can be sown at any time of year. Grow it somewhere damp in a clay soil in sun or semi-shade and it should do well. If you live in the south you could even attract its attendant bee.

Notes

Note 1 – We were able to visit the northern half of the reserve (Lopham Fen) without needing our passports, as it lies in Norfolk. We had mainly gone to see invertebrates, including another attempt to see the Fen Raft Spider, Dolomedes plantarius

On previous trips to Redgrave & Lopham Fen in 2018 (including one by train from Norwich to Diss followed by a taxi ride), we failed in our quest, as the pools where the spider lives had mostly dried out. We finally found an immature specimen at Carlton Marshes, another Suffolk Wildlife Trust reserve near Lowestoft, in September 2019.

This year there was plenty of water and we managed to see two Fen Raft Spiders, one of which is pictured below.

Fen Raft Spider, Dolomedes plantarius

Fen Raft Spider, Dolomedes plantarius


Note 2 – The UK Wildflowers website gives an example of Yellow Loosestrife being outcompeted by Common Reed (Phragmites australis) at Hatchmere Lake in Cheshire. Regular cutting of reed, as at Redgrave & Lopham Fen, will presumably assist Yellow Loosestrife by keeping the reed bed more open.

Note 3 – Fourth Edition, 2019. Several are introductions, including the frequent garden throwout Dotted Loosestrife, Lysimachia punctata.

Other species of Lysimachia that I encounter in Norfolk are Bog Pimpernel (L. tenella, pink flowers, boggy, peaty ground), Scarlet Pimpernel (L. arvensis, scarlet flowers, a “weed” of arable land and gardens), Creeping Jenny (L. nummularia, damp places but surviving in shade in our back garden) and Yellow Pimpernel (L. nemorum, in woods. It “creeps” like Creeping Jenny but the leaves are more pointed).

I grow a form of Fringed Loosestrife, Lysimachia ciliata ‘Firecracker’, in the garden. It is far too dry for it on my sandy soil with minimal rainfall, even in semi-shade. I have to water it regularly in summer, but I like its contrasting purple leaves and bright yellow flowers.

When I first learnt plant names, Bog Pimpernel and Scarlet Pimpernel were both in the genus Anagallis.

Note 4 – Lysimachus means “scattering the battle” in Greek, and Wikipedia mentions several people of that name. To add to the confusion, one of them even founded a Greek city called Lysimachia (now in modern Turkey) and the First Nature website says that the plant was named after him, rather than the Sicilian king.

Note 5 – According to Merriam-Webster, “loosestrife” is intended as translation of Greek lysimacheios loosestrife (as if from lysis act of loosing + machesthai to fight).

Note 6 – Schäffler, F. Balao,and S. Dötterl studied a number of Lysimachia species and Table 1 in their paper lists which species produce floral oils. Lysimachia vulgaris produces them, as do L. punctata, L.ciliata, L. nummularia and L. nemorum. L. arvensis, and L. nemorum don’t.

See I. Schäffler, F. Balao,and S. Dötterl (2012), “Floral and vegetative cues in oil-secreting and non-oil-secreting Lysimachia species”. Ann Bot. 2012 Jul; 110(1): 125–138.

Note 7 – Much of my information on floral oils and bees comes from Bryan N. Danforth, Robert L. Minckley and John L. Neff’s superb book “The Solitary Bees – Biology, Evolution, Conservation” (Princeton University Press, 2019), particularly pages 177 – 186.

Worldwide, 440 species of bee have become morphologically and behaviourally specialised  upon oil-producing host plants.

Other plant families with species that produce floral oils include the Orchidaceae, Plantaginaceae, Scrophulariaceae, Cucurbitaceae and Iridaceae.

Note 8 – I highly recommend the late, great David Baldock’s book “Bees of Surrey” (Surrey Wildlife Trust, 2008).