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A wide variety of plants growing in the Medieval Herb Garden on a sunny day

Medieval herb garden blog 75: Hound's tongue

Wednesday, June 17, 2026

Week 75 volunteer update

Today, the Medieval Herb Garden got a visit from two people who are planning a series of workshops using natural dyes. The events will be Pontefract Castle. They talked to Carole to see if it would be possible to use some of the plants from the garden. Over 150 of the plants we grow can be used for dyeing purposes!

Dave carried out some weeding. Carole did the plant count and added some more plants to the sales barrow. Meadowsweet is now available.

The clary sage is looking particularly nice at the moment.

Lots of small pale purple flowers growing up tall green stems

Clary sage in bloom in the Medieval Herb Garden

Plant of the week: Hound's tongue (cynoglossum officinale)

'Cynoglossum' combines the Greek 'cynos' ('of a dog') and 'glossa' ('tongue'). This leads to its common name of hound’s tongue.

Its other common names are houndstooth, dog's tongue, gypsy flower, sheep lice, beggar’s lice and rats and mice.

Hound's tongue is native to Europe and Asia. It can be either an annual or a biennial bushy, herbaceous, evergreen plant. In its second year it can grow up to 3 ft (90 cm) in height with a spread of 2 ft (60 cm). It can grow in any moist, but well-drained, soil type. Hound's tongue grows in full sun to partial shade, in any position but north-facing.

During its first year of growth, hound's tongue is a low-lying, grey-green basal rosette of a dense cluster of large, hairy leaves. The leaves are typically up to 1 ft (30 cm) long and 2 inches (5 cm) wide. The leaves are oblong-lanceolate and taper at the base. They have a similar shape and roughness as a dog's tongue.

In the second year, from May to September, it produces flower spikes. They grow in loose clusters of dark purple-red, funnel-shaped flowers. The flowers grow on hairy stems up to 3 ft (90 cm) high.

Hound's tongue has a dark brown to black woody taproot. This branches out, allowing the plant to compete with other plants for nutrition. The seeds are teardrop-shaped 'nutlets' covered in barbed, 'Velcro-like' hooks.

Tall green stems with tiny clusters of dark purple flowers

Hound's tongue beginning to flower in the Medieval Herb Garden

Culinary uses of hound's tongue

Historically, some wild foraging books have said that young leaves could be cooked as a bitter potherb, or the seeds roasted as a coffee substitute.

However, hound's tongue should never be eaten. It contains pyrrolizidine alkaloids. These can cause severe liver damage and cancer if eaten or otherwise taken internally.

Use of hound's tongue as a dye plant

The leaves, stems and roots of hound's tongue have been used to produce dyes. The colours range from rich dark greens to soft browns.

Folklore and other facts about hound's tongue

European folklore states that if you place a leaf of hound's tongue in your shoe, dogs won’t bark at you.

The plant remains toxic whether fresh or dried. It is a severe threat in hay pastures.

The Royal Cornwall Gazette of 7 September 1805 said that hound’s-tongue ‘gathered full of sap and bruised with a hammer’ would make mice and rats run away.

Hound’s tongue may be pollinated by bees. It may also self-pollinate.

Medieval medicinal uses of hound's tongue*

Historically, hound’s tongue was used to treat coughs, baldness, scalds, burns, the bites of mad dogs, dysentery, haemorrhoids, “St Anthony’s Fire” and “the King’s Evil”.

It was also known that “The distilled water of the herbs and roots is a remedy for all the purposes aforesaid, to be used inwardly to drink, and outwardly to wash any sore place, for it heals all manner of wounds, and all the foul ulcers that arise by the venereal disease.”

*As always, this isn't to be considered medical advice today. Please don't use any plants mentioned in these blogs as medicine without advice from a doctor.

Medieval herb garden blogs

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