MHG Volunteer Blog 26: Goat's rue

We're halfway through a year of brilliant weekly Medieval Herb Garden blogs! It was a hot one this week...

Find out more about the blog series here.

South-facing garden, clear blue skies and a temperature of 28°C before 9:30am – what a day! Today, we started (and finished) early due the heat.

We carefully worked around the fairy lights from Saturday's Proms at the Castle event, and helped to remove them. Dave, Caroline and Carole carried out some spot weeding - thistles, spent nigella, green alkanet, and of course the ever-present cinqfoil. Louis forgot to bring his long trousers - a must for the MHG! So instead, he helped to tidy up after ABBA at the Castle on Sunday and then watered all the potted plants.

Fairy lights for Proms at the Castle

After carrying out the Monday flower count, Carole talked with a group of students from New College Pontefract. They asked questions about volunteering in general and the MHG in particular. So, after 2 – 3 hours we all called it quits and went home for a lie down in a darkened room. 

Rain later in the week (hopefully).

Plant of the Week: Goat's rue (galega oficinalis) 

The English name 'goat's-rue' is a translation of the Latin 'Ruta capraria'. It was used for the plant in 1554 when it was considered to be related to 'Ruta graveolens', or common rue, and 'capraria', referring to goats. Its more modern Latin name, 'Galega', means 'to bring on milk'. It used to be fed to goats to increase milk production.

Goat's rue is originally from Europe and countries surrounding the Mediterranean. It is a robust, bushy, clump-forming, deciduous, leguminous, perennial plant. It grows to a height of 4.5ft and a width of 3ft.

It has smooth and branched stems. These bear pinnate leaves with from six to eight pairs of green, lance-shaped leaflets, ¾ to 2 inches long. The plentiful pea-like, white, lilac or purple flowers are borne on axillary erect racemes during mid-Summer to early Autumn.

Goat's rue will grow in sun or partial shade in moist, but well-drained, neutral to slightly alkaline soil. It has a slightly sweet scent when bruised, and a bitter, acidic taste.

Goat's rue growing in the Medieval Herb Garden

Folklore and other facts about goat's rue

In ancient Greece, goat's rue was believed to be a gift from the gods to help humans with their ailments.

In some cultures, goat's rue is believed to bring good luck. It is said to protect against evil spirits and witches if hung above doorways.

Goat's rue is sometimes used as a natural dye, producing a yellow or green colour. It has also been used as a replacement for rennet during cheese-making.

Medieval uses*

Medieval herbalists often included goat's rue in their potions and remedies. They believed it had magical properties.

Goat's rue was used for plague, worms, digestive issues, snake bites, all kinds of fevers, small-pox and measles and St Vitus' dance. It has a long history of use as a galactagogue, a substance that promotes lactation in nursing mothers.

The plant was believed to have diuretic properties, helping to flush out toxins from the body. Some traditional practices suggest its scent may have calming or relaxing effects.

Raw goat’s rue is considered poisonous to livestock. While human poisoning is rare, the plant can cause headaches, weakness and potentially interfere with blood clotting medications.

Modern uses*

Culpepper’s 'Complete Herbal' (1653) said to use goat’s rue for symptoms we now know are symptomatic of type-2 diabetes. 200 years later, scientists discovered that goat’s rue is rich in a chemical called guanidine, which lowers blood sugar levels. Unfortunately, this can be toxic.

However, a chemist, George Tanret, identified a slightly less toxic compound from the plant called galegine. A synthesised form of this chemical is the basis for metformin. This is the most commonly prescribed drug for type-2 diabetes today.

*Please don't use any plants mentioned in these blogs as medicine without advice from a doctor.

In time for Pontefract Liquorice Festival, next week’s Plant of the Week will be liquorice!