Plant of the Week – Laburnum anagyroides

First written and posted on 19th November, 2013. Please click here if you would like to read the original post on This and That.

This week’s plant is Laburnum anagyroides, the common laburnum tree. I chose it because there is a beautiful archway of laburnum at Ashridge, which is currently being given a winter prune. I love the long, flowing recemes (chains) of fragrant flowers, I can’t wait to see the arch in full bloom next summer! I hope you find the information interesting. 🙂

Laburnum arch at Bodnant Garden

Genus: Laburnum

Species: anagyroides

Family: Fabaceae

Common name: Common laburnum

Type of plant: Tree

Origin: Native to central Europe

Technical details

The ideal growing conditions for Laburnum anagyroides are in full sun, in an exposed or sheltered position with well-drained soil.

Soil: Laburnum anagyroides thrives in most soil types and pHs, including: acid, alkaline and neutral: and chalk, clay, sand and loam.

Resilience: Very hardy.

Propagation: Propagation is easiest by grafting.

Cultivation: Laburnum anagyroides is a small deciduous tree, growing no more than seven metres in height. It is a popular ornamental tree in parks and gardens, known for its bright yellow pea-like flowers that are densely packed in pendulous racemes, blooming in late spring and summer.

Laburnum racemes

Pest and disease problemsLaburnum anagyroides is prone to aphids and leaf-mining moths and flies. Powdery mildew and silver leaf can sometimes be a problem too.

Interesting Facts

1. The seeds of Laburnum anagyroides are legumes with large numbers of black seeds that contain cytisine, an alkaloid extremely poisonous to humans but also goats and horses, especially when not ripe.

2. The cytisine is present primarily in the flowers, seeds and roots. Initial symptoms of poisoning appear thirty minutes to an hour after ingestion, and include: burning mouth, nausea and vomiting. Subsequent symptoms are intense stomach and intestinal cramps, sweating, headaches and muscle spasms. Fatal poisonings are manifested as whole-body paralysis with death from lung paralysis in one to several hours.

3. During World War I experiments were conducted aimed at using Laburnum anagyroides to replace tobacco because the principal psychoactive chemical cytisine has similar effects to nicotine.

4. In earlier times the seeds and leaves of Laburnum anagyroides were used as a psycho-pharmaceutical agent to treat excessive irritability, psychoneurotic illnesses, migraines, chronic arsenic poisoning and liver ailments.

5. Most poisonings of Laburnum anagyroides occur in children, because they are attracted to the seed pods.

6. The hard, dark greenish timber of Laburnum anagyroides is valued in cabinet-making.

7. The English poet Francis Thompson described Laburnum anagyroides in one of his poems “Sister Songs” (1895):

“Mark yonder, how the long laburnum drips

its jocund spilth of fire, its honey of wild flame!”

8Bodnant Garden in Wales is famous for its magnificent Laburnum arch which is fifty five metres long.

9. There are two species of laburnum, Laburnum anagyroides and Laburnum alpinum. Most garden specimens are a hybrid between these species, which is Laburnum x watereri ‘Vossii’ commonly known as Voss’s Laburnum.

10. Laburnum x watereri ‘Vossii’ gained the Royal Horticultural Society’s Award of Garden Merit, meaning it is a plant of outstanding excellence.

Laburnum drawing

Resources

RHS A-Z Encyclopedia of Garden Plants

The Hillier Manual of Trees and Shrubs

Collins Tree Guide

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