Polemonium caeruleum

Polemonium caeruleum
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Asterids
Order:	Ericales
Family:	Polemoniaceae
Genus:	Polemonium
Species:	P. caeruleum
Binomial name
Polemonium caeruleum L.

Polemonium caeruleum, known as Jacob's-ladder^[1] or Greek valerian, is a hardy perennial flowering plant. The plant produces cup-shaped, lavender-coloured or white flowers. It is native to temperate regions of Europe.

Growth

The plant usually reaches a height from 45 to 60 centimeters (18 to 24 inches), but some occasionally will be taller than 90 centimeters (35 inches.) The spread of the plant is also 45 to 60 centimeters. It can grow in North American hardiness zone 2.

Habitat

The plant is native to damp grasslands, woodlands, meadows and rocky areas in temperate areas of Europe.

Cultivation

The plant normally prefers soil that is rich in moisture and lime and does not require as much sunlight as other plants. Depending on the conditions, it will need varying amounts of water in the summer. If it is hot summer, the plant may require extra water. If it is an average summer, it probably won't need extra water. Normally hardy, some varieties (e.g. Blue Pearl) behave as tender biennials, which means they are effectively annuals in cooler climates (below hardiness zone 6).

Cultivated varieties include Blue Pearl and Brise d'Anjou. White flowered (Album, White Pearl) and a variegated (Snow and Sapphires) ^[2] variety are available.

(Cats are attracted to the scent of the plant, particularly younger plants. A person who is growing Greek valerian in a container or home garden should protect the plants if they own a cat.)

Uses

Historical medical uses

The plant was first used as a medicinal herb in ancient Greece. The ancient Greeks used the root to treat dysentery, toothaches and animal bites. The plant was also found in a few European pharmacies during the nineteenth century and was used as an antisyphilitic agent and to treat rabies. Today, the plant is not usually used medically.

Other uses

Polemonium caeruleum was voted the County flower of Derbyshire in 2002 following a poll by the wild plant conservation charity Plantlife.^[3]

Today, the plant is usually used in potpourris and is boiled in olive oil to make black dyes and hair dressing, but it has few other significant uses.

Bees work the flowers for both pollen and nectar. Flowers of other species of Polemonium are also useful honey bee forage.

References

1. "BSBI List 2007". Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-02-25. Retrieved 2014-10-17.
2. Paghat's Garden: Snow and Sapphires
3. "County Flowers". Plantlife. Retrieved 19 August 2013.

• Biggs, Matthew, Vegetables, Herbs & Fruit: An Illustrated Encyclopedia, (2006) p324-325. Firefly Books Ltd., ISBN 1-55407-126-7
• Bremness, Lesley, Herbs (Smithsonian Handbooks), (1994-2002) p205. Dorling Kindersley, Inc., ISBN 0-7894-9391-8
• Howes, F.N., Plants and Beekeeping, (1979) p161 Faber Paperbacks, ISBN 0-571-11358-3

Sources

• BBC Plant finder

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  Boreal Jacobs-ladder

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  Boreal Jacobs-ladder

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  Leaves