Introduced in 2006, Polemonium yezoense 'Purple Rain' is one of the best new introductions in recent years. With bronze-purple lacy foliage, dark stems and violet-blue flowers, it is the darkest flower form of Polemonium available.
The original seed was collected at altitude in Japan where it is already accepted as one of the largest flowered gems of the race. In 1991, in one tray of seedlings, one plant developed with darker foliage which was especially notable in spring when it developed a purple rosette. Subsequent generations retained this feature, with a proportion being extremely darker leaved. This new colour break in polemoniums made it an extremely valuable introduction which has since been produced, and even re-named, by many well-known companies worldwide.
Polemonium yezoense 'Purple Rain' is the original form. A striking clump-forming perennial with mounds of finely cut deep foliage that deepens to a rich dark purple hue in spring and autumn.. This genus is distinguished by its fernlike foliage, dozens of tiny leaflets are held out perpendicularly to the central stem, like rungs on a ladder.
In late spring or early summer, dark-burgundy stems rise upward and display loose clusters of five-petalled, bell-shaped flowers that are violet-blue. In the cream-coloured centre of each flower are orange stamens each covered with pollen. It may re-bloom by early autumn if spent blooms are removed regularly.
Polemonium yezoense 'Purple Rain' is a fabulous hardy and vigorous garden plant is at its best growing in a position with full sun or part-shade, in cool, moist, humusy soil. It combines beautifully with other leaf and flower colours and is a good choice for mixed borders, woodland gardens, rock gardens and as specimens where their exciting blooms draw the eye over mounds of lovely, dark coloured foliage.
Sowing: Sow in Autumn or Spring
Sow at 15 to 18°C (59 to 65°F) on to the surface of a moist seed sowing compost and cover lightly with vermiculite.
Germination should begin to take place after 14 days. Maintain a temperature of 15°C (59°F) after germination for the Autumn sowing and keep temperatures cool for the Spring sowings to help avoid any loss of germination, which can be caused by high temperatures.
Grow on the seedlings in light shade. When they are established, prick out each seedling as it becomes large enough to handle and transplant into 7.5cm (3in) pots or trays. Over winter in a well ventilated unheated glasshouse, tunnel or cold frame.
After the last expected frosts, gradually acclimatise to outdoor conditions for 10 to 15 days before planting out into their permanent positions, space 22 to 30cm (9 to 12in) apart.
Polemonium prefer rich, humusy, consistently moist soils, in full sun or partial shade.
Plants are intolerant of the high heat and humidity of areas with hot summers. The foliage may scorch in too much sun and leaflet tips will brown up if soils are allowed to dry out. The best performance occurs in cool summer climates.
Cut back the plants to basal foliage after blooming to tidy the planting and to encourage a possible late summer rebloom. They will self-seed in optimum growing conditions. Cut back to the base in autumn.
Jacob’s ladders generally don’t need to be divided and can be slow to recover if you try it, so consider taking stem cuttings in summer if you want to propagate your favorites. The plants can be long lived where the growing conditions are just right, elsewhere, they may fade away after a few years, so consider letting a few flower stalks set seed to get self-sown seedlings for replacements.
Shade and Woodland Gardens. Under planting of trees. Rock Gardens, Cottage/Informal Garden, Flower Borders or Wildlife gardens
Polemonium is a genus of about 30 species of flowering plants in the family Polemoniaceae, native to cool temperate to arctic regions of the Northern Hemisphere and also in the southern Andes in South America. Many of the species grow at high altitudes in mountains.
Polemonium yezoense is native to the mountains of Hokkaido, the northernmost of the large islands of Japan.
Pronounced poe-lih-MOE-nee-um yez-oh-EN-see, the genus name derives from the Greek polemonion, a name used for a medicinal plant associated with the philosopher Polemos of Coppadocia. The Greek polemos means 'war'. Pliny the Elder claimed that the name was taken from a war between two kings who both claimed to be the first to discover the plant's medicinal properties.
The species name yezoense, means 'of or from Hokkaido, Japan'. Yezo is the Japanese former name for Hokkaido, the northernmost of the large islands of Japan.
The leaves give the plant its common name of Jacobs Ladder as they are divided like ladder rungs. In Roman times it was believed to symbolise the ladder that spanned heaven and earth in Jacob’s dream.
Polemoniums are often commonly called Greek Valerian, from its historical use by ancient Greek physicians. Despite this, it is not related to the true valerian (Valeriana officinalis).
- Additional Information
Packet Size 30mg Average Seed Count 25 Seeds Family Polemoniaceae Genus Polemonium Species yezoense Cultivar Purple Rain Synonym Polemonium yezoense var. hidakanum 'Purple Rain' Common Name Japanese Jacob's Ladder Other Common Names Jacobs ladder Hardiness Hardy Perennial Flowers Blue cup-shaped flowers Natural Flower Time June to August Height Height with Flowers: 50cm (20in) Spread 45cm (18in) Position Full sun to partial shade Soil Moist, Moderately fertile but well drained Time to Sow Sow in autumn or in spring.