
<em>Polemonium</em>: to plant, to grow, to care for
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Polemonium, in a nutshell
- Polemonium, known as “Jacob’s ladder”, is a short-lived perennial that self-seeds readily.
- In spring it produces lush foliage resembling a dark green or variegated frond.
- Long stems topped with cup-shaped flowers reminiscent of Geranium or Myosotis flowers appear from spring to autumn.
- These plants are very easy to grow in cool, well-drained soils, in sun or partial shade, even in shade if mainly foliage is desired.
A word from our expert
Polémonium, sometimes called Polémoines, are somewhat forgotten plants formerly very common in our grandmothers’ gardens for their splendid arched foliage reminiscent of fern. The luxuriance of their deeply divided leaves in glossy dark green shades, sometimes nicely variegated with cream or pale pink, their ease of cultivation, their excellent hardiness and their spontaneous sowings have certainly contributed to their success. They also enjoy a long flowering in bluish, violet, white or pale pink hues that brings a lovely brightness to woodland edges or shaded banks.
The flowering of Polémoniums stretches over around two months, beginning with that of late tulips, peonies and oriental poppies, with which Polemonium coeruleum harmonises beautifully. The airy quality of the flowering also accompanies that of old garden roses with grace. The cultivar ‘Brise d’Anjou’, selected by Pépinières Prouteau for its distinctive cream‑striped foliage, also produces a later display from August to October of deep violet‑blue, while Polemonium reptans flowers in May–June, dotting the matte green foliage with dense heads of lavender‑blue or white.
Polemoniums make very pretty bedding plants, often used in borders, but that also suit a rockery even if slightly calcareous. They appreciate rich, clayey and cool soils as well as drained humus‑bearing soils. Groundcover species such as Polemonium pulcherrimum and carneum can cover a trough or a sunny to semi‑shaded rockery. Some species self‑seed easily if spent flowers are left.
Description and botany
Botanical data
- Latin name Polemonium
- Family Polemoniaceae
- Common name Jacob's ladder, Greek valerian, Polemonium
- Flowering between May and October
- Height between 0.25 and 0.70 m
- Sun exposure sun or partial shade
- Soil type any fresh well-drained soil, light humus-bearing or rocky
- Hardiness Excellent (-30 to -20 °C)
The Polemonium are perennials or annuals that belong to the family Polemoniaceae and include 38 species. They are distributed across temperate regions of the Northern Hemisphere and the Arctic.
Polemonium caeruleum, also called Greek valerian, is the only species found wild in France where it is protected. This montane species occupies woods and damp pastures of high mountains up to 2000 m altitude in the Jura, Savoie, Haute-Loire, Puy-de-Dôme, Cantal and central Pyrenees but extends into central and northern Europe, the Caucasus, Siberia and North America. Its origins explain very good adaptation to cold, humid climates. It dislikes humid heat. This species forms a rosette of dense leaves topped by several rather stiff violet-blue flowering stems measuring 30 to 80 cm, even up to 120 cm in height. It has given rise to different cultivars with white flowers, large flowers reaching 2 cm across such as ‘Lambrook Mauve’, leaves marginate with cream such as ‘Brise d’Anjou’…
The fern-like leafage characteristic of Polemoniums has dozens of small pointed leaflets, inserted perpendicularly to the central vein, like the rungs of a ladder hence the nickname Jacob’s ladder, and are odd-pinnate.

Polemonium caeruleum – botanical illustration
The alternate leaves petiolate form a luxuriant mound at the base while they adorn the flowering stems in a more scattered and discreet way.
The flowering stems are hollow and marked with furrows, bearing at their tip a panicle of airy flowers of a pretty violet-blue from spring to late summer that contrasts with the intense green colour of the foliage. The corolla, surrounded by a green calyx with 5 hairy and glandulous lobes, has a short tube ending in 5 obtuse oval lobes forming a cup 0.8 to 1.5 cm wide. The flower centre, tinged with golden yellow, is crowned by 5 pale-yellow stamens becoming golden at ripeness and a long white pistil ending in 3 points. The genus offers a surprising diversity of flowers such as the orange tubular corollas of P. pauciflorum, the large pale-blue bells of Polemonium Stairway to Heaven or an intense blue in P. caeruleum Sapphire, the funnel-shaped pale-pink flowers of Polemonium carneum Apricot Delight…
The slightly scented flowering attracts bees and butterflies, eager for their pollen.
The fruits are three-angled capsules containing 4 to 6 seeds within each of the three chambers.
Cut flowers of Greek valerian keep well in a vase; the variety Sonia’s Bluebell is particularly dedicated to this use as its flowering renews from May to August.
In the past, dried roots of Polemonium reptans were used in herbal medicine in the eastern United States. They were harvested in autumn, then dried for later use.

Some Polemoniums: P. caeruleum ‘Bressingham Purple’, P. reptans ‘Blue Pearl’, Polemonium ‘Lambrook Mauve’, P. carneum ‘Apricot Delight’ and the pretty variegated foliage of P. reptans ‘Touch of Class’
Main varieties of Polemonium

Polemonium caeruleum Lambrook Mauve
- Flowering time July to September
- Height at maturity 40 cm

Polemonium reptans Touch of Class
- Flowering time June, July
- Height at maturity 40 cm

Polemonium carneum Apricot Delight
- Flowering time June to September
- Height at maturity 40 cm

Polemonium Sonia's Bluebell
- Flowering time June to August
- Height at maturity 50 cm

Polemonium yezoense Purple Rain
- Flowering time July to October
- Height at maturity 50 cm

Polemonium caeruleum Brise d'Anjon
- Flowering time June to September
- Height at maturity 50 cm
Discover other Polemonium - Jacob's Ladder
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Planting
Where to plant Polemonium?
Polemoniums are easy to grow and can be planted in any soil that remains cool in summer but drains well. They prefer soils rich in humus. Avoid overly acidic or very calcareous soils.
Choose a situation that is not too hot in full sun or a position in partial shade. Planting in shade produces few flowers but remains attractive for the aesthetic of the glossy dark green divided foliage, variegated with cream or purple.
Avoid combination of high heat and humidity in regions with hot summers. Foliage is sensitive to burning sun, so this plant is best in regions with cool summers.
Polemoniums are very hardy and can withstand temperatures of -20 to -30°C depending on species.
When to plant?
Polemoniums are best planted in autumn to encourage good establishment before summer.
How to plant?
This plant is easy to grow.
- Soak the buckets in a bucket of water.
- Work plot with a digging fork to loosen soil deeply.
- Place young plants about 50 cm apart.
- Dig a hole the size of the rootball with a small trowel.
- If soil very clayey, add a shovelful of compost to each hole or plant on a raised mound to ensure good drainage.
- Remove the bucket and tease out any circling roots if necessary.
- Plant the rootball taking care not to bury the collar and firm lightly.
- Water then mulch.
Polemoniums can be grown in large pots of at least 18 cm diameter. Fill container, pierced at base, with a mix of potting compost and coarse sand.
Caring for Polemonium
Care is simple and comes down to a few steps :
- Keep soil cool, even in summer.
- To restart flowering and improve foliage retention, cut back some faded inflorescences. Leave a few seedheads to ensure renewal of young plants, which have a fairly short lifespan.
- If the plant tends to spread too much, remove the seedheads.
- Polemonium does not need dividing and does not tolerate transplanting well.
- Fertilising is unnecessary.
Multiplication
Easiest method of propagation is to divide clump in spring or autumn but Polemoniums can also be obtained by propagation by cuttings of young spring shoots or by sowing in autumn or indoors in February–March.
Polemoniums are generous: they tend to self‑seed abundantly yet never become invasive. They are then very easy to transplant.
Division de touffe
Proceed when foliage is barely developed in late winter or in autumn before dying back :
- Using a spade, separate rosettes including as many roots as possible.
- Replant immediately in light soil, without burying collar.
Propagation by cuttings
Prepare a deep pot by filling with potting compost mixed with sand or prepare a patch of soil sheltered by a cold frame ;
- Take shoot tips about 10 cm long.
- Remove leaves near base of cutting.
- Insert them to two‑thirds of their length, leaving sufficient space between them for development until following spring.
- Press down gently around each to remove air pockets and ensure good contact between compost and cutting.
- Place them under cold frame in shade.
- In following spring, separate rooted cuttings and plant out in final position.
Sowing
- Harvest Polemonium seeds in June or July by opening capsules.
- If sowing in spring, refrigerate seeds for a few weeks before sowing.
- Sow in a seed tray filled with seed compost, lightly covering seeds.
- Water gently and place in heated room. Germination occurs in 10 to 14 days.
- Prick out seedlings into buckets when they can be handled.
- Pinch stems when strong enough to encourage them to ramify.
- Plant them in autumn if clump has grown robust, or wait until following year.
Uses and companion plants
Greek valerian is a border plant well suited to mixed borders to bring lightness alongside other perennials or to flower the base of roses. Stage it in a bed of blue–pink–white tones or in contrast with a complementary shade such as orange. Its flowering coincides with that of late tulips, Oriental poppies, peonies, Potentilla fruticosa ‘Hopleys Orange’ and globeflowers, as well as columbines, daylilies and geums, which also like fresh soils.

An idea for a part-shade combination: Polemonium caeruleum ‘Bressingham Purple’, Geranium phaeum ‘Samobor’, Brunnera macrophylla ‘Mr Morse’, Polystichum setiferum ‘Proliferum’, Aquilegia ‘Green Apples’ (‘White Barlow’ would also suit), Allium aflatunense ‘Purple Sensation’
Play with foliage combinations by mixing broad leaves of Hostas and Brunnera, the fronds of ferns, and the dentate, richly coloured leaves of Heuchera, within a woodland garden or a part-shade rockery.
Define shaded path edges with a border of Greek valerian which, with its delphinium-like habit, provides attractive groundcover and generous flowering.
You can also place a specimen on display, such as Polemonium yezoense ‘Purple Rain’, whose purple foliage remains decorative for a long time, in a deep pot to serve as a focal point.

One example of a combination: Polemonium and knotweed (here, Polygonum alpinum) make good companions (astilbes such as ‘Sprite’ or ‘Hennie Graafland’ would also work well) !
In a rockery or on a border, the spreading forms of Polemonium reptans can mingle with the bells of pasque flowers strongly tinged violet or carmine red or white spring anemones (Anemone sylvestris…). The variety ‘Touch of Class’, with very soft grey‑green foliage, finely marginate with white, prefers part-shade to shaded exposures such as a shady understorey, courtyard or shaded garden. It pairs beautifully with blue Corydalis, bleeding hearts, Geranium nodosum or Epimediums. It is also a good plant for decorating edges of water points and very useful in naturalistic gardens for attracting pollinating insects.
Useful resources
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