Lupin: sowing, planting and care

Description and botany

The Lupin or Lupinus is a perennial, bushy or annual plant depending on species, belonging to large family Fabaceae, formerly known as Papilionaceous or Legumes, like wisteria, broom or sweet pea. The genus Lupinus comprises nearly 200 species native to dry meadows, hills, open woods, coastal strips, cliffs or riverbanks around Mediterranean basin, North Africa and across the Americas.

While Lupinus polyphyllus, the garden perennial lupin, is the most common species, there are many perennial hybrids, notably the lupinus x russellii or Russell hybrids obtained by cross-breeding Lupinus polyphyllus with Lupinus hartwegii (hairy lupin), an annual species.

Varieties belonging to the group of Russell hybrids are widespread in gardens, such as ‘Le Chandelier’, ‘La Châtelaine‘ or ‘La Demoiselle’, which are among best-known cultivars. Occasionally encountered is Lupinus arboreus, the arborescent lupin, a bush that can reach 2 m in height, and Lupinus nanus ‘Pixie Delight’, a dwarf lupin only 50 cm tall.

Some annual species such as Lupinus alba, white lupin, Lupinus luteus, yellow lupin, and Lupinus cruckshanksii (or mutabilis) with changing colours, grouped under name of ‘sweet lupins’, are grown for food or forage because of their seeds very rich in protein. They can also be cultivated as ornamentals.

Lupinus luteus – botanical illustration

From a strong taproot that anchors deep in soil, lupin forms an erect, bushy and vigorous clump with a more or less compact habit and height ranging from 45 cm in flower, with similar spread, up to around 1.50 m. Size varies with variety but most lupins remain medium-sized and rarely exceed 90 cm in height.

Although growth is rapid, perennial species are short-lived, living about 3 to 5 years, but they self-seed easily.

Lupin quickly forms a dense shrub with strikingly architectural foliage. Deciduous leaves, mainly basal, are palmate, divided into rosettes of five to 12 lanceolate to spatulate leaflets radiating from a single petiole. Measuring 1 to 6 cm long, leaves are bright green to silvery green and often covered with silky hairs beneath.

Lupins’ showy flowering never goes unnoticed.

From this clump of deeply divided leaves emerge, from late spring to mid-summer, sometimes with a repeat in September, the long, upright spikes so characteristic, borne on a thick flowering stem.

Small flowers 1 to 2 cm long are grouped along this spike in compact clusters sometimes reaching up to 60 cm in length. With fused petals and an asymmetrical shape, lupin flowers resemble those of peas.

Flower buds open successively from base to tip of spike, extending display of these impressive but, like delphiniums, unfortunately rather short-lived blooms.

In first year of flowering, plant tends to produce spikes of disciplined regularity, while in following years it will display many leading shoots of varying sizes.

These plump cones densely covered with pea flowers bear bright and varied colours of carmine pink, red, lilac, blue, orange, purple or white. Some flowers are bicoloured, notably in variable lupins, combining white with another colour.

These tall, vividly coloured inflorescences, sometimes very fragrant, emit a delicate peppery scent similar to that of wisteria and sweet pea.

Palmate foliage, highly decorative / flowers, always spectacular / pods containing developing seeds

Highly melliferous, they attract many pollinating insects throughout season.

Lupin flowers are lovely in fresh country-style bouquets with romantic feel.

Once faded, lupin flowers turn into pods containing seeds that can reach up to 14 cm in diameter and which readily self-sow. Garden lupin seeds contain bitter toxic alkaloids while seeds of so-called annual “sweet” lupins are grown for their very low alkaloid content. Since antiquity, large yellow lupin seeds have been eaten as a snack, pickled like olives.

Easy to grow, hardy down to about -15°C for perennial species, lupin prefers a sunny or partially shaded site with soil rich in humus, deep, staying cool during growing season and above all non-calcareous, as it dislikes lime as well as excess winter wet.

Whether perennial or annual, lupin is a reliable choice for perennial borders, a showpiece in English gardens. It fits perfectly into naturalistic borders to compose displays that are exuberant yet ephemeral.

With its columnar habit, it is valuable for adding verticality at back of border, in flowerbeds or even in a pot near house.

Lupin is also grown as green manure because its roots release nitrogen, improving poor soils over years. Today, seeds of food lupins, rich in protein, are processed into flour — a reminder that lupin is a legume!

Main species and varieties

Most popular perennial lupins

Our favourite perennial lupins

Another interesting variety

Our favourite annual lupin seeds

Lupinus polyphyllus The Chatelaine

It displays bicoloured flowers in pink and white. Plant in groups or singly in borders of perennial beds and flower beds. Indispensable in a romantic garden!

• Flowering time July, August
• Height at maturity 90 cm

See the product sheet

Lupinus polyphyllus Noblemaiden

A perennial of good hardiness that spreads without being aggressive. Plant in borders of perennial beds and flower beds.

• Flowering time July to September
• Height at maturity 90 cm

See the product sheet

Lupinus polyphyllus Chandelier

This very floriferous cultivar is a safe bet! It forms superb clumps with deeply divided leaves, topped with large yellow spikes in low-maintenance beds.

• Flowering time July, August
• Height at maturity 90 cm

See the product sheet

Lupinus The Governor

A bushy, hardy cultivar, indispensable in beds and borders of blue gardens.

• Flowering time July, August
• Height at maturity 90 cm

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Lupinus West Country Manhattan Lights

Exclusive! A hybrid lupin that brings cheer to rockeries and borders.

• Flowering time July, August
• Height at maturity 80 cm

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Lupinus polyphyllus My Castle

An exceptional cultivar with a striking colour range in gradients of carmine pink, red and purple. Its tall inflorescences majestically tower over flower beds.

• Flowering time July, August
• Height at maturity 90 cm

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Lupinus Gallery Yellow

It is part of a series of very squat, hardy and remarkably floriferous hybrids, also resistant to diseases. An undeniably cheerful colour.

• Flowering time June to August
• Height at maturity 60 cm

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Lupinus Gallery Pink

This lupin has pretty silvery foliage that brightens shaded areas. Its large pink spikes will make a splash in borders of perennial beds and flower beds.

• Flowering time July, August
• Height at maturity 60 cm

See the product sheet

Lupinus arboreus

Here is a shrubby lupin that can reach 2 m in height. This tree lupin forms an imposing bush with pale yellow flowers.

• Flowering time June, July
• Height at maturity 2 m

See the product sheet

Lupinus Avalune Red-White - Annual Lupin Seeds

A novelty for borders and flowering containers! Fast-growing and compact, it flowers in short bicoloured spikes of red and white.

• Flowering time July, August
• Height at maturity 40 cm

See the product sheet

Lupinus Avalune Lilac - Annual Lupin Seeds

This lupin blooms for a very long time. It is a dwarf annual variety with very original bicoloured flowering, perfect in window boxes.

• Flowering time June to November
• Height at maturity 40 cm

See the product sheet

Planting

Where to plant Lupins?

Perfectly hardy down to -15 to -20°C, the Lupin perennial tolerates cold winters and thrives in many parts of France. Lupin is rather a plant of cool climate.

Annual or perennial, it is an easy-to-grow plant that prefers sunny positions essential for good flowering. It will tolerate light shade in southern regions.

Although lupins do well in any good, well-drained garden soil, even poor soil, they prefer rich soils, neutral to slightly acidic, that stay cool during the growing season and, above all, are free of lime. They will even tolerate clay soils if sufficiently fertile. They will adapt to poor soil but will be less luxuriant.

Cultural needs of some lupins differ. This is the case for Lupinus arboreus, which prefers a light, free-draining, even dry soil.

All lupins cannot tolerate wet, poorly drained soils in winter.

Lupin has a wide ground spread and its taproot does not like transplanting. Offer it a space suited to its ample development: growth is rapid and it will often reach up to 75 cm wide at ripeness. It must not be crowded; surround it with plants that have little ground spread.

The arborescent lupin forms a clump nearly 2 m across. A well-exposed site sheltered from strong winds, which could shorten the flowering, will encourage the plant to reach full height.

By nature somewhat free-seeding, lupin will self-seed when conditions suit it.

Lupins remain interesting focal points in a garden. Planted in groups, they structure space and bring verticality, texture and presence to natural gardens, to the middle or back of large perennial herbaceous beds, along a wall or on a raised bank.

They help give structure to rather flat beds and add relief to a mixed-border.

Low varieties fit more easily on the edge and in a pot on a sunny terrace.

When to plant perennial lupin?

Perennial lupin buckets are best planted in spring after last frosts, from March to May, or in autumn from September to November.

How to plant perennial lupin?

In open ground

Planting in groups is often preferred: allow 1 to 4 plants per m2 to create attractive coloured drifts. The lupin is also striking alone in the middle of the short grass meadow.

• Dig a hole 2 to 3 times the volume of the bucket
• Fork the soil deeply
• Add river sand, clay pebbles OR gravel to the bottom of the hole
• Backfill with 1/3 garden soil, 1/3 well-rotted compost and 1/3 potting compost
• Plant the collar at soil level. Firm and water well with rainwater
• Apply organic or mineral mulch

How to plant a lupin in a pot

The less vigorous Lupin varieties tolerate being grown in a pot provided they are repotted every two years into a pot one and a half times larger than the previous one, because Lupin roots tend to circle the pot (chignonnage).

Plant lupin in a mix that is both rich and very free-draining to prevent moisture from stagnating at the roots.

• In a pot of at least 50 cm diameter, lay a good draining layer of gravel or clay pebbles
• Plant in a slightly sandy potting mix
• Water regularly
• Mulch the base

Lupins in situation with evening primroses, roses and peonies (photo PAP)

When and how to sow annual lupin?

Sowing outdoors

Annual lupin seeds are among easiest to sow. Only start sowing once soil has warmed up, directly in ground in April–May. Flowering will then occur only the following year.

• Sow in a « poquet » of 3 lupin seeds per hole at 5–6 mm depth, spacing 20–30 cm apart
• Keep soil moist during germination
• Sowings emerge after 18–25 days
• Keep only strongest young plants

Under cover

It is also possible to sow your lupin seeds under cover in autumn.

• In buckets, sow in groups of 3 seeds
• Cover seeds with a few millimetres of potting compost
• Keep in light and warm conditions
• In spring, plant young plants into pots or in garden without crowding them too closely, as each young plant will quickly take up space.

Learn more in our step-by-step tutorial: How and when to sow lupins?

Maintenance, pruning and care

Undemanding, Lupin requires little care. It is fairly greedy for water: during growing season, give regular waterings to encourage flowering; favour rainwater, lupin dislikes lime-rich water.

Once established, Lupin will tolerate occasional drought. Water only during heatwaves or prolonged drought.

Water potted lupins during summer at least once a week. Repot every two years into a larger pot.

Keep soil cool during growing season to encourage flowering: a mulch to maintain coolness is recommended.

Before winter, in cold regions, mulch the stump at the base.

In poor soil, add compost in March and in autumn to encourage profuse flowering.

Remove faded flowers to encourage reflowering in autumn.

Cut back flower spikes of perennial lupins as soon as they finish flowering; this will prevent self-seeding that can needlessly exhaust the plant and shorten its lifespan. Keep some seeds to maintain clumps, as lupins live only 4 or 5 years.

Lupin clumps lose vigour over the years and disappear quickly (in 4–5 years): every two or three years, divide stumps to rejuvenate them.

When and how to prune lupins

Pruning is limited to a simple spring tidy. In March, at the start of growth, cut back old foliage by half to encourage new shoots.

Raindrops on a lupin leaf

Diseases and potential pests

Robust, though short-lived, Lupin nevertheless has some well-known enemies.

In spring, protect young foliage from ravenous slugs. Plan a slug-control treatment from February and follow our tips to deter gastropods.

The lupin aphid can disfigure plants and cause leaf mottling: get rid of these pests by spraying soapy water.

In autumn, downy mildew and powdery mildew sometimes attack leaves of perennial lupins, dusting them with a white, felt-like coating. Spray Bordeaux mixture or nettle and horsetail manure preventively and burn affected parts. Discover our fact sheet on combating powdery mildew.

Not serious, rust-coloured, brown or black foliar spots can also damage foliage. As prevention, carry out regular sprays of horsetail decoction. If infection occurs, cut affected leaves and burn them.

In poorly drained soil, perennial lupin will suffer from winter damp, causing root rot.

Propagation

Once well established, Lupin will not like to be disturbed either, division is possible but rather delicate. You can carry out sowing to increase clumps, knowing that lupin generally self-seeds. Sowing takes a long time and flowering colour will be unpredictable!

Follow our advice above to sow lupin seeds.

Division

Division of lupins is a good way to renew your plants. Only divide clumps at least 3 years old.

• In March, use a fork-spade to dig up the clump without damaging fragile roots
• Separate the clump into several divisions, each with roots and shoots; if necessary, use a saw
• Replant each new division immediately.

→ Read also: How to propagate lupins to enhance your garden?

Companion planting with lupins

With its vibrant leading shoots of energy that bring grandeur, balance and colour to borders, the Lupin is easy to pair with a large number of annuals or summer-flowering perennials. It makes its mark in all natural gardens to create displays as exuberant as they are fleeting.

Highly structuring, its majestic clusters of flowers are centrepieces of English cottage gardens and herbaceous borders. It is useful to structure natural meadows, valuable for introducing vertical accents and focal points at the back of a border, in edges or large containers near the house.

An idea for a combination: Lupinus ‘West Country Masterpiece’, Cirsium rivulare ‘Atropurpureum’, Iris germanica ‘Blue Crusader’, Salvia nemorosa ‘Caradonna’, Verbascum ‘Southern Charm’, Camassia leichtlinii ‘Caerulea’, Geranium macrorrhizum ‘Bevan’s Variety’ and Aquilegia ‘Clementine Dark Purple’

Its presence also helps to balance volumes in lush borders. The upright habit and the pure or soft colours of lupin lend themselves to every whim.

It is also a staple of white gardens, pink, mauve or purple schemes or blue gardens.

Perennial or annual lupin is perfect for playing on contrasts or nuances in subtle monochrome schemes or in complementary harmonies such as pink/green, for example.

In a rich, romantic scene, against a backdrop of old roses, mix a few clumps of white or pastel lupins with Astrantias, foxgloves, gauras and lavenders.

In a generous scheme where pink prevails, dare the vibrant pairing of a pink lupin with corn poppies, peonies, Oriental poppies, perennial sweet peas.

A tone-on-tone example: Cornus controversa ‘Variegata’, Lupinus ‘La Demoiselle’, Miscanthus sinensis ‘Rigoletto’ (variety close to ‘Morning Bright’ or ‘Variegatus’) / Landscape designer Yvonne Innes – Photo credit Nicole and Patrick Mioulane /

The flattened or globular flowerheads of euphorbias, achilleas or ornamental alliums will lend themselves to striking shape contrasts alongside lupins’ slender spikes.

To crown a natural meadow, among clumps of lupins, plant, leaving enough room for them, hollyhocks, foxgloves, thistles, galegas, cornflowers, veronicas, daisies, cosmos.

Spectacular at the back of an opulent border alongside delphiniums, provide it in counterpoint with light grasses of soft or linear forms and offer it a smoke tree with purple foliage as backdrop.

To give breath and originality to summer containers, surround lupin with other perennials or annuals flowering in summer; dwarf campanulas, arums, verbenas, hardy geraniums, coreopsis, lobelias, petunias or salvias.