Silvery lupine

Sun

Full sun; tolerates light afternoon shade, especially in warmer inland gardens.

Water

Low once established; water young plants regularly, then water deeply during prolonged dry spells rather than keeping the soil constantly moist.

Soil

Well-drained sandy, gravelly or light loamy soil of low to moderate fertility; avoid waterlogged ground and heavily enriched beds.

Height

1-3 ft (0.3-0.9 m)

Spread

1-2 ft (0.3-0.6 m)

Flowers

Late spring to midsummer, later at high elevations; usually blue to violet, occasionally pale pink or white.

Foliage

Palmate leaves with several narrow leaflets, green to silvery grey depending on their covering of fine hairs.

Growth

Moderate; seed-grown plants may take until their second year to flower.

Care needed

Low

• Pollinators
• Deer resistant
• Drought tolerant
• Cold hardy
• Wildlife
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   1.3 ft (0.4 m)

3. After 2 years

   1.6 ft (0.5 m)

4. After 3 years

   2 ft (0.6 m)

   full size

About 3 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Toxic

Native to

the US and Canada

Growth rate

Moderate

• Plant small, young plants in their final positions; the deep root system resents disturbance.
• Water through the first growing season whenever the root zone becomes dry, allowing it to drain between waterings.
• Avoid routine nitrogen feeding and rich manure; this legume can fix nitrogen through root-associated bacteria.
• Use a light gravel mulch where needed, keeping the crown uncovered.
• Do not divide established clumps; raise replacements from seed.

Pruning. Cut spent flower spikes back to the leafy growth after flowering, leaving a few if you want seed. Remove dead stems in late winter or early spring before new growth develops.

Autumn

Sow seed outdoors in a prepared, free-draining seedbed or deep pots; protect pots from prolonged saturation.

Late winter

Remove dead stems and check that fallen leaves or mulch are not covering the crown.

Spring

Plant young plants before hot weather and water them in thoroughly.

Late spring

Check new shoots and flower spikes for aphids; wash small colonies off with water.

Summer

Deadhead fading spikes or retain a few pods for seed; water established plants only during extended drought.

Late summer

Collect dry, browning pods before they split. These seasonal timings follow the Northern Hemisphere; shift them by about six months in Australia.

• Plant in a western North American meadow with native bunchgrasses for vertical flowers above a loose grassy matrix.
• Repeat small groups through a sunny gravel garden, where the silvery leaves contrast with stone.
• Pair with yellow-flowered drought-tolerant perennials for a blue-and-yellow late-spring display.
• Use on a well-drained sunny bank where its deep roots can develop without later disturbance.

Garden styles it suits: Native meadow, Wildflower, Pollinator garden, Dry gravel garden, Desert / xeriscape and Mountain lodge.

Plant it with: Blue grama, Prairie Junegrass, Sulphur buckwheat, Blanket flower, Yarrow and Rocky Mountain penstemon.

Wildlife: Flowers provide pollen for bees, particularly bumblebees. The foliage can feed butterfly and moth larvae, although the species using it vary by region.

• Root or crown rot in wet soil: improve drainage before planting or choose another site; avoid frequent irrigation around established crowns.
• Aphids on young shoots and flower spikes: dislodge with water and encourage ladybirds and other predators.
• Powdery mildew: provide sun and airflow, avoid crowding, and remove badly affected foliage.
• Poor establishment after transplanting: use young plants or sow directly, and avoid breaking or bending the main root.

Treat as toxic to people, cats, dogs and horses. All parts can contain poisonous quinolizidine alkaloids, with seeds and pods a particular concern; substantial ingestion can cause serious neurological illness and may be fatal. Keep it out of grazing areas and seek urgent medical or veterinary advice after suspected ingestion.

• Large-leaved lupine (Lupinus polyphyllus)

  Usually has much larger leaves with more numerous, broader leaflets and taller, denser flower spikes; its foliage is generally greener and less silvery. Silvery lupine is variable, so leaf size alone is not conclusive.

• Silky lupine (Lupinus sericeus)

  Typically has densely silky hairs on both leaf surfaces, while silvery lupine often has a greener, less hairy upper surface.

The epithet argenteus means silvery in Latin and refers to the fine hairs that give the foliage its pale sheen.

Propagation. Grow from seed, preferably from a source suited to your climate. For spring sowing, lightly nick the hard seed coat away from the embryo or gently abrade it, then soak overnight and sow promptly in deep pots or directly outdoors. Plant seedlings out while young; established plants are difficult to divide or move.

Accepted botanical name

Lupinus argenteus

In the US and Canada

Native in Canada and the lower 48 states.

Native range

Arizona, British Columbia, California, Colorado, Idaho, Mexico Northeast, Mexico Northwest, Montana, Nebraska, Nevada, New Mexico and North Dakota.

Measured

Soil pH 7 to 8. Average height 38 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.