How To Grow Lupines From Seed: 9 Expert Growing Tips
Lupines—favorite wildflowers with striking bell spikes and sweeps of warm season color—are easy to grow from seed in the right conditions. Seedlings get underway with a few steps to promote successful germination. Garden expert Katherine Rowe explores how to grow lupines from seed for bright, perennial blooms.
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Lupine charms the warm season landscape with bell blooms that crowd upright stems in blues, purples, pinks, whites, yellows, and bicolors. The Lupinus genus holds over 300 species, many native to North America and the Western region, in particular.
The native wildflowers and favorite cultivars are easy to grow from seed with a few steps toward the best germination. Start them in late fall, winter, or early spring to enjoy the short-lived perennials and their seasons of recurrent color through self-seeding.
Growing Lupines From Seed
Lupine seeds are large and easy to work with. They have a thick, protective seed coat around an embryonic root, stem, and leaves. They also have a nutrition-packed food supply in the endosperm that nourishes the seed for growth.
As water and oxygen penetrate the seed coat, the internal embryo develops, and the seed coat breaks open. The root emerges first, and then the stem with seed leaves (cotyledon). The seedling uses the nutritional stores to grow and form true leaves, and photosynthesis gets underway.
The protective seed coat allows the seeds to endure until conditions favor sprouting, laying dormant even in snow and freezing conditions and through drought and extreme heat.
Lupines develop strong taproots sensitive to disturbance at transplanting. Direct sowing seeds in their permanent location avoids potential damage. To start seeds indoors or in winter-sown containers, plant them in biodegradable pots or soil blocks, or transplant them before extensive roots develop.
Select the Species and Varieties
Lupines are hardy in USDA growing zones 3-8, where they perform well in cool climates as short-lived perennials. They take time to establish but often reseed once they do.
Lupinus perennis, or wild lupine, is native to eastern North America. Sky-blue flowers line multiple spikes up to eight inches long. Flowers are often two tones of purple and blue or blue and white atop attractive palmate leaves.
Meadow lupine (Lupinus polyphyllus) is one of the showiest species, with dense violet bloom spikes and a cushion of blue-green leaves. It’s robust at three to five feet tall with vigorous growth and adaptability. This adaptability led to invasive qualities outside its native Western range, particularly in the northeastern U.S. In its Western native range, it plays a vital role in ecosystem management regarding erosion control, soil improvement, and pollinator resources.
Bluebonnets, the famed state flower of Texas, is another lupine species (L. texensis). In spring, these emerge in waves along hillsides and fields. The rich blues kickstart a celebration of the season.
In addition to the straight species are ornamental hybrids tailored to the home garden and good performance. The Russell hybrids are a top-performing series with petal-packed stems, stout and upright, and with reliable flowering. The long-lived favorites are an heirloom cross from 1937 and remain one of the best to grow from seed today.
Choose the Best Site
These graceful wildflowers have a rugged constitution and grow in a variety of conditions – from dry to moist, hot to cold, and in lean soils. The wild beauties are legumes, meaning they have a symbiotic relationship with bacteria that fix nitrogen in the soil and improve surrounding soil nutrition.
The most vigorous growth and flowering occur in neutral to slightly alkaline soils and cool conditions with regular moisture. They prefer coarse, loose soils with good aeration and drainage. Full sun to partial shade, with six or more hours of daily sunlight, is ideal. In cold climates, provide a mulch layer to promote overwintering.
Stratify and Scarify
For successful germination, lupine seeds benefit from cold, moist stratification. To hasten the process, scarification through soaking and nicking helps.
Cold Stratification
Cold stratification triggers seeds to break internal dormancy. The interior tissues need exposure to moisture and freeze and thaw conditions. Cold temperatures for several weeks, followed by a warming spell, initiate sprouting.
Stratification occurs naturally in cool climates by direct-sowing seeds in the fall or winter. In cold climates, lupines receive the stratification with an early spring sowing. They receive the necessary exposure to cold temperatures followed by spring’s warmth, which indicates favorable growing conditions. In mild climates or to start seeds indoors before transplanting, mimic the cold period by putting seeds in the refrigerator before sowing.
Scarification
When starting lupine indoors or outside post-frost, seeds benefit from scarification. Scarifying accelerates what naturally occurs during cold stratification by softening the seed coat. To scarify lupine, make a small nick in the coat or rub lightly with medium-grit sandpaper. Soak seeds to soften before planting for a couple of hours until they’re plump.
You can also skip the nicking and opt for a longer soak. Softening and exposing the surface allows water and oxygen to penetrate the exposed areas and reach the central embryo. This signals that spring is coming and conditions are right for growth.
Use a sharp blade or nail clippers to nick the coating or clip the corner of the seed. Creating an opening makes it easy for the sprout to spring into action when it meets moisture and growing media. Clip only the outer seed covering to avoid damaging the interior.
Direct Sow
As early as December, you can sow lupine, either directly on the ground or in protective containers. In cold climates, this extends into March. Climate and temperature affect germination, and starting in freezing conditions ensures seeds get their cold stratification.
Direct sowing is the easiest way to sow lupine seeds. With scattering them in place in cold weather, they germinate in spring’s mild conditions after exposure to natural freeze and thaw cycles.
Sow lupine seeds by scattering them in fall or winter, covering lightly with soil (⅛ inch deep). Snowfall helps by providing insulation until seeds germinate in the spring. If you miss winter or early spring sow, wait until one to two weeks after your final frost in spring to seed outside. With direct sowing, there’s no need for the extra scarifying due to seasonal exposure.
Winter Sowing
Lupines show high success rates with winter sowing in protective containers to expose seeds to natural conditions while warming the ambient air. In the outdoor containers, the seeds receive all they need to germinate (light, water, oxygen, and temperature variation). With a headstart on growth, the seedlings are ready to take off at planting.
In the winter sowing container method, seeds overwinter in homemade “greenhouses” made from repurposed plastic containers. Placed outside, they receive exposure to natural elements. When conditions are favorable, the seedlings sprout, developing strong taproots for vigorous growth and early blooming with no hardening-off period. Winter sowing lupine is straightforward, budget-friendly, and works with the seed’s needs to promote sprouting.
Aim to winter sow lupine about six to eight weeks before you plan to transplant them to the garden bed or outdoor container. In warm zones, the seeds germinate faster. Provide at least several weeks of cool temperatures for cold stratification.
Starting Indoors
While direct sowing provides the least risk of root disturbance, you can sow lupine seeds indoors before moving them outside in spring. Use soil blocking or biodegradable pots to minimize damage to the sensitive roots.
Sow seeds six to eight weeks before the average last frost date. Germination occurs sporadically within two to four weeks or more.
If started indoors, tender seedlings benefit from gradual acclimation from the warmth of indoor growing situations to garden conditions. Before transplanting the young plants, place them in a protected outdoor area for a few days to a week. Slowly move them to conditions mirroring their new garden location.
Protect them from strong winds, cold nights, and afternoon sun in the process. Hardening off sets plants up for success at transplanting.
Thinning, Tending, and Transplanting
Maintain even soil moisture for developing seedlings. As they reach two inches tall, thin them to 12 inches apart (or as recommended by variety). Thinning ensures proper air circulation, root space, and room for maturity. Thin by clipping excess seedlings at their base (rather than pulling and risking root disruption).
Seedlings started indoors or in winterized containers are ready to transplant after exposure to garden conditions. Look for true leaves – the fully developed leaves after the cotyledons – and a few inches of height as indicators of readiness. Take care during transplanting to avoid root disturbance. Capture as much soil and roots as possible for each seedling to minimize disruption. Cut away biodegradable pots or plant it in place.
Use varietal spacing guidelines to position the lupines. Small varieties benefit from a 12-18-inch spacing, while larger ones need two to three feet apart.
Collecting Seeds
In mid to late summer, long pea-like seed pods emerge and mature. Lupines reseed naturally under optimal conditions, and the seeds are easy to collect. To harvest fresh seeds, leave them on the stem until they transition from green to gray-brown. Pick the pods and snap them open to easily expose the seeds. Direct sow them in their new location, following sowing guidelines.
The seeds will receive the cold stratification and scarification necessary for germination in the spring. You may not see blooms from the new generation until the following year, but the population is in place for continued color.
