For native plant enthusiasts, Lupinis perennis is preferable to the Russell hybrids and other hybrid lupins (Lupinis x hybrida) that most people grow as garden plants. Widely known as wild lupine, native lupine, or blue lupine, L. perennis is found across much of eastern North America, as well as along the shorelines of the Arctic Ocean. Once extremely prevalent, its range has been greatly diminished by human development. And because it is an important food source for the caterpillar of several species of threatened butterflies, the plant is receiving new interest as a garden plant and in wild-flower restoration projects.
If wildflower restoration is a goal, never use hybrid lupine seeds for planting in meadows and other wild areas. These plants will quickly revert to their original parent species, which are often non-native. And these "invaders" can crowd out the true native wildflowers, including the L. perennis. Instead, buy seeds for the species that is native to your area.
The native species found in western North America, L. polyphyllus has now spread to eastern North America, but is authentic restortion is your goal, it is best to use whichever species is original to your region—L. perennis in the east, L. polyphyllus in the west.
Wild blue lupine is quite similar to the more gaudy hybrid lupines, with distinctive palmate leaves that are attractive in the garden even when the plant is not blooming. Spiky blue flower racemes 4 to 10 inches tall appear in late spring or early summer on plants up to 2 feet tall. Rather than the piercingly bright candy colors of the hybrid lupines, L. perennis plants generally have more subdued color—generally blue or purple, but occasionally white or pink.
These flowers are herbaceous perennials and members of the pea family. As such, they are nitrogen-fixers.They actually improve the soil in which they're planted. Lupines are generally planted in the spring, either from potted nursery starts or from seeds sown directly in the garden. Nursery plants can be hard to find for wild species, so you may need to buy seeds from a specialty nursery.
Like the hybrid lupines, native L. perennis is a relatively short-lived perennial. It sometimes does not bloom until its second year, and individual plants may live no more than three or four years. But wild lupines self-seeds very freely, and once a patch is established, you will have reliable blooms every year.
|Botanical Name||Lupinis perennis|
|Common Name||Blue lupine, wild lupine, native lupine, sundial lupine|
|Plant Type||Herbaceous perennial|
|Mature Size||12–24 inches tall, 12–18 inches wide|
|Sun Exposure||Full sun|
|Soil Type||Dry to average moisture, well-drained soil|
|Soil pH||5.8 to 6.2 (slightly acidic)|
|Bloom Time||Spring to summer|
|Flower Color||Blue; sometimes white or pinkish|
|Hardiness Zones||3–8 (USDA)|
|Native Area||Eastern North America|
|Toxicity||Toxic to humans and animal|
Wild Blue Lupine Care
This native species is grown much the same as the more common hybrid garden lupines. Lupines, having long taproots, are one of those fussy plants that dislike being transplanted. For this reason, it is better to try to establish them by seeding them directly into the garden. Lupines love cool weather and react badly to the combination of heat and humidity. In fact, some long-time gardeners for whom lupines once thrived are beginning to find that climate change is making the plant harder to grow in their regions, while gardeners in very cool zones are finding newfound delight in lupines.
Lupine normally does best in full sun, but in the southern part of its hardiness range, it appreciates some shade, especially during the heat of the afternoon.
L. perennis does well in dry to medium-moisture soil that is well-drained. It does very well in sandy soils and is often found growing wild in sand dunes and along shorelines. Dense soils can be loosened by digging in humus or peat moss. Lupines prefer a slightly acidic soil, which can be provided by blending in peat moss or another soil amendment, or by feeding with an acidifying fertilizer.
Wild lupines generally will do well with whatever rainfall falls naturally. These are less finicky plants than the hybrid varieties. In drought conditions, however, some irrigation will be helpful.
Temperature and Humidity
Lupines like fairly cool and dry conditions. They may struggle in the southern part of the hardiness range, unless provides with shade and mulch to keep the soil cool. They will thrive in areas with cool, dryish summers.
These are nitrogen-fixing plants that generally don't require feeding. However, alkaline soils can be corrected by feeding with an acidifying fertilizer.
Is Lupine Toxic?
Lupinus perennis is one of the Lupine species that are toxic to humans and animals. All plant parts, but especially the seeds, contain an alkaloid known as D-lupaine, which can be fatal if eaten in very large quantities. The seeds are bitter, however, so serious poisoning is rare except in grazing animals, such as goats and horses.
Symptoms of Poisoning
Symptoms of lupine poisoning in humans and animals include fatigue, a slow heart rate, slowed breathing, and convulsions. If you suspect poisoning, contact your poison control agency or veterinarian immediately.
Related Varieties of Lupine
- There are no named cultivars of L. perennis, but it's sometimes hard to distinguish this species from other wild species.
- Lupinus polyphyllus is another very prevalent North American species, found originally in the west but gradually naturalizing across most of the continent. It is regarded as an invasive plant in part of the Eastern U.S., where it has crowded out other native species. It grows up to 4 feet tall and has blue flowers.
- Lupinus texensis (Texas bluebonnet) is an annual species with deep bluish-purple flowers. It grows 1 foot tall. It freely self-seeds.
- Lupinus luteus (yellow javelin) is a 2-foot-tall annual with yellow flowers. Like other annual species, it is a prolific self-seeder.
- Russel hybrids are a hugely popular commercial variety available in mixed colors. Sometimes categorized as Lupinus x hybrida, these are derived from Lupinus polyphyllus as one parent species. Hybrid lupines are short-lived perennials that grow up to 3 feet tall and are hardy in zones 3 to 7. They have sometimes escaped garden cultivation to naturalize in surrounding areas, where it quickly reverts to its L. polyphyllus parent. This is problematic in areas where L. polyphyllus is not originally a native plant.
Deadheading spent flowers can prolong the bloom season for wild blue lupines. A hard pruning of all leaves may sometimes lead to second flush of growth and blooming.
Propagating Wild Blue Lupines
These are prolific self-seeders, and it is possible to transplant the small volunteer seedlings from the garden. Do this when they are still small, however, as the plants quickly develop deep taproots that resent being dug up. It is also possible to collect the seed pods, remove and dry the seeds, and replant them in desired locations.
How to Grow Wild Blue Lupines from Seed
Because lupines develop long taproots, it is best to seed them directly into the garden in the location you want to grow them. Plant when the soil is warmed in the spring and all danger of frost has passed. Soak the seeds overnight, or scarify them by rubbing them with sandpaper or a nail file, then plant them in the garden about 1/4 inch deep. Water lightly each day until they sprout. They will take 14 to 30 days to germinate and sprout, so be patient.
After frost kills the foliage, cut away and dispose of foliage to remove disease pathogens. Mulching the roots is generally not necessary with these very hardy plants.
Common Pests/ Diseases
As is true of most native wildflowers, L. perennis is very resistant to pests and diseases. The most common pests are aphids, best treated with horticultural soaps or oils. They can also be susceptible to brown spot fungus; remove and destroy affected plants, and avoid using the area to grow lupines for several years so the spores have time to die off.
Powdery mildew can affect lupines, especially if there isn't good air circulation around the plants. It rarely kills plants, but you can cut away the foliage and wait for regrowth, or use a spray fungicide on plants. Powdery mildew infects plants from spores splashing up from the soil, so prevent the disease by carefully soaking the soil rather than by overhead spraying.