Lupinus perennis (Sundial lupine)
Lupine flowers

Zone: 3 to 8

Soil: sand to sandy loam

Light: Full sun to part sun

Bloom colour: Mostly blue

Bloom period: June

Height: 1 to 3 feet

Moisture: Dry to medium

Attracts: Bees and butterflies.

Notes: Lupines are exquisite garden plants in their own right with flowerheads about a foot high. There is only one species in Ontario, which is native to the Eastern half of North America. The Sundial Lupine is a tough plant that will grow in dry, sandy, slightly acidic and nutrient-poor soil; however, it is not a versatile plant as it will not grow well in any other conditions. If you do not have the right soil type, consider planting Baptisia sp. instead. Lupines are nitrogen fixers and exemplify the bacterial processes that dominate the nutrient cycling in sandy soils.

Lupines have a large terminal spike of flowers that will be around for a few weeks during June. Hover flies are not strong enough to push into the flowers and it requires bees for pollination. If successful pollination occurs, you will notice the seed pods within a couple of weeks.

Lupines grow well in full sun, but these are the same conditions in which the Lupine aphid also thrives. These aphids will wreck the plant by causing the leaves to break off and by preventing the plants from forming seed pods. If this aphid is affecting your lupines, then you need to move the lupines to a place where they only get a few hours of afternoon sun each day. This is the most effective way to avoid issues with these insects. When you try to remove the aphids mechanically, a large number of them just jump off the plant and come back when you are not looking.

Lupines will reproduce using rhizomes and by self seeding. In suitable conditions it can become a dominant perennial where it will provide a sensational flower show for a few weeks accompanied by an intoxicating fragrance and the din of buzzing bees. You can start a colony of lupines by sewing seeds in the fall. No other scarification is needed.

In Ontario, this plant has become rare and as a result, the Karner Blue butterfly, which relies on lupines exclusively as a host plant, has become extirpated in the province. It is important to ensure that your source of seeds is the actual native lupine. Russell hybrids readily hybridise with Lupinus perennis and can contaminate the gene pool of this native species, rendering it inedible to the Karner blue butterfly. Russell hybrids readily escape into the wild in several parts of the world including Canada.

The large flowerheads of the Sundial Lupine
A bee getting into a lupine flower
Bees can force their way into the flowers
The individual flowers are pea like.
A field of lupines
A large field of hybrid Lupines that have escaped cultivation,
Lupines with their palmate leaves Lupine seed pods
Lupines with their palmate leaves Lupine seed pods