We grow silky and silvery lupines together; they are very very similar. Unless you strongly desire one species over the other, you will receive one or more of either species (if you do, leave a note at purchase). The description here applies to both species. 
 
Silky lupine is a showy and long-lived perennial whose pale purple blooms cover the hillsides in the spring and summer. They are versatile, growing in prairie and open woodland habitats. Plant them in well-drained soil with full sun or light partial shade. Well-drained soil is a must!
 
Unlike the lupine species you commonly find in nurseries, silky lupine grows a substantial taproot to survive summer drought. Because of this taproot, it is important to plant lupines when they are still quite small (transplanting a taproot, especially one folded up in a container, is not ideal). Your plants will be little with only a couple of leaves; this is by design. Try not to disturb the roots when planting. They will want deep watering every week the first season when they are growing, but if they start to go dormant, don't try to water them "back to life". Just water the area every couple weeks until the fall. Plants will reappear in the spring.
 
Lupines also form a symbiosis with soil bacteria to fix nitrogen (meaning they fertilize the soil around them).  They do well in low nutrient rocky soil, and play an important role in rehabbing disturbed sites. 
 
Our young lupines will need some extra TLC when establishing, but they will reward you with effortless blooms year after year. They are well-behaved in a garden setting, and provide a nice focal point in spring/early summer. Since they go dormant later in the season, plant with bunchgrasses, antennaria, or later bloomers like hairy golden aster to fill the void.