time is May-July.   Silvery Lupine (Lupinus argenteus) Stems are 20-40 inches tall, flat-hairy to almost silky, often grayish-hairy. Flowers are 9-11 mm long. The calyx is flat-silky-hairy. The banner is mostly hairless. Leaves have 6-9 leaflets and are hairless above to short-flat-hairy on both surfaces. Flowering time is May-July. According