Lupines are members of the bean family and, like many legumes, are fixers of nitrogen in the soil. In areas of the country to which they are alien, they have become invasive, changing the soil so dramatically that native plants can't survive. Some lupines that are native to the Sacramento valley that thrive in its Mediterranean climate. Most lupine plants have large taproots so they need well-drained soil. In fact, they do great in sand. Do not over-water and look out for aphids, as they are especially attracted to lupines.
If you see a Sacramento valley field that appears to be blue, it is no doubt home to the valley sky lupine (Lupinus nanus). This California native is an annual herb found in valley grasslands where it receives 20 to 25 inches of rain a year. The valley sky lupine will grow from 8 inches to 1 foot in height with stalks of blue flowers. This pretty blue lupine will grow in sand or clay and requires nothing more than lots of sunshine and somewhat dry soil between waterings.
The silver lupine (Lupinus albifrons) is a 3 to 5 foot high, silvery-colored perennial shrub. Another blue-flowering California native, it thrives in full sun and dry soil. Sacramento valley homeowners can enjoy not only the highly fragrant flowers but the butterflies that the silver lupine will attract into the garden. Silver lupine makes an attractive addition to the native California woodland garden as a contrast to helianthus or California poppies.
Yellow Bush Lupine
The soft yellow, fragrant blooms of the yellow bush lupine (Lupinus arboreus) make it a favorite of Sacramento valley native plant gardens. This 4 to 5 foot perennial shrub blooms tiny, pea-like flowers, on 6 inch stalks in either yellow or blue. The yellow bush lupine is drought and cold-hardy, does well in poor soil and grows quickly. In its natural environment it gets 15 inches of rain a year so be careful not to overwater it, plant it in full sun and it will thrive. The yellow bush lupine blooms from March to June in the Sacramento valley.