Lupinus spectabilis is a hairy annual herb growing 20 to 60 centimeters tall. Each palmate leaf is made up of usually 9 leaflets measuring 1 to 4 centimeters in length. The inflorescence bears whorls of flowers each just over a centimeter in length. The flower is usually blue with a white patch on its banner, but all-white flowers have been noted. The fruit is a very hairy legume pod up to 5 centimeters long.