Lupine plants produce flower spikes as tall as 5 feet in the spring and late summer, providing a striking vertical accent in the landscape. This member of the pea family requires minimal care, and even grows as a wildflower in some parts of the United States.
Many people think of lupines as blue or white flowering plants, as this is the common form of the lupine wildflower. However, gardeners who grow the dwarf ‘Russell’ variety of lupine can add pink, red, and yellow flowers to their lupine bouquet. ‘Tutti Frutti’ is a hybrid that offers bicolor flower tones in the seed mix, including crimson and yellow or purple and magenta.
Lupines are easy to grow from seed for beginning gardeners. The seeds have a tough coat, so soak the seeds in water overnight to hasten germination. Lupine seeds are large enough that gardeners can use scarification to increase germination, which means nicking the seed coat with a knife or abrading it with sandpaper. New lupine plants need one growing season to mature enough to produce blooms, so gardeners may fill in newly planted areas with annuals until the second season blossom show begins.
Gardeners must choose a planting site for lupines with care, as the plants produce long taproots and don’t fare well with transplanting. Lupines grow well in soil that is sandy and fast draining, so clay soil is an unsuitable growing medium. Gardeners with heavy clay soil may grow lupines successfully in raised beds.
Lupines prefer full sun to partially shady conditions. Gardeners who live in USDA planting zones 6 or higher may plant lupines where they can receive afternoon shade, which prolongs the life of the blossoms.
Lupines require average moisture conditions, and the plants will develop root rot if they have constant wet feet. The long taproot indicates a plant that has natural drought tolerance, and lupines thrive with deep, infrequent watering rather than daily shallow watering.
Like other members of the pea family, lupines fix nitrogen, which means they take nitrogen from the air with the help of bacteria, and then return it to the soil. Lupines don’t need additional nitrogen, but they can benefit from a bi-weekly application of seaweed meal, which provides the full range of trace minerals.
Powdery mildew and fungal diseases are a problem for lupines that grow in hot, humid areas. Gardeners can control these diseases by spacing the plants properly for increased air circulation, and by using drip irrigation instead of overhead watering.