Called bluebonnets in Texas where they are the state flower and lupines nearly everywhere else, the Lupinus genus encompasses 600 or more species worldwide. Most commonly a rich blue shade, lupine blooms appear from March to April above rosette-shaped leaf clusters that are relatively pest-free and adaptable to many soils. When you plant scarified seed (treated with acid to allow water to penetrate the hard seed coat) in the fall, the next spring you will be rewarded with lovely flowers capable of reseeding themselves.
Probably the main reason to grow bluebonnets is for the sheer joy of seeing a field of them bursting into bloom in early spring. Not all varieties have blue flowers. New cultivars may have white, red, pink, yellow or even bicolor blossoms and a longer blooming season, lasting till late summer or even autumn. This is especially true of the New Generation hybrids, developed from the classic Russell hybrids but sturdier and only requiring replacement every seven to eight years in U.S. Department of Agriculture planting zones 5 to 10a. Several colors of lupine blooms planted together should delight any landscape designer.
As a legume, bluebonnets have roots that work with a bacterium called Rhizobium to improve plant growth and flowering. Rhizobium converts atmospheric nitrogen to a form that plants can use. Perhaps because of the Rhizobium, fertilizing lupines is not recommended, as it can encourage leggy and weak plants with few flowers. The nitrogen fixation process enriches the soil for other plants, as well as next year's lupine crop.
Lupines of all species are nectar plants that feed birds. The California quail, in particular, loves the silver lupine (L. argenteus) that is a perennial in zones 5 to 8. Butterfly larvae rely on lupines for food, too, bringing beauty and motion to your garden. On the other hand, deer do not like the taste of bluebonnets and will avoid them, keeping destruction away from your plantings.
Benefits Beyond the Home Garden
Processing lupine seed for feed for cattle and poultry is a significant new commercial venture. In Europe, lupines are being cultivated for animal feed because their seeds contain the full range of essential amino acids. Because they grow in cooler climates than soybeans, they are reportedly gaining worldwide popularity as a substitute for soy, previously the most commonly planted feed crop.
- Learn2Grow: Everything's Better With Bluebonnets on It!
- The New Sunset Western Garden Book; Kathleen Norris Brenzel
- Lady Bird Johnson Wildflower Center: How to Grow Bluebonnets
- Las Pilitas Nursery: California Birds in Your Native Plant Garden
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