Ask Mr. Smarty Plants

Sorry for the delay in answering your question. Texas bluebonnets (Lupinus texensis) are a wonderful sight in the spring across the ranch fields and gardens of Texas. Glad that you are trying to bring some of the bluebonnet magic to Missouri.

Texas lupine has larger, more sharply pointed leaves and more numerous flower heads than similar lupines. Light-green, velvety, palmately compound leaves (usually five leaflets) are born from branching, 6-18 in. stems. These stems are topped by clusters of up to 50 fragrant, blue, pea-like flowers. The tip of the cluster is conspicuously white.

This is the species often planted by highway departments and garden clubs and is one of the six Lupinus species which are the state flower of Texas.

Not only does the state flower of Texas bloom oceans of blue, but this famous wildflower forms attractive rosettes in winter. This is the species often used by highway departments and garden clubs. If planting this species in areas where it has not formerly grown, it may be helpful to inoculate the soil with a rhizobium (soil-borne bacteria which form nitrogen-rich root nodules) for lupines.

Since bluebonnets prefer limestone/chalky, sandy loam, limestone-based, sandy, medium loam soils, your turface and sand mix should work well with a low percentage of compost or loam added to it.

The Texas Department of Transportation has a good information sheet online about starting bluebonnets from seed. Bluebonnets produce large, hard-coated seeds that may cause them to have a low germination rate the first year or two. As the hard seed coats wear down by rain, abrasion and decay, the seedlings begin to sprout. Bluebonnets grow best in soils that are alkaline, moderate in fertility, and most important of all, well drained. Full sun is also required for best growth. After seeding, it is best to cover the seed with soil no more than one-quarter inch deep. This protects the seed from being eaten by birds or "baked" by the sun. Water thoroughly but gently. Follow the first watering with additional light waterings every three days for about three weeks if rain is not present. Be aware that one of the reasons bluebonnets fail to bloom is the lack of an essential bacterium in the soil. These bacterium known as rhizobium form nodules on the roots of the bluebonnet plant and are able to fix atmospheric nitrogen (this is the conversion of atmospheric nitrogen to a form usable by plants). This nitrogen fixation is needed for the bluebonnets to bloom.