Thermopsis caroliniana
Carolina or Southern lupine

June is one of my favorite garden times when spiky perennials, like lupines, foxgloves, and mulleins punctuate our borders with torches of color. Thermopsis caroliniana (or villosa depending on what taxonomist you follow) is making its bold color statement at the nursery entrance right now and will continue for another week or so.

Thermopsis closely resembles lupines or baptisias, although botanically it is neither. Native to the mountains of North Carolina, Thermopsis performs beautifully where true lupines don’t–because of heat and other conditions. Clean compound foliage rises 3 to 4 feet with spikes of bright sulphur-yellow, pea-like flowers during June in the Hudson Valley. The flower color is bold and guaranteed to attract attention. I love to mass Thermopsis next to ornamental grasses, like the blue-bladed Panicum virgatum ‘Dallas Blues’ (pictured), to tone down its fluorescent bloom.

My other pitch for this perennial is post-flowering, when architectural seed pods develop. Don’t cut it back after bloom, as suggested in lots of books and internet searches. After shedding seed, gray-brown receptacles ride through winter on sturdy leafless stems. They are great for indoor arrangements or against snow in winter. Now that’s a four-season, four-star perennial!

Culture: full sun; plants clump and reseed, but not aggressively; USDA zone 4-8.