Physostegia angustifolia aka Narrow Leaf False Dragonhead

Physostegia angustifolia belongs to the mint family, Lamiaceae. This perennial lives for more than two years. Its names include obedient plant and narrowleaf obedience plant. It comes from the central and southeastern United States. In Missouri, it grows in the Ozarks. It also grows in prairie areas that glaciers did not cover. Kew places it in a temperate climate. It is not native to Britain or Ireland.

This plant grows upright in clumps. It spreads through rhizomes, which are stems that grow underground. Garden plants reach 2–4 feet [0.61–1.22 metres] tall. Their spread can reach 3 feet [0.91 metres]. The square stems are a mint family trait. Its narrow leaves help tell it apart from Physostegia virginiana. Its stems also tend to be stiffer than that species. Even so, garden plants can lean or fall. Rich soil and too much shade raise this risk.

Pink flowers form spikes at the tips of stems. Each bloom has a shape much like a snapdragon. The spikes last well and add late-summer colour. Missouri Botanical Garden gives August to September as the bloom season. Chicago Botanic Garden gives July through October, a longer span. The showy blooms make good cut flowers for indoor display. They add colour and contrast among other border perennials.

Full sun gives this species the best garden conditions. It can take light shade but may need stem support. Use average soil that drains well and stays moderately moist. Soil with high fertility can make stems flop more. The listed USDA hardiness range is zones 3–9. Missouri Botanical Garden says it is easy to grow. Still, it takes some work to keep its spread in check. Divide clumps every two or three years to limit growth. Leave room for rhizomes to spread past the first clump.

This species suits wildflower gardens, prairie plantings, and meadows. It also suits perennial borders where its spread is welcome. Its strong growth can make it hard to contain. It resists deer, which helps where deer limit plant choices. Sources report no major insect or disease concerns. Rust can occur, so problems may still arise. Stakes may help hold leaning flower stems upright. The supplied sources give no fruit facts for this species. They give no facts on edible parts for this species, either. They offer no basis to judge whether it is toxic.