PL. —Amsonia rigidaBotanical illustration — drop image
Amsonia rigida

Stiff Bluestar

Spring
6a9bHardiness zone
Peak bloom windowZone 6b · frost-offset weeks
Winter
Not in bloom
Spring
Peak bloom
Summer
Not in bloom
Fall
Not in bloom
Peak bloom
In bloom
Background

Amsonia rigida is a native perennial of the southeastern coastal plain, found from Georgia to Louisiana. It forms upright, clumping stems with narrow leaves and bears clusters of pale blue, star-shaped flowers in spring. Reliable golden-yellow fall foliage adds a second season of interest, making it a strong choice for native plantings and mixed borders.

In its natural range, A. rigida occupies stream margins, wet flatwoods, and seasonally flooded areas. It performs best in consistently moist to wet garden soils and tolerates periodic standing water, setting it apart from other bluestars that prefer well-drained conditions. Plants spread slowly by rhizomes and naturalize into stable clumps over several years. Cutting stems back by about one-third immediately after flowering keeps growth compact. Milky latex throughout the plant deters deer and most browsing mammals.

A. rigida provides early-season nectar to native bees and other pollinators. Its alkaloid-containing tissues, characteristic of the dogbane family (Apocynaceae), support specialist insects that have evolved to tolerate or sequester plant toxins.

Care guide
SunFull sun to part shade
WaterMoist to wet
SoilMoist to wet, loamy, slightly acidic
Spacing24–36 in
Height24–48 in
Zone6a – 9b
Native RegionAL, FL, GA, LA, MS
Frost hardy
Seasonal tasks
spring
watchCheck new growth for aphid colonies; dislodge with a strong water stream if found.
cutRemove dead stems at the base before new growth pushes in early spring.
sowPlant container-grown starts in prepared moist soil around the last frost date.
cutDivide crowded clumps every 3–4 years in early spring before stems exceed a few inches tall.
cutTrim all stems back by one-third immediately after flowering to maintain compact form and prevent flopping.
fall
watchMark plant locations as foliage turns golden yellow in fall before stems die back completely.
Common problems

Rust

Symptoms

Orange to brown raised pustules on the undersides of leaves, with yellow spotting on the upper surface. Heavy infections cause leaves to yellow and drop.

Treatment

Remove and destroy infected leaves. Avoid overhead watering and improve air circulation. Apply a sulfur or copper-based fungicide if it spreads. Clear plant debris in fall.