Hubrichtii Amsonia
Steel-Blue Spring Flowers and Spectacular Golden Fall Color
Threadleaf Bluestar (Amsonia hubrichtii) is a three-season standout that earned Perennial Plant of the Year honors. Clusters of soft steel-blue, star-shaped flowers top the plant in late spring, the fine, thread-like green foliage forms a soft, ferny mound all summer, and then the whole plant turns a blazing golden-amber in fall that rivals any shrub. Tough, drought-tolerant, and deer-resistant once established, it's a low-care anchor for sunny borders in Eden Prairie, Plymouth, and Eagan.
| Attribute | Detail |
|---|---|
| Botanical Name | Amsonia hubrichtii |
| Mature Size | 2.5–3 ft tall and wide |
| Hardiness Zone | Zone 4–9 (hardy across most of Minnesota) |
| Light | Full sun to part shade (best fall color in sun) |
| Bloom Time | Late spring |
| Flower Color | Soft steel-blue stars |
| Soil | Average, well-drained; tolerates drought once established |
Landscape Uses
Use Threadleaf Bluestar as a specimen, in mixed and pollinator borders, prairie-style plantings, and mass plantings where its fall color can shine. Its ferny texture pairs beautifully with coneflowers, grasses, and bold-leaved perennials.
Best Time to Plant
Plant in spring or early fall, when cooler weather and steady moisture help roots establish.
How to Plant
Dig a hole twice as wide as the root ball and just as deep. Set the crown level with the soil, backfill, water in well, and mulch 2–3 inches deep, keeping mulch off the stems.
Watering
First Year: Water deeply 1–2 times per week to establish the roots.
After Year One: Water during dry spells. It's quite drought tolerant once established.
Drip Irrigation: A drip line provides efficient moisture during establishment.
Frequently Asked Questions
What makes Amsonia special?
It offers three seasons of interest: blue spring flowers, ferny summer foliage, and brilliant golden fall color.
Does it need full sun?
It grows in sun to part shade, but full sun produces the most intense fall color.
Is it hardy in Minnesota?
Yes, hardy to Zone 4 and reliable across most of the state.
Is it deer resistant?
Yes, the milky sap makes it unappealing to deer.
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Pair Threadleaf Bluestar with coneflowers, ornamental grasses, and our compact Blue Ice Amsonia for a textural, low-care border.