Product Field NotesCompanion Plants
String Theory Blue Star: Feathery Texture and Golden Fall Color
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String Theory blue star is a compact take on the much-loved Arkansas blue star. It has the same very narrow, threadlike dark green leaves lining upright stems, which gives the whole plant a soft, feathery texture, but in a size that fits a home border.
In late spring the mound is dotted with light periwinkle blue stars. In fall the entire plant turns brilliant golden orange, which is when neighbors start asking what it is.
String Theory at a glance
| Trait | What to expect |
|---|---|
| Botanical name | Amsonia 'String Theory' |
| Flowers | Light periwinkle blue stars, about 1/2 inch |
| Foliage | Threadlike, dark green; golden orange in fall |
| Size | 24 to 30 inches tall, 32 to 36 inches wide |
| Bloom | Starts late May, peaks early June, about four weeks |
| Hardiness | USDA zones 4 to 9 |
| Light | Full sun to part shade |
| Deer | Resistant |
Three seasons beside lavender
Spring: periwinkle stars open in late May and early June, a little later than many blue stars, bridging the gap before lavender comes into color.
Summer: the fine green foliage stays healthy rather than yellowing, and its billowy, rounded shape contrasts nicely with lavender's upright spikes. Green threads behind silver-gray lavender read as calm and cool on a hot July day.
Fall: once the lavender has been cut back to tidy mounds, String Theory lights up golden orange. That gives a lavender bed a second season of interest without adding a single extra chore.
It tolerates sun and lean soil once established, but it appreciates more regular moisture than lavender. Plant it behind or beside your lavender rather than in the driest spot, leaving about three feet for its width. The Companion Plant Planner helps you place it.
Care through the year
- Site: full sun to part shade; full sun gives the best fall color.
- Water: regular moisture while it establishes, then it handles heat and humidity well.
- After bloom: trim stems back by about a third to keep the mound full.
- Fall to spring: fully hardy and long-lived in Michigan. Enjoy the fall color, then cut back in late fall or early spring.
- Dividing: established plants rarely need it.
Pests and diseases are few, with only occasional rust or leaf spot. Wear gloves when trimming; the milky sap may irritate skin.
Plug trays or bare root
String Theory is offered as a 72-cell plug tray and as a bare root plant. See each product page for current availability, or the Wholesale Hub for tray orders.
Frequently asked questions
How big does it get compared with standard Arkansas blue star?
It is shorter, denser and more upright, topping out around 24 to 30 inches tall, which makes it easier to fit into a border.
Is it a native plant?
It is a selection of a native North American blue star, at home in native gardens and prairie-style plantings.
Can I grow it in a container?
Yes, containers are one of its listed uses. Choose a large pot so it has room to fill out.
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