String Theory is a compact version of the popular Arkansas blue star, with the same fine, thread-like foliage and brilliant golden orange fall color in a more manageable size. In late spring the mound is covered with light periwinkle blue flowers.
Its dark green leaves stay healthy and green through the summer rather than yellowing, and it blooms a little later than other blue stars. At two to two and a half feet tall, it suits borders, prairie plantings and mass plantings. It is native, easy to care for, heat and humidity tolerant, and deer resistant.
What it looks like
Clusters of small, star-shaped flowers about half an inch across in light periwinkle blue at the tips of the stems. Leaves are very narrow, thread-like and dark green, densely lining upright stems for a fine, feathery texture. The plant is a compact, rounded mound 24 to 30 inches tall and 32 to 36 inches wide. In fall the entire mound turns brilliant golden orange.
Growing it with lavender
String Theory tolerates sun and lean soil once established, and its fine, feathery texture contrasts nicely with lavender's spikes in summer before turning golden orange in fall.
Care
Grow in full sun to part shade in average soil with regular moisture; it tolerates poorer soil and is heat and humidity tolerant. Hardy in USDA zones 4-9. Trim stems back by about a third after flowering to keep the mound full; established plants rarely need dividing.
At a glance
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Botanical name: Amsonia
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Flower color: Light periwinkle blue
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Foliage: Dark green, golden orange in fall
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Growth habit: Compact, rounded, fine-textured mound
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Mature size: 24–30 in tall × 32–36 in wide
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USDA hardiness zones: 4–9
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Light: full sun, part sun to part shade
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Bloom start: Late-May
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Peak bloom: Early-June
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Bloom pattern: Single Flush
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Deer resistance: Resistant
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Pollinator value: Good
Sizes and shipping
Dormant bare-root plant, sold in boxes of 25 per variety (order in multiples of 25). Bare-root plants ship or are picked up March 1–May 31 only. They are soil-free, so they may ship to every state in that window. Dormant plants often show little or no top growth on arrival; plant or heel them in promptly.
Lavender companion · grow guide
Community Grower Report
