Eastern bluestar

Sun

Full sun to partial shade; the strongest stems and best autumn colour usually develop in full sun.

Water

Moderate; keep evenly moist while establishing, then water during prolonged dry spells. Established plants tolerate some drought.

Soil

Average, well-drained soil that retains some moisture; tolerates clay if it is not persistently waterlogged.

Height

2-3 ft (0.6-0.9 m)

Spread

2-3 ft (0.6-0.9 m)

Flowers

Late spring to early summer; clusters of pale blue, star-shaped flowers.

Foliage

Narrowly oval to lance-shaped green leaves on upright stems, turning yellow in autumn.

Growth

Moderate once established; slow in its first season.

Care needed

Low

• Pollinators
• Deer resistant
• Drought tolerant
• Cold hardy
• Heat tolerant
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Very tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   1.4 ft (0.42 m)

3. After 2 years

   1.7 ft (0.53 m)

4. After 3 years

   2.1 ft (0.65 m)

5. After 5 years

   2.5 ft (0.75 m)

   full size

About 4 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Mildly toxic: may upset a stomach

Native to

the US

Growth rate

Slow

• Water deeply during the first growing season whenever the soil begins to dry.
• Apply a thin layer of compost in spring; avoid heavy nitrogen feeding, which encourages floppy growth.
• Mulch around the clump to conserve moisture, keeping mulch away from emerging shoots.
• Use a discreet support before flowering if stems lean in partial shade.
• Leave established clumps undisturbed unless you need to move or propagate them.

Pruning. Cut dead stems to near ground level in late winter or early spring before new shoots grow. If plants flop, shorten stems by up to one-third immediately after flowering to encourage a more compact mound.

Late winter

Cut down last year's dead stems before new growth emerges.

Spring

Plant or divide clumps, water thoroughly and apply a light compost mulch.

Late spring

Check for leaning stems and add support where needed.

Early summer

After flowering, shorten floppy stems if necessary; leave them uncut if you want seedpods.

Summer

Water during prolonged drought, especially in the first year.

Autumn

Leave foliage standing while it turns yellow; collect ripe seed if wanted.

• Plant in repeated groups through a mixed border for blue spring flowers and rounded summer structure.
• Pair with ornamental grasses and coneflowers in naturalistic planting, where its yellow autumn foliage extends the season.
• Use along a sunny woodland edge with ferns and hardy geraniums, allowing for a looser habit in shade.
• Place behind lower spring-flowering plants so its later foliage fills the border after their flowers fade.

Garden styles it suits: New perennial (prairie), Cottage garden, Woodland, Wildlife garden, Low-maintenance and Autumn colour.

Plant it with: Purple coneflower, Switchgrass, Black-eyed Susan, Hardy geranium, Siberian iris and Lady fern.

Wildlife: Flowers provide nectar for visiting insects, including butterflies and bees. Deer and rabbits usually leave the foliage alone, although no plant is completely browsing-proof.

• Floppy stems in shade or rich soil: provide more sun, reduce feeding and shorten stems after flowering.
• Root or crown rot in waterlogged soil: improve drainage or move the plant to a better-drained position.
• Leaf scorch during prolonged drought: water deeply and mulch to reduce drying.
• Occasional rust or leaf spots: remove badly affected foliage, improve airflow and avoid wetting leaves when watering.

The milky sap can irritate skin, and eating plant material may cause stomach upset. Treat all parts as potentially harmful to people, cats, dogs and horses; species-specific poisoning evidence and the severity of risk are poorly documented. Wear gloves when cutting stems and prevent pets or livestock from eating it.

• Threadleaf bluestar (Amsonia hubrichtii)

  Has very fine, threadlike leaves rather than the broader, lance-shaped leaves of Eastern bluestar.

• Shining bluestar (Amsonia illustris)

  Usually has noticeably glossy, leathery leaves; Eastern bluestar leaves are generally duller and less leathery.

Bluestar refers to the pale blue flowers, whose five pointed lobes form a star.

Propagation. Divide substantial clumps in early spring, using a sharp spade through the tough root crown. Alternatively, sow fresh seed outdoors in autumn so winter cold helps break dormancy; germination can be slow and uneven.

Accepted botanical name

Amsonia tabernaemontana

In the US and Canada

Native in the lower 48 states.

Native range

Alabama, Arkansas, Delaware, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Missouri and Nevada.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.