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Herbaceous Perennial

Chelone obliqua

twisted shell flower

An erect perennial to 60cm tall, with prominently veined and toothed leaves, and compact spikes of dusky deep pink or purple flowers 2cm long

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Ultimate height

0.5–1 metres

Time to ultimate height

2–5 years

Ultimate spread

0.1–0.5 metres

Clay

Loam

Moisture

Moist but well–drained, Poorly–drained

pH

Acid, Alkaline, Neutral

	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Full sun
Partial shade

Aspect

South–facing or West–facing or North–facing or East–facing

Exposure

Sheltered

Hardiness
Hardiness ratings
All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets
H1a: under glass all year (>15C)
H1b: can be grown outside in the summer (10 - 15)
H1c: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20)

Botanical details

Family: Plantaginaceae
Native to GB / Ireland: No
Foliage: Deciduous
Habit: Bushy
Genus: Chelone are herbaceous perennials with undivided, paired leaves and short terminal spikes of showy, 2-lipped, tubular flowers opening from late summer to early autumn
Name status: Correct
Plant range: USA

How to grow

Cultivation

Grow in deep fertile, moist soil in partial shade or sun. Tolerant of heavy clay soil, may also be grown in a bog garden; apply a deep mulch of organic matter in mid-spring

Propagation

Propagate by seed sown in containers in a cold frame in early spring; by division in spring; root soft tip cuttings in late spring or early summer

Suggested planting locations and garden types

Cottage and informal garden
Flower borders and beds

Pruning

Deadhead flower spikes as they fade

Pests

May be susceptible to slugs and snails

Diseases

Generally disease-free

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