Turtlehead, <em>Chelone obliqua</em>: planting, cultivation

Description and botany

Turtlehead or Chelone is an herbaceous perennial belonging to family Scrophulariaceae like penstemon, to which it is very closely related. It originates from temperate areas of the United States where it grows naturally on stream banks, in woods and moist meadows or in marshy zones. The genus includes six species of perennials including Chelone glabra, Chelone lyonii, very tall (80 cm) and above all Chelone obliqua, oblique turtlehead with pink flowering, which is the species most commonly found in gardens. This species is considered endangered in its natural habitat. It is available in a few varieties, with white flowers such as Chelone obliqua var. ‘Alba’ or smaller forms such as Chelone obliqua ‘Tiny Tortuga’.

With fairly rapid development, it forms from a powerful, fibrous and taprooting rhizomatous stump a bushy clump with an upright habit rising to about 60–80 cm in height. Oblique turtlehead will reach adult size within two years of cultivation.

Straight stems of fairly rounded section bear a dense deciduous foliage made up of large pairs of triangular to oblong leaves with coarsely dentate margins and marked veins. Their shape strongly resembles that of white nettle. Carried on a very short petiole, leaves measure 5 to 20 cm long and display a fresh to deep glossy green.

This abundant foliage, remaining attractive until autumn, provides a luxuriant green setting for long flowering which begins in August and lasts until first frosts. At stem tips, short, erect, very dense spikes of slightly oblique flowers appear, contrasting with the foliage.

Chelone lyonii (syn. Chelone major) – botanical illustration

Flowers 1–2 cm long are formed of two lips, the upper being in the shape of a blunt galea, resembling, on the botanical side, small foxgloves and, on the animal side, a tortoise’s mouth — hence plant’s nickname “turtlehead”.

These bilabiate corollas set into 5-lobed calyces bear a yellow or white beard and are heightened by a cluster of unequal stamens. These sumptuous small flowers often display hues most frequently purplish-pink or sometimes pure white washed with pale lilac in Chelone obliqua ‘Alba’ or Chelone glabra. They are long-lasting.

These flower clusters turn into small fruits persistent into winter, two-locular capsules containing tiny winged seeds.

Perfectly hardy down to -25 to -30°C, oblique turtlehead can be planted throughout France, except perhaps in regions that are too hot and dry in summer. Undemanding as to exposure, it grows equally well in sun or in part-shade, avoiding scorching situations. It adapts to all fresh to moist soils.

Ideal plant in fresh borders and on banks of a water feature.

Main species and varieties

Most popular

Chelone obliqua

This is the type species! It's a perfectly hardy, striking and easy-to-grow plant. It is therefore perfect for bringing a touch of colour to a sunny or shady corner of the garden, in borders as well as on banks and shores of water features.

• Flowering time September, October
• Height at maturity 60 cm

See the product sheet

Chelone glabra

Little-known, this galane forms a handsome dense clump topped with spikes of cream-white flowers with a slight pink flush. Perfect in a romantic garden, in sun or partial shade in any soil that stays fresh.

• Flowering time September to November
• Height at maturity 60 cm

See the product sheet

Our favourites

Chelone obliqua Alba

This is the most remarkable of the galanes! Hassle-free, its white flowering washed with lilac will bring a refreshing touch to your cool borders and also to banks and shores of water features.

• Flowering time September to November
• Height at maturity 60 cm

See the product sheet

Chelone lyonii Hot Lips

This galane is undoubtedly the largest in the genus! It's a trouble-free plant, perfect for borders in moist soil or for the edges of a pond.

• Flowering time August to October
• Height at maturity 80 cm

See the product sheet

Planting

Where to plant oblique turtlehead or Chelone?

Oblique turtlehead or Chelone is an undemanding perennial that acclimatises to all gardens except the driest, much hardier than Penstemon to wet cold and negative temperatures down to at least -20°C (sometimes -30°C).

It will tolerate non-scorching sun, dappled shade and even deep shade (flowering will be less generous), as it is indifferent to exposure provided soil remains cool, even moist in season.

Although it adapts to all soils except very poor, dry or stony ground, it prefers deep, rich, humus-bearing, loamy soil that retains permanent moisture. Preference is for woodland soil, neutral or slightly acidic. It is particularly at ease in heavy, clay soils and makes an excellent waterside plant. Cool soil allows vigorous growth.

Ideal plant for planting in light understorey or at pond edge, where it will brighten surroundings with its luminous flowering. It provides a gauzy presence in foreground or middle of a border and in edges that are not too dry. Also perfect for bringing colour and light to a dark corner of garden.

When to plant oblique turtlehead or Chelone?

Planting of oblique turtlehead is carried out in spring from February to April or in autumn from September to November, avoiding periods of severe frost and drought.

How to plant oblique turtlehead or Chelone?

In open ground

Prefer planting in small groups of 5 plants per m², spaced at least 30 to 50 cm apart.

• Fork over soil well
• Dig a hole 2 to 3 times wider than rootball
• Amend with leaf mould and well-rotted compost
• Place rootball and backfill with soil
• Firm soil then water copiously until established
• Mulch base to keep soil cool

And find our tips on planting a perennial properly!

Care and maintenance

Hardy and vigorous, Chelone obliqua requires almost no care and will be unfailingly generous provided soil remains cool and sufficiently nourishing.

Must never be short of water, Chelone obliqua is a perennial that quickly withers in drought: mulch the base from June with a good layer of dry straw or turf to retain freshness and water daily during hot spells.

It prefers rich soils: fertilise each spring with well‑rotted compost.

Chelone does not require pruning. Cut back the plant after flowering if you prefer to prevent self‑seeding, otherwise collect the seeds for future sowings and, in spring, cut back old foliage to encourage new leaf shoots.

Every three years in spring when the plant is well established, divide the largest stumps to rejuvenate the plant and preserve abundant flowering.

Chelone obliqua is a robust plant that knows no disease. Its young shoots are only threatened by slugs and snails at the start of growth. In winter the plant disappears completely: mark its position if necessary to make gastropod control easier in spring. Protect it from their appetite with our 7 ways to fight slugs effectively and naturally.

Propagation: sowing, division

To propagate Galane oblique or Chelone obliqua, two options: sowing or dividing clumps in spring.

Dividing clumps of Galane

1. With a fork-spade, lift part of the stump before growth reappears
2. With a spade, cut a good clump with roots
3. Replant immediately in the garden in well-worked soil

By sowing

1. Harvest Chelone seeds at ripeness and sow them in March–April in a seed tray on the surface of good, well-draining seed compost
2. Cover seeds lightly with compost
3. Keep slightly moist, warm (20°C) and in light during germination, which takes about 8 weeks
4. Place under cover
5. Prick out seedlings into individual buckets

Discover our advice and tips to succeed at sowing seeds on our blog !

Companion planting with Galane

Galane, Chelone obliqua or oblique galane is one of those perennials ideal for brightening cool areas in all natural gardens and on banks and shores of water features in marsh gardens. Following summer flowering, it takes over to create natural, colourful scenes in a simple moist border or bed.

It pairs easily with many late-flowering perennials and creates magnificent compositions in early autumn.

An example of a natural pairing: Chelone obliqua, Rudbeckia (‘Goldsturm’, ‘Henry Eilers’ for example), Nepeta subsessilis, Helianthus, Helenium, Eupatorium…

It will quickly become indispensable in a pink or white garden, alongside Japanese anemones, coreopsis and asters that will accompany its flowering through to autumn.

As it appreciates cool conditions, do not hesitate to plant Chelone on the edge of a pond where it will naturally associate with perennials for wet banks, such as Astilbes, water irises, Barbes-de-bouc, rodgersias, Meadowsweet (Filipendula), lysimachias, persicarias, loosestrifes, osmundas, eupatoriums, or an Euphorbia palustris…

In a wild-style garden at the edge or centre of a border, Chelone’s dense spikes will blend easily with cool tones of geraniums, lobelias and rudbeckias. It will also form a very successful partnership with large grasses such as Miscanthus, Panicum and Stipa.

At edge of a romantic border, chic and cool, plant it at the base of shrub roses or alongside the broad foliage of Hostas for a pleasing contrast of shapes and colours.

To keep soil cool at its base, consider groundcover perennials such as sweet woodruff, seaside wormwood, Japanese ferns, heucheras and creeping bugles.