<i>Inula</i>, elecampane: to plant, to grow and to care for

Description and botany

Inula comprises 110 species of plants that are generally perennial, though some are annual or biennial. They originate from Europe, Asia and Africa. Majority of species come from Central Asia, and some occur as far as Himalaya. Having been cultivated for a long time for medicinal properties, Inula helenium has naturalized in several regions worldwide, notably North America and Europe.

In France, nine species occur in wild, including Inula helenium. Inula species can be found in fields, meadows, roadsides, fallow land or uncultivated places… Inula helenium prefers moist, semi-shaded sites (woodland edges, hedgerows, wet meadows…), while other species favour rocky, drier ground.

Inula belongs to large family Asteraceae (nearly 33,000 species), like daisies, oxeye daisies or sunflowers. Main characteristic of this family is presence of flowers gathered in heads. Individual flowers are tiny but gathered in very large numbers to form a sort of disc, a head, resembling a single large flower.

Genus Dittrichia is very close to Inula, since two species formerly classified as Inula have been renamed Dittrichia (Dittrichia graveolens and Dittrichia viscosa).

Inula helenium: Botanical illustration

Name Inula would derive from Greek enaein: to purge, to cleanse, in reference to medicinal properties of plant. Specific epithet helenium refers to Helen, daughter of Zeus in Greek mythology, who was abducted by Paris, sparking Trojan War. Legend says plant grew where her tears fell to ground… Or, according to other accounts, Helen was gathering this plant at moment of her abduction.

Inula helenium is an imposing perennial with woody stump. It is vigorous and robust, quite hardy, and grows rapidly. It has a rather rigid habit, with large downy, villous, relatively thick stems. These stems are ramified at top. However one acaule species exists: Inula rhizocephala, which forms rosettes at ground level, producing flowers in centre of rosette.

Size of Inula therefore varies greatly by species, since they measure between 25 cm and 2.5 m in height. Inula ensifolia is among smallest, while Inula helenium and Inula racemosa are the tallest. Inula helenium can reach 2 m in height… hence common name Great elecampane!

Inula flowers in high summer, generally in July–August (but, depending on variety, flowering can occur between June and October). Inulas then bear, at tops of their erect stems, large golden-yellow heads. They are valued for bright colour. These heads may be solitary or grouped in corymbs.

What looks like a single flower is actually a multitude of tiny flowers, gathered on same plane, just like daisies, oxeye daisies or asters. This particular inflorescence is called a head. It consists of tubular flowers at centre and ligulate flowers at margin, on outside. Ligulate flowers are particularly long and narrow. They give head a more or less “tousled”, untidy appearance. They radiate around centre of flower. They are paler, a brighter yellow, than tubular flowers at head centre. The latter are dark yellow, sometimes slightly brownish. Ligules are female flowers, while tubular flowers are hermaphrodite (bearing stamens and pistil). Around base of head, overlapping bracts can be seen, arranged in several ranks.

Heads of Inula helenium are fairly large, measuring between 5 and 8 cm in diameter, whereas in Inula ensifolia they do not exceed 3 cm. Inula viscosa also has fairly small flowers, rather distributed along stems.

Inula is a good melliferous plant; its flowers attract insects that pollinate them.

Cross-section of a head of Inula ensifolia (photo Stefan Lefnaer): tubular flowers at centre and ligulate flowers at margin are visible / A head of Inula magnifica / Flowering of Inula helenium

Inula helenium forms basal rosette of leaves that are very large, and also bears cauline leaves on stem. These become progressively smaller towards top of stem. Lower leaves are petiolate, while upper ones are sessile, embracing stem. Cauline leaves are alternate, inserted one after another.

In general, Inula leaves are particularly large. Those of Inula helenium can reach 80 cm in length! They are ovate, fairly broad, and simple, not divided. Margin of lamina is dentate. Foliage has rather coarse, massive and imposing aspect, not very fine, with a puckered, somewhat rough texture. Some species have much smaller leaves: in Inula ensifolia they do not exceed 10 cm in length, and are particularly fine, narrow, linear in shape. They have a delicate, graphic appearance.

Leaves are green and marked by white veins. Inula candida has white-grey, downy leaves with very soft appearance. Species Inula viscosa is notable for sticky, viscous foliage.

In Inula helenium, leaves are green above but rather whitish beneath, because covered with hairs, felted. Central vein is prominent on leaf underside.

Inula helenium is a deciduous plant: aerial parts die back in autumn and regrow in spring. Cutting plant back to ground level in autumn is recommended.

Large leaves of Inula helenium, those of Inula magnifica (photo Plenuska), and small linear leaves of Inula ensifolia (photo Krzysztof Ziarnek, Kenraiz)

Inula helenium has been recognised and cultivated since Antiquity for its medicinal root. Root is thick, fleshy and ramified. It is aromatic and can be used to flavour desserts. It has bitter taste and camphor-like odour. It is sometimes used in production of absinthe.

Once Inula flowers are fertilised, they give way to achenes of brown–reddish colour (dry fruit that does not open at ripeness, containing a single seed). These achenes are topped by egrets, which allow them to be carried by wind, just like dandelion seeds!

Inulas tend to self-sow. If you wish to avoid this, remove faded flowers before plant has time to produce seeds!

You can also choose to harvest seeds to attempt sowing and thus propagate plants.

Detail of achenes of Inula ensifolia (photo Stefan Lefnaer) / An infructescence of Inula magnifica (photo Dominicus Johannes Bergsma)

Main Inula varieties

Most popular varieties

Our favourite varieties

Inula helenium

This is elecampane, an imposing and highly decorative perennial that also has the advantage of being medicinal. It has large green leaves and flowers in large golden-yellow heads. Ideal in mixed borders or in a medicinal herb garden.

• Flowering time August, September
• Height at maturity 1,50 m

See the product sheet

Inula magnifica

This is a very handsome species, relatively tall and bearing large, broad leaves. At the top of the stems in summer superb yellow heads unfold. These are formed of tubular flowers in the centre and long, fine ligulate rays on the outside, giving them a rather tousled, untidy appearance.

• Flowering time August to October
• Height at maturity 1,60 m

See the product sheet

 

Inula racemosa Sonnenspeer - Indian elecampane

This variety is impressive in size. It bears tall, upright stems and large, handsome leaves. At the top of its stems many golden-yellow heads open. Place at the back of a border where it will add volume and provide a structural element.

• Flowering time August to October
• Height at maturity 2,50 m

See the product sheet

Inula ensifolia

This is a fairly small species that forms delicate, rather rounded clumps. It bears fine, elongated, very narrow dark green leaves and in summer is covered with numerous yellow heads. It adapts very well to rockeries and borders.

• Flowering time July to September
• Height at maturity 30 cm

See the product sheet

Planting

Where to plant Inula?

You can place Inula in full sun or partial shade. Exposure also depends on your location: if you live in southern France, favour a slightly shaded spot rather than full sun, whereas if you live north of the Loire, you can plant in full sun without problem.

Inula prefers soils rich in organic matter, fertile and deep. It also likes substrates with a calcareous tendency. Soil should be relatively cool but well drained. Avoid heavy, compact soils that retain water. Overall, Inula species are not very demanding and can adapt to different soil types.

Inula helenium fits very well into mixed borders, alongside other perennials that flower in summer. Although container planting is possible, it is preferable to plant Inula in open ground. Some species (the smaller ones, such as Inula ensifolia for example) adapt to rock gardens. Likewise, Inula viscosa particularly thrives in dry, sunny soils and is ideal for rock gardens or dry gardens.

Inula can grow quite tall, so give plants enough space to develop. If possible, choose a sheltered spot out of the wind. Otherwise, taller species may require staking.

Given the height of some species (Inula helenium, Inula racemosa ‘Sonnenspeer’…), we suggest placing them towards the back of borders. Of course, if you mainly grow smaller species such as Inula ensifolia, place them at the front instead.

Some Inula species can be planted in rock gardens. Here, Inula salicina (photo: Leonora Enking)

When to plant?

You can plant Inula in spring (April–May) or in autumn (September–October).

How to plant?

Spacing varies according to species, as they do not all reach the same size, but for Inula helenium we recommend allowing at least 80–90 cm between plants.

1. Start by placing the root ball in a basin of water so it can rehydrate.
2. Choose site for your plant, then dig a planting hole about twice the size of the root ball. Work soil deeply to loosen it and thus make it easier for roots to establish. Feel free to add some well-rotted compost to enrich the soil.
3. Remove plant from its pot.
4. Place it in the planting hole, replace soil around it, and firm gently with the palm of your hand.
5. Water thoroughly.
6. Apply a mulch around the plant to retain moisture and limit weed growth.

You can also watch our video advice on planting perennials:

Care

Inula helenium prefers soils that remain relatively cool. Give occasional waterings during dry spells. We suggest applying mulch, as this will keep soil cool for longer while enriching it with organic matter. Mulching also helps limit weed growth.

Inula helenium is a deciduous plant: its above-ground parts die back for winter. Carry out severe pruning in autumn, cutting the plant back to ground level. It will resume growth in spring.

As it is a fairly tall plant, Inula may need staking to keep stems upright, especially if exposed to wind.

If you wish to avoid self-seeding, remove faded flowers.

As Inula enjoy fertile, organically rich soils, they will appreciate an annual application, in early spring, of some well-rotted compost.

If you wish to harvest Inula roots (for their medicinal and edible properties), do so in autumn, when the plant’s energy moves down into the root system, before the plant enters dormancy for winter. Choose a young plant two or three years old.

Overall, Inula is not very susceptible to diseases and pests. It can, however, be affected by powdery mildew, a fungal disease recognised by a white, felt-like coating on the leaves. If you notice this disease, we recommend removing affected leaves, then spraying a sulphur-based solution or a horsetail decoction.

Propagation

Inula is usually propagated by division, but it can also be sown.

Division of clumps

You can divide clumps of Inula in early spring or in autumn. We recommend doing this on average every three years, as it rejuvenates young plants and restores vigour.

Start by digging up the root system, digging wide enough not to damage it. If necessary, remove excess soil to make it clearly visible. Cut roots into several sections using a sharp knife (they should be at least 5 cm long). Replant them either directly in the ground or in pots to begin with. You can also use this opportunity to recover some roots if you wish to use them for their medicinal properties.

Sowing

Inula produces achenes that can be harvested and then sown in spring or autumn under a cold frame. If growing conditions suit it, it may also self-seed in the garden.

1. Prepare a pot with special sowing compost.
2. Sow seeds by scattering them on the surface.
3. Cover with a thin layer of substrate, then firm lightly.
4. Water with a fine spray.
5. Place the pot under cover in a bright spot but out of direct sun. For seeds to germinate, temperature must be at least 10 °C. Remember to water regularly so substrate remains slightly moist.
6. Prick out as soon as seedlings reach a size that allows handling.
7. You can plant them out in the ground as soon as temperatures become mild enough.

Expect them to flower in the second year.

It is also possible to sow seeds directly in the ground in spring.

Companion planting

Inula are perfect for integrating into mixed borders, especially if you choose large species such as Inula helenium or Inula racemosa, which can be particularly imposing. Place them at back of beds, and pair them with other summer-flowering perennial plants. Choose, for example, achilleas, coreopsis, Anthemis tinctoria, campanulas, echinaceas, hardy geraniums, Penstemon, Phlox paniculata… Not forgetting lightness of Gaura lindheimeri. And, among all these flowers, do not hesitate to include some ornamental grasses, such as Pennisetum, Calamagrostis or Stipa!

Compose a very colourful bed by pairing Inula with other flowers in yellow, orange and red tones…! Enjoy majestic flowering of daylilies, the striking spikes of kniphofias, or the delicate flowers of Salvia microphylla. You can also choose coreopsis, gaillardias, monardas, heleniums, dahlias, Achillea filipendulina… This will produce a superb bed in warm, vivid, blazing hues.

You can pair Inula with other flowers in yellow – orange – red tones! Kniphofia ‘Fiery Fred’, Inula hookeri ‘Mude’ (photo Peganum), Hemerocallis aurantiaca ‘Gladys Perry’, Salvia ‘Rêve Rouge’ and Coreopsis verticillata ‘Moonbeam’

Because they have many benefits, you can use Inula to create a medicinal herb garden. Lay out a physic garden including sages, marigolds, achilleas, mallow, hyssop, chamomile, agastache, common vervain… Also make use of Arnica montana, whose yellow flowers will go very well with those of Inula! You can easily use this garden to harvest plants, dry them and use them for infusions. Also include some culinary herbs: thyme, lemon balm, lavender, mint, dill… which you can use in cooking.

Inula can also fit into a wild, country-style garden. Create a bed with a rather untidy appearance, using tall plants with a free, airy habit. Choose a species such as Inula magnifica, and pair it with achilleas, Verbena hastata, sages, campanulas,Veronicastrum virginicum… Not forgetting ornamental grasses, indispensable for providing a wild meadow feel.

Smaller species can be used in rock gardens. Opt, for example, for Inula ensifolia or Inula candida, and place them with rock geraniums, Delosperma cooperi, Campanula muralis, Dianthus deltoides, sedums and houseleeks… Also enjoy the superb Convolvulus mauritanicus, which offers a delicate soft-blue flowering!

→ Discover more lovely ideas for pairing Inula in our advice sheet!

Did you know?

• A medicinal and edible plant!

Inula helenium has long been cultivated for its medicinal properties. It is the root that is used, mainly as a decoction or infusion. It is effective against cough and to relieve breathing ailments (bronchitis, cough…). It can also be used for digestive problems and to strengthen the immune system. Additionally, it is antiseptic, vermifuge, tonic and diuretic. Roots are rich in inulin (indeed it was Inula that gave its name to this type of sugar).

The root of Inula is also edible, used to flavour desserts. It can be used fresh or dried. It has the advantage of stimulating appetite and promoting digestion. It has a bitter flavour. Young leaves can also be eaten. Roots are harvested in autumn from young plants two or three years old.