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

Description and botany

The Inula comprise 110 species of plants, mostly perennial, but some are annual or biennial. They originate from Europe, Asia and Africa. The majority of species come from Central Asia, and some occur as far as the Himalayas. Cultivated for a long time for medicinal properties, Inula helenium has naturalized in several regions of the world, notably North America and Europe.

In France, nine species occur in the wild, including Inula helenium. Inula can be found in fields, prairies, road verges, fallow land or uncultivated places. Inula helenium prefers fresh soils and partial shade (wood edges, hedgerows, wet meadows…), whereas other species favour rocky, well-drained ground.

Inula belongs to the large family Asteraceae (nearly 33,000 species), like daisies, oxeye daisies and sunflowers. The main characteristic of this family is the presence of flowers gathered in heads. Individual flowers are tiny but grouped in very large numbers to form a kind of disc, a head, which looks like a single large flower.

The genus Dittrichia is very close to Inula, since two species formerly placed in Inula were renamed Dittrichia (Dittrichia graveolens and Dittrichia viscosa).

Inula helenium: botanical illustration

The name Inula probably comes from the Greek enàein: to purge, to purify, alluding to the plant’s medicinal properties. The species name helenium refers to Helen, daughter of Zeus in Greek mythology, who was abducted by Paris, triggering the Trojan War. According to legend, the plant sprang up where her tears fell to the ground… Or, in other versions, Helen was gathering the plant when she was taken.

Inula helenium is a large perennial with a woody stump. It is a vigorous, robust plant, very hardy and fast-growing. It has a rather stiff habit, with large, downy, villous and fairly thick stems. These stems are branched at the top. There is, however, a stemless species: Inula rhizocephala, which forms rosettes at ground level and bears flowers at the centre of the rosette.

Size varies greatly between species: they range from 25 cm to 2.5 m in height. Inula ensifolia is among the smallest, while Inula helenium and Inula racemosa are the tallest. Inula helenium can reach 2 m in height, hence its common name great elecampane.

Inula flowers in midsummer, generally in July–August (though depending on variety flowering can occur between June and October). Inula then bears large yellow-gold heads at the tops of its erect stems. These are valued for their bright colour. Heads may be solitary or grouped in corymbs.

What appears to be a single flower is in fact a multitude of tiny flowers, gathered on the same plane, exactly like daisies, oxeye daisies or asters. This particular inflorescence is called a head. It is composed of tubular flowers in the centre and ligulate flowers at the periphery. Ligulate flowers are particularly long and narrow. They give the head a more or less “ruffled”, untidy appearance. They radiate around the centre of the flower. They are paler, a brighter yellow, than the tubular flowers in the centre, which are dark yellow, sometimes slightly brownish. Ligules are female flowers, while tubular flowers are hermaphrodite (bearing stamens and pistil). Around the base of the head one can see bracts overlapping in several ranks.

Heads of Inula helenium are quite 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, more distributed along the 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 in the centre and ligulate flowers on the outside / Head of Inula magnifica / Flowering of Inula helenium

Inula helenium forms a basal rosette of very large leaves and also bears cauline leaves on the stem. These become progressively smaller toward the top of the stem. Lower leaves are petiolate, while others are sessile, embracing the 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, quite broad and simple, not divided. The lamina edge is dentate. Foliage appears rather coarse, massive and imposing, not very fine, with a puckered and slightly rough texture. Some species have much smaller leaves: in Inula ensifolia they do not exceed 10 cm in length and are particularly fine, narrow and linear in shape. They have a delicate, graphic aspect.

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

In Inula helenium, leaves are green above but rather whitish beneath, being covered with hairs, felted. The midrib is prominent on the underside of the leaves.

Inula helenium is deciduous: aerial parts wither in autumn and regrow in spring. It is advisable to cut the plant back to ground level in autumn.

Large leaves of Inula helenium, leaves 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. The root is thick, fleshy and ramified. It is aromatic and can be used to flavour desserts. It tastes bitter and has a camphor-like odour. It is sometimes used in the production of absinthe.

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

Inula tend to self-seed. If you want to avoid this, remove faded flowers before the plant has had time to produce seeds!

You can also choose to harvest the seeds to attempt sowing and reproduce your plants.

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

Main varieties of Inula

Most popular varieties

Our favourite varieties

Inula helenium

This is Great Mullein, an imposing and very decorative perennial that also has medicinal properties! It has large green leaves and flowers in large golden-yellow heads. Ideal in a mixed border or a medicinal plant 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, with large, broad leaves. At the top of the stems, superb yellow heads unfold in summer. They consist centrally of tubular flowers and, on the outside, long, thin ligules, giving them a rather ruffled, dishevelled 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 for its size. It bears tall, erect stems and large, attractive leaves. At the top of the stems, numerous golden-yellow heads unfold. Place it 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 tufts. It has fine, elongated, very narrow dark-green leaves and is covered in summer 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 plant Inula in full sun or partial shade. Exposure also depends on geographic location: if you live in southern France, prefer 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 soil rich in organic matter, fertile and deep. It also likes calcareous substrates. Soil should be relatively cool but free-draining. Avoid heavy, compact soils that retain water. Overall, Inula are not very demanding and can adapt to different types of soil.

Inula helenium fits very well into mixed borders, alongside other summer-flowering perennials. Although pot cultivation is possible, it is preferable to plant Inula in the ground. Some species (the smaller ones, such as Inula ensifolia) adapt well to planting in a rockery. Likewise, Inula viscosa thrives particularly in dry, sunny sites and will be perfect in a rockery or dry garden.

Elecampane is a fairly large plant; give it enough space to develop. If possible, choose a spot sheltered from wind. Otherwise, taller species may need staking.

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

Some Inula species can be planted in a rockery. 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?

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

1. Start by placing the rootball in a tub filled with water so it can rehydrate.
2. Choose location for your plant, then dig a planting hole about twice the size of the rootball. We recommend working the soil deeply to loosen it and thus ease root installation. Don’t hesitate to add some well-rotted compost to enrich the soil.
3. Remove the plant from its pot.
4. Place it in the planting hole, then backfill around it and gently firm the soil with the palm of your hand.
5. Water thoroughly.
6. Apply mulch around the plant to retain moisture and limit weed growth.

You can also watch our video tips on planting perennials:

Care

L’Inula helenium préfère un sol qui reste relativement frais. Arrosez de temps en temps en cas de sécheresse. We suggest applying mulch, as this will keep soil cool for longer while enriching it with organic matter. Mulch also helps limit weed growth.

L’Inula helenium est une plante caduque : ses parties aériennes disparaissent pour l’hiver. Carry out severe pruning in autumn, cutting the plant back to soil level. It will resume growth in spring.

As a fairly tall plant, Inula may need staking to keep stems upright, especially when exposed to winds.

To avoid self-seeding, remove faded flowers.

As Inula prefer fertile soils rich in organic matter, they will appreciate receiving each year, at the start of spring, a little well-rotted compost.

If you wish to harvest Inula roots (for their medicinal and edible qualities), do so in autumn, as this is when the plant’s energy moves down into the root system, before the plant enters dormancy for winter. Choose a 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 identifiable by a white felt-like coating on the leaves. If you observe this disease, we advise removing affected leaves, then spraying a sulphur-based solution or a horsetail decoction.

Propagation

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

Division of clumps

You can divide Inula clumps in early spring or in autumn. We recommend doing this about every three years, as it helps rejuvenate young plants and restore some vigour.

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

Sowing

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

1. Prepare a pot with sowing compost.
2. Sow the seeds by scattering them on the surface.
3. Cover with a fine layer of substrate, then firm down 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. Water regularly to keep substrate slightly moist.
6. Prick out as soon as seedlings reach a size suitable for handling.
7. You can plant them out in open ground once temperatures become mild enough.

Expect flowering in second year.

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

Companion planting in the garden

Inulas are perfect for integrating into mixed borders, especially if you choose large species such as Inula helenium or Inula racemosa, which are particularly imposing. Place them at back of beds, and pair them with other summer-flowering perennial plants. Choose, for example, achilleas, Coreopsis, Anthemis tinctoria, bellflowers, echinaceas, hardy geraniums, Penstemon, Phlox paniculata… Don’t forget the airy charm of Gaura lindheimeri. And among all these flowers, do include some ornamental grasses, such as Pennisetum, Calamagrostis or Stipa!

Compose a very colourful bed by pairing Inulas with other flowers in yellow, orange and red tones…! Enjoy the majestic flowering of daylilies, the architectural spikes of kniphofias, or the delicate blooms of Salvia microphylla. You can also choose Coreopsis, Gaillardia, Monarda, heleniums, dahlias, Achillea filipendulina… You will obtain a superb bed in warm, vivid, flamboyant tones.

You can pair Inulas 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 offer many benefits, you can use Inulas to create a medicinal plant garden. Lay out an herb garden, incorporating sages, marigolds, achilleas, mallow, hyssop, chamomile, agastache, common verbena… Also include Arnica montana, whose yellow flowers will complement those of Inula beautifully! You can easily use this garden to harvest plants, dry them and use them in infusions. Also add some aromatic plants: thyme, lemon balm, lavender, mint, dill… which you can use in cooking.

Inula can also fit well into a wild, country-style garden. Create a border with a relatively untidy look, using large plants with an open, airy habit. Choose a species such as Inula magnifica, and pair it with achilleas, Verbena hastata, sages, bellflowers, Veronicastrum virginicum… And don’t forget ornamental grasses, essential for creating a wild meadow feel.

Smaller species can be used in rock gardens. Opt, for example, for Inula ensifolia or Inula candida, and plant 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 great pairing ideas for Inulas in our advice sheet!

Did you know?

• Medicinal and edible plant!

Inula helenium has long been cultivated for its medicinal properties. Root is used mainly as a decoction or an infusion. It is effective against cough and relieves breathing ailments (bronchitis, cough, etc.). It can also be used for digestive problems and to strengthen immune system. In addition, it is antiseptic, anthelmintic, tonic and diuretic. Roots are rich in inulin (it is Inula that gave its name to this type of sugar).

Inula root is also edible, used to flavour desserts. It can be used fresh or dried. It stimulates appetite and promotes digestion. It has a bitter flavour. Young leaves can also be eaten. Roots are harvested in autumn from plants aged two or three years.