Helichrysum petiolare (Liquorice Plant)

Helichrysum petiolare, commonly called Liquorice Plant or Silver-bush Everlasting Flower. Is a compact, aromatic, evergreen shrub with a spreading form. It has heart-shaped, silvery-grey, felty leaves and creamy-white flowerheads arranged in dense corymbs on long stalks.

It is a drought-tolerant plant native to South Africa. It has become naturalized in many countries, such as the United States, New Zealand and various parts of Europe. It is considered invasive in some places.


Quick Overview

TYPE

Type Shrub

HEIGHT & WIDTH

Helichrysum petiolare height and width

BLOOM TIME

Helichrysum petiolare bloom time

SUNLIGHT

full sun / semi shade

HARDINESS

hardiness (-5ºC / 23º F)

DROUGHT TOLERANCE

drought tolerance aprox 3 months

ORIGIN

Origin South Africa

Taxonomy

  • Botanical name:  Helichrysum petiolare  (hel-ih-KRY-sum pet-ee-oh-LAIR-ee) 
  • Family: Asteraceae (ass-ter-AY-see-eye)
  • Common name:   Liquorice Plant, Licorice Plant or Silver-bush Everlasting Flower
  • Synonyms: Helichrysum petiolatum 
NameMeaning
HelichrysumDerives from Greek words. Heli = Sun, and chrysus= Gold, meaning golden sun. Refers to its round golden yellow flowers.
petiolareLatin meaning long petioles (leaf stalks). Related to the long leaf stalks of this plant.

How to identify Helichrysum petiolare

Helichrysum petiolare shrub (Liquorice plant, Licorice plant, Silver-bush Everlasting Flower)

Shrub

A small, aromatic evergreen shrub with a spreading mound shape that gradually forms a mat, it has numerous stems densely covered in silvery-grey, woolly leaves. Rising above the foliage are long stalks of yellow disc-shaped flower heads surrounded by creamy-white papery bracts arranged in dense corymbs.

The shrub has an average height of 40 to 50 cm (1.3 to 1.6 ft),  and a width of 1 to 1.5 m (3.2 to 4.9 ft).

Its fragrance is similar to liquorice (licorice), hence the common name Liquorice plant. However, it should not be confused with Glycyrrhiza glabra (liquorice), which is the source of the sweet, aromatic flavouring used in candies and sweets.

Helichrysum petiolare stem (Liquorice plant, Licorice plant, Silver-bush Everlasting Flower)

Stem

The stems are loosely branched, straggling or trailing, which may root when in contact with the soil. They are grey and very hairy.

The stem has alternate leaves, which are denser at the base and progressively less dense and smaller towards the inflorescence. The leaves are very loosely arranged on the flowering stems.

Helichrysum petiolare leaf (Liquorice plant, Licorice plant, Silver-bush Everlasting Flower)

Leaf

The leaf is aromatic (liquorice-scented), silvery-green to whitish, densely-haired and with long petioles (stalks).

The shape of the leaf can be orbicular (round), ovate (oval)  or cordate (heart-shaped) with a flat smooth margin.

The size varies between 12 and 35 mm ( 0.47 and 1.37 in) long and 10  to 30 mm  (0.39 and 1.18 in) wide.

Helichrysum petiolare flower (Liquorice plant, Licorice plant, Silver-bush Everlasting Flower)

Flower

The inflorescence is a dense corymb up to 90 mm (3.5 in) with several button-like flower heads enclosed in a bell-shaped or ball-shaped involucre. 

Each flower head has a diameter between 3 and 7 mm (0.11 and 0.27 in) and is composed of tiny yellow flowers

The tiny flowers (disc florets) are tubular and have five petals fused at the base. They are held in a tight bundle enclosed by rows of overlapping papery creamy-white bracts. The flowers are hermaphroditic, with the stamens and pistil sticking out from inside the corolla.


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Helichrysum petiolare Usage

Ornamental

This shrub is very much appreciated for its compact silvery-grey woolly foliage and spreading habit. During the summer, its flower stalks rise above the foliage carrying many small dull creamy-white flower heads with little ornamental value and are often removed by the gardener.

It can be used as a ground cover or intermingled with other plants in rock and gravel gardens. Its cascading growth habit makes it very interesting for containers, hanging baskets and spilling over walls.

Medicinal

Helichrysum petiolare has been used in traditional African medicine. The leaves are used in infusions to treat asthma, coughs and colds. The leaves are also applied to wounds to prevent infection.

Studies have demonstrated its anti-proliferative activity revealing the potential to treat skin cancer and also its anti-diabetic potential.

Biodiversity

The flowers of this shrub are attractive to multiple beneficial insects, such as honey bees, enhancing the biodiversity of your garden. 

Insect Repellent

Burning Heliychrysum leaves releases a fragrance that keeps flies and mosquitos away.

Cultural

The folk healers of South Africa perform rituals burning these plants while dancing and singing in an attempt to create harmony between the living and the dead.

Other uses

The leaves and flowers are used to make soft and aromatic bedding.

Helichrysum petiolare Habitat

This shrub grows in the drier inland parts, sheltered slopes and forest margins at altitudes up to 250 m (820 ft).

They are also seen in eucalyptus plantations and margins of roads.

How to care for Helichrysum petiolare

Cold exposure

This shrub is moderately hardy, tolerating temperatures down to -5ºc (25ºF), for short periods and as long as the soil is well drained. It is not frost-hardy.

Until it is fully established, it will need winter protection.  Add some mulch to protect the roots from low temperatures and the foliage from the wet soil.

Sun exposure

Prefers full sun (at least 6 hours per day)  to maintain its best colour and compact shape. It can also tolerate part shade (around 4 hours of sun a day), but its stems become more floppy, and its foliage won´t be as silvery with less sunlight.

Soil

It likes hot, well-drained soils. It especially dislikes wet soil, which makes it more exposed to fungal diseases.

If prefers moderately fertile soils but can also tolerate poor soils.

It can grow well in acid, neutral and alkaline soils.

Watering

Once established, the Liquorice Plant is drought tolerant and can go for some time without water (about 3 months if the temperature is not too hot). Its silvery leaves reflect the heat, and its hairs prevent water loss.

Overwatering will probably kill it. In particular, the combination of heat and humidity can lead to fungal disease.

During the first two years after planting, you will need to water the young plant every two to three weeks during the summer.  Allow the soil to dry out between watering. In case of a heat wave, water more frequently. Monitor your plants closely and look out for any signs of stress.

To preserve the soil´s moisture, you should add mulch around the root area of the plant (but not too close to the base). Wood chips and gravel are good options for mulching. 

How to prune Helichrysum petiolare

Pruning from time to time is essential to maintain the plant´s compact decorative shape and flowering.

Ideally, you should give it a hard prune in early spring, which is essential to maintain its compactness and avoid becoming too woody or splitting apart. Then a light prune in late summer after flowering to encourage bushiness. 

Be careful to always prune above the leaf, as the stems will not regrow if it is cut back too hard.

How to propagate Helichrysum petiolare

The curry plant can be propagated by seed sown in late winter and early spring.

It can also be propagated by softwood cuttings taken in early spring or by semi-hardwood cuttings taken in later spring and summer.

A good online source for plant propagation techniques can be found at RHS.

If you prefer books, I can recommend the following:

  • Creative propagation: a grower’s guide by Thompson, Peter,
  • RHS Propagating Plants: How to Create New Plants For Free by Alan Toogood, Royal Horticultural Society

Other Helichrysums you may also like

Sources

Sources of information used for this article

Internet

Article from RHS

Article from Missouri Botanical Garden

Models for images from CitySciHub

Vol XVI from FloraIberica

Books

Creative propagation: a grower’s guide by Thompson, Peter

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