Halimium: Planting, Growing and Care

Botany

Halimiums comprise about ten species of shrubs native to the Mediterranean basin (southern Europe, North Africa, Turkey…). They grow naturally in dry areas, on sandy or rocky soils. They are cousins to Rockroses and Sunroses, which they resemble particularly in their flowers and their preference for sun and dry soils. In terms of hardiness, Halimiums can withstand temperatures as low as – 10 / – 12 °C, in well-drained soil. They have a fairly short lifespan: generally, they live between 12 and 15 years in the garden.

Very similar to rockroses, Halimium belongs to the same botanical family, the Cistaceae. Halimiums have even been crossed with rockroses to produce Halimiocistus. These are small bushes with light green, downy foliage that closely resembles that of rockroses, and which bear five-petalled flowers, creamy white or soft yellow, usually marked with purple.

Halimium lasianthum: Botanical illustration

Halimium was named in reference to the saltbush, Atriplex halimus, because the species Halimium atriplicifolium has leaves very similar to those of this shrub.

Halimium is a small bush with a bushy, spreading habit, dense and branched. Generally, it does not exceed one metre in height. Some species such as Halimium commutatum reach only 50 cm in height at maturity.

Halimiums flower in spring or early summer, between April and July, but sometimes as early as March. They then bear cup-shaped flowers, which resemble those of rockroses and measure between 1 and 4 cm in diameter. They are composed of five broad petals, with a velvety texture, as in rockroses and sunroses. They have a cluster of yellow stamens at the centre (male reproductive organs, bearing pollen), which surround the pistil (female reproductive organ, receiving pollen). The ovary is superior, placed above the point of insertion of the petals.

The flowers of Halimium are particularly bright. They can be entirely yellow (Halimium commutatum), yellow marked with purple (Halimium lasianthum subsp. formosum), or white (Halimium ‘April Snow’). The stamens, however, are always yellow and clearly visible. Halimium flowers are appreciated by pollinating insects; their purple markings help guide them towards the centre of the flower. They are very pronounced in the variety ‘Susan’.

The flowers are ephemeral, lasting only a day, but they are renewed over a period of 3 weeks to a month.

The flowers of Halimium calycinum, Halimium ‘April Snow’ (photo Roy lomas) and Halimium ocymoides

Like rockroses, Halimiums have evergreen foliage: they remain decorative all year round, even in winter. Their leaves measure between 2 and 5 cm long, and between 0.5 and 2 cm wide. They are opposite, inserted in pairs on the stems. They take different forms depending on the species. They are either narrow and thick (as in Halimium commutatum), which allows the plant to store water and minerals while minimising exposure to sunlight, or with a broader lamina, spatulate or lanceolate, as in Halimium halimifolium. Similarly, the leaves are either dark green and shiny, or downy and greyish, which allows them to reflect sunlight and protect themselves from drying out.

Halimiums have a deep and branched root system, which enables them to seek water and minerals deep in the soil. This explains why they do not like being transplanted, as it is difficult to dig them up without damaging their roots.

After flowering, Halimium produces brown ovoid capsules, which open by two or three valves to release the seeds they contain. It is possible to harvest the seeds for sowing.

The foliage of Halimium umbellatum, Halimium halimifolium (photo Pancrat), and Halimium lasianthum subsp. alyssoides

The main varieties of Halimium

Most Popular Varieties

Our Favourite Varieties

Halimiocistus

Halimium commutatum

Halimium commutatum is a botanical species that produces entirely yellow flowers in spring, standing out against its dark green foliage composed of small, linear and glossy leaves.

• Flowering time April to June
• Height at maturity 50 cm

See the product sheet

Halimium lasianthum subsp. formosum

This Halimium forms a small shrub with a spreading habit and lanceolate, grey and downy leaves. In spring, it becomes covered with beautiful yellow flowers, contrasted by purple maculate markings on the petals.

• Flowering time May to July
• Height at maturity 60 cm

See the product sheet

 

Halimium umbellatum April Snow

This is a horticultural variety distinguished by its flowers with five white petals surrounding a centre of yellow stamens. It also bears small, linear, dark green leaves.

• Flowering time May to October
• Height at maturity 45 cm

See the product sheet

Halimium April Sun

Halimium ‘April Sun’ produces stunning, entirely yellow flowers in spring that stand out against its dark green foliage! Perfect in a large pot to brighten up a sunny terrace or balcony.

• Flowering time May to October
• Height at maturity 45 cm

See the product sheet

 

Halimiocistus are hybrids between rockroses (Cistus) and Halimiums. They form small bushes with white or yellow flowers, each with five petals.

Halimiocistus sahucii

This Halimiocistus forms a low, rounded bush with a dome-shaped habit, covered in spring with a multitude of pure white-petalled flowers surrounding a bright yellow stamen centre. Exceptionally luminous!

• Flowering time August, September
• Height at maturity 50 cm

See the product sheet

Halimiocistus wintonensis Merrist Wood Cream

This small bush has rockrose-like leaves (ovate, grey-green and downy) and bears spring flowers with creamy-white petals, contrasted by broad purple maculate markings surrounding the vivid yellow centre.

• Flowering time June, July
• Height at maturity 60 cm

See the product sheet

Planting

Where to plant Halimium?

Halimium is a plant that loves warmth: place it in a sunny spot, for example against a south-facing wall. If possible, choose a location sheltered from cold winds. It also requires well-drained soil that doesn’t retain moisture. It thrives in poor, stony or sandy soils. Don’t hesitate to improve drainage by mixing coarse sand or gravel into the soil, or by planting it on a raised mound or in a rockery to facilitate water runoff. In terms of pH, Halimium prefers slightly acidic to neutral soils.

Halimium is an ideal plant for dry gardens, sunny slopes and rockeries. You can pair it with other Mediterranean plants that enjoy similar growing conditions: lavender, thyme, rosemary, cistus, santolina, olive trees, oleander… It can also be grown in a large pot placed on a terrace or balcony.

Choose its location carefully. Once planted, it dislikes being moved, as this could damage its deep roots.

When to plant?

If you live in a warm, dry climate like the Mediterranean basin, we recommend planting Halimium in autumn. In cooler regions, opt for spring planting, around April, so it can establish itself in milder temperatures.

How to plant?

In the ground:

1. Once you’ve chosen the location, dig a planting hole two to three times the size of the root ball.
2. Add coarse sand or gravel to improve drainage, mixing it into the planting soil.
3. Remove the Halimium from its pot and place it in the centre of the hole.
4. Backfill with soil around the plant and lightly firm it down.
5. Water thoroughly.

Continue watering in the weeks following planting.

In a pot:

1. Choose a large pot, preferably terracotta or plastic, with a minimum diameter and depth of 30 cm (or larger depending on the plant’s age and size).
2. Add a drainage layer of clay pebbles or gravel at the bottom.
3. Fill with a well-draining mix, such as equal parts compost, garden soil and coarse sand.
4. Plant the Halimium in the centre of the pot.
5. Backfill with substrate around the plant.
6. Lightly firm the soil.
7. Water well.

Halimium halimifolium

Maintenance

Halimium is a drought-resistant bush: it generally won’t need watering, except during the first year after planting (while it establishes itself and develops its root system) and during prolonged dry spells. However, if grown in a container, it will appreciate occasional watering. Remember to let the growing medium dry out between waterings, and never leave standing water in the saucer.

In cooler climates where winter temperatures may drop to -10°C, protect your Halimium by applying a thick layer of mulch around its base and covering it with horticultural fleece during severe frosts.

Halimium thrives in poor soil, so it doesn’t require fertiliser. If grown in a container, you can top-dress annually by replacing the top few centimetres of growing medium with fresh compost.

You can prune Halimium after flowering to encourage a dense habit, but avoid hard pruning.

If you’re growing Halimium in a container in an area prone to frost, move it to sheltered protection for winter.

Being tough and resilient, Halimiums show good resistance to diseases and parasitic problems.

Propagation

Sowing

Halimium can be propagated by sowing in spring or autumn.

1. Prepare pots by filling them with special sowing compost.
2. Firm down and level the surface.
3. Place the seeds on top.
4. Cover with a thin layer of compost.
5. Water gently using a fine spray.
6. Place the pots under shelter, in a bright spot out of direct sunlight.

Propagation by cuttings

Halimium can be propagated by cuttings in early autumn, around September, using semi-hardwood cuttings.

1. Take a semi-hardwood stem, around 10 cm long.
2. Remove the leaves from the lower half, keeping only a few at the top of the stem. Similarly, if the stem has flowers or fruits, remove them.
3. Prepare a pot by filling it with a mix of compost and coarse sand. Firm lightly and water.
4. Insert the base of the stem into the substrate, then firm around it to avoid air pockets.
5. Place the cutting in a humid environment by covering it with a cut plastic bottle or a clear plastic bag. This helps maintain a humidity-saturated atmosphere.
6. You can then place the cutting under a cold frame, out of direct sunlight.

Ensure the substrate remains slightly moist by watering if needed, and remember to ventilate regularly by removing the bottle or plastic bag to prevent the cutting from rotting.

Association

Halimium, native to the Mediterranean region where it thrives in sandy or rocky soil, is perfectly suited for a Mediterranean-style garden, evoking sunshine and holidays! Plant it alongside the striking silhouette of an olive tree, accompanied by fig trees, strawberry trees, rockroses, palms such as the Chamaerops humilis, yuccas and agaves for their exotic flair. Discover the stunning bush Anthyllis barba-jovis, with silvery foliage and pale yellow spring flowering. Consider aromatic plants like lavender, thyme, rosemary, savory, and helichrysum…

Explore our selection of perennials for a Mediterranean garden

Chamaerops humilis, Halimium lasianthum, Euphorbia myrsinites (photo Renee Grayson), Lavandula stoechas, Cistus monspeliensis (photo Javier Sanchez Portero) and Agave americana ‘Variegata’

You can also plant Halimium in a large pot on a sunny terrace, alongside palms, prickly pears, yuccas, and agapanthus. This creates a delightful exotic setting right by your home!

Similarly, don’t hesitate to incorporate Halimium into a rockery or scree garden, alongside other drought-tolerant plants like sedums and houseleeks, Phlox subulata, aubrietas, sunroses, eryngiums, and spurges. You can also add ornamental grasses, such as blue fescues or stipas.

Check out our guide “15 Plants for a Sunny Rockery”