Description & Interesting Facts:

Calocephalus brownii, also known as the Silver Bush or Cushion Bush, is an unusual shrubby evergreen perennial that belongs to the Asteraceae family. It is native to warm and sunny Australia, and for that reason it is ideal for our sunny South African gardens.

In its natural habitat it favours growing in temperate coastal forests in areas of Mediterranean climate, which are found on Australia's southern and southwestern coast. These regions have moderate temperatures and rainy weather during the winter, with hot and dry summers, except on the immediate coast, where a cool sea breeze helps buffer high temperatures.

It is easily identifiable with its intriguing silver-grey foliage and thin and wiry stems which are silvery white and downy, growing outwards quite chaotically, holding the soft scale-like leaves so closely to the stems that the bush appears leafless. In late spring and summer small button-like, pale-yellow flower heads adorn the plants, adding to their allure.

The bush is generally rounded in shape, resembling a shimmering silver ball, and typically grows anything from 30 to 60cm tall, but is known to reach 70cm to 1m in height with an equal spread.

In the Garden:

Did you know that silver-foliaged plants are often selected for garden landscapes simply because of their functionality? Due to their hairy or waxy leaf surfaces silver-foliaged plants like the silver bush have the ability to reflect sunlight and prevent water loss, making the plants both heat and drought tolerant, and a great choice for dry gardens or xeriscaping.

The silver bush is renowned for its ability to withstand strong winds and poor soils in coastal gardens, but is just as effective in inland gardens for the same purposes. It’s a low-maintenance plant that's easy to grow and can thrive in a variety of garden settings.

 The silver bush is not just used for its hardiness but also for its good looks, and there are many reasons why you should add silver-grey foliage to your landscape. We all know how silver-foliaged plants create that magical, mystical atmosphere by the light of the full moon, so if you spend a lot of time outdoors in the evening, plant a ‘moonlight’ garden using plants that don’t disappear in the dark, but rather come to the forefront.

Silver-grey is a wonderful contrast for more vibrant colours and the silver bush will add a lot of texture. It is also a valuable ornamental accent plant, and its mounded habit makes it an ideal filler plant in beds and borders, and perfect for pots on a sunny patio or balcony. 

Its cushion-like appearance and fine, wiry stems give it an airy, almost ethereal look, making the silver bush a perfect choice for modern and minimalist garden designs.

Although the bush is usually rounded in shape and grows quite tall, it is often used as a ground cover in large areas because it can create cover in a short period.

Cultivation:

Where does the silver bush grow best?

This perennial thrives in a Mediterranean type climate, making it ideal for our winter rainfall regions and perfect for coastal gardens as it is extremely tolerant of salt spray, wind, poor sandy soil and drought.

How fast does the silver bush grow?

The silver bush has a moderate growth rate, and will take several years to reach its full height and spread.

Is the silver bush frost hardy?

In mild climates the silver bush is a hardy evergreen perennial. It is also reasonably frost-hardy, but in cold conditions it will benefit from protection. In severely cold and frosty winter regions it is often treated as a summer annual.

Does the silver bush grow in subtropical climates?

This plant thrives in subtropical climates but may suffer from fungal infections if humidity is very high. In these regions plant in full sun and ensure that there is adequate spacing between the plants to facilitate good air flow around the foliage.

What soil type is best for the silver bush?

The silver bush is known to thrive in poor, sandy soil which has perfect drainage, but is not picky about soil type and will adapt to most well drained garden soils, even clay and rocky soils.

Does the silver bush require full sun?

This plant prefers sunny or partially shaded locations in the garden. Adequate exposure to sunlight will promote compact, healthy growth.

How much water does the silver bush require?

Although the silver bush in known to be drought resistant once established, regular watering is recommended during its first year of growth to encourage a healthy root system.

Under severe drought situations it will go semi or totally dormant, so to keep it looking at its best in the garden, water moderately during long hot and dry summer spells.

In cold winter regions reduce the amount of water given during the winter months.

Avoid waterlogging, as this can lead to root rot.

Does the silver bush need feeding?

The silver bush does not need supplemental fertilisers and will thrive in nutrient poor soil. However, if you are growing it in a pot you can feed occasionally with a liquid fertiliser.

Does the silver bush need pruning?

Pruning is generally not necessary, but the plant responds well to light pruning to maintain its compact form and promote dense growth. Pruning can be done in early spring before the active growing season.

Propagation:

The silver bush grows easily from seed and is also propagated via 5 to 10cm semi-ripe cuttings, rooted in a well-drained mix under mist for humidity. Using a rooting hormone and providing warmth with indirect sunlight helps develop a strong root system.

Problems, Pests & Diseases:

If grown correctly the silver bush does not suffer  from any serious problems and is generally resistant to pests and diseases, contributing to its low-maintenance nature.

If overwatered root rot can set in, and the plant is also susceptible to grey moulds if humidity is high.

Toxicity

The silver bush poses a mild toxicity risk to cats and dogs. Ingestion of any part of the plant can cause symptoms like vomiting, diarrhoea, and lethargy. Prompt veterinary care is crucial if signs of poisoning appear.

Discourage pets from chewing on plants, and young children should always be supervised in the garden.