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Choosing a calluna

There are hundreds of calluna cultivars, so there is lots of variety in flower and foliage colours. To make it easier for you to choose, begin by going for the plants offering the colours you prefer, as they are otherwise similarly easy to grow.

When choosing calluna it also helps to bear in mind the following:

• Calluna need a sunny open position
• Grow in acid soil
  

  The acidity/alkalinity of soil is measured on a pH scale, which runs from 0 to 14. Neutral soil has a pH of 7. Acid (or ericaceous) soil has a pH of less than 7, and the lower the pH, the more acidic the soil. You can measure your soil pH using a simple testing kit. Acid-loving (ericaceous) plants include rhododendrons, camellias, heathers and blueberries. Adding lime to soil will reduce its acidity. A slightly acidic soil of pH 6.5 is the best general-purpose pH for gardens, allowing a wide range of plants to grow.

  ( pH
  

  This describes how acid or alkaline soil is, and is expressed as a number between 0 and 14. Soil with a pH of 7 is neutral, an acid soil has a lower value, and an alkaline soil has a higher one. Most plants grow best in soil that’s within a specific pH range, so it’s useful to know your soil’s pH. Testing kits are easy to use and widely available in garden centres and online.

  5.5) to neutral (soil) as plants will fail to thrive at higher (alkaline) pHs. There are a couple of ways to check the pH of your soil. The simplest is to look at the plants in your garden/neighbours' gardens. If rhododendrons, camellias and blue-flowered hydrangea are growing there, the soil is likely to be acidic. If you don't have these plants or are unsure, use a pH test kit. If it turns out that you have alkaline soil
  

  The acidity/alkalinity of soil is measured on a pH scale, which runs from 0 to 14. Neutral soil has a pH of 7. Alkaline (lime-rich) soil has a pH above 7, and the higher the pH, the more alkaline the soil. Chalky or limestone soils are alkaline. You can measure your soil pH using a simple testing kit. If you have alkaline soil, choose plants that will thrive in it – acid-loving or ericaceous plants such as rhododendrons will not. Club root disease (which affects brassicas) is less prevalent in alkaline soil.

  unsuitable for calluna, you could still grow calluna in containers using peat-free ericaceous
  

  Plants that thrive in acid or ericaceous soil, which has a pH of less than 7 (neutral). You can measure your soil pH using a simple testing kit. Ericaceous or acid-loving plants include rhododendrons, camellias, heathers and blueberries.

  (acidic) potting compost
  

  Can refer to either home-made garden compost or seed/potting compost:

  
  • Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own.

• Plant in groups of three or five for an impressive show of colour and to create effective ground cover. Calluna are usually low growing and range in height from about 20cm (8in) to 60cm (2ft) tall. They can spread to about 75cm (30in) wide
• As well a traditional calluna cultivars, you will now see for sale the Calluna Bud
  

  A bud is a small, undeveloped shoot that contains the potential for new growth. Buds are typically found on stems, where they can be apical (found at the tip) or axillary (found between leaf axils) and may develop into leaves, shoots or flowers.

  Bloomers series. This has an upright growth habit and the plants are usually compact with a long flowering period. They are good in window boxes or patio containers
• Calluna are very attractive to bees and great in wildlife gardens, but those with double flowers or the popular Bud Bloomers series which produce masses of colourful closed buds only, do not have any value as a pollen or nectar
  

  Sweet liquid mainly produced by flowers to attract pollinators. Honeybees make honey from nectar.

  source

Whatever your preferences, consider going for calluna that have received the RHS Award of Garden Merit as these have been tested and perform well in average garden conditions.

Buying calluna

You can expect to buy calluna in 9cm (3½in) or 1-2 litre pots at most times of the year from garden centres and nurseries. The smaller plants just take a year extra to reach the size of those sold in bigger pots, but they are quite a bit cheaper so a great option for those on a tighter budget.

Use our Find a Plant tool for stockists nearby.

When to plant

Ideally plant in spring, as the warm, moist conditions will help the plants roots establish in the soil. If you buy calluna in summer and autumn, you can still plant, just make sure they are well watered in dry spells as the soil needs to stay moist but not soggy.

Where to plant

Calluna are easy to grow in the garden if the conditions are right. The soil needs to be acidic (see Choosing a Calluna above) and a sunny well-drained soil for planting, as calluna can rot off if conditions are too wet.

How to plant

In the ground:

• Dig in organic matter, such as well-rotted leaf mould, composted pine needles or composted bracken (which are suitable for ericaceous
  

  Plants that thrive in acid or ericaceous soil, which has a pH of less than 7 (neutral). You can measure your soil pH using a simple testing kit. Ericaceous or acid-loving plants include rhododendrons, camellias, heathers and blueberries.

  plants), to the soil excavated from the planting hole and before backfilling and firming the soil around the roots
• Plant so that the top of rootball
  

  The roots and accompanying soil when a plant is removed from a container or lifted from the ground.

  is level with the surrounding soil
• Firm in the rootball with your hands to remove any air pockets. The top of the rootball should be just below the soil when finished.
• Water well after planting, aiming for the soil to be moist but not soggy

See our step-by-step guide to planting a shrub to help you plant your heather.

RHS guide to planting a shrub

In containers:

• They grow well in window boxes, patio pots and hanging baskets
• When planting calluna in any container, make sure the pot has good drainage holes
• Use a peat-free ericaceous compost
  

  Can refer to either home-made garden compost or seed/potting compost:

  
  • Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own.

  . This is acidic, so ideal for these plants (they'll fail to thrive in normal multi-purpose compost)
• Add some slow-release ericaceous fertiliser to the compost to provide feed for the first summer
• Repot every three years or so to ensure good growth
• They will eventually need a pot approximately 45cm (18in) wide, depending on the spread of the plants

Growing plants in containers

Watering

Water plants in the first 18 months after planting until established, aiming to keep the soil moist but not soggy. They should be fine after that as Calluna are usually drought tolerant.

Feeding

On a fertile soil, no feeding is required. An annual mulch

Mulch is a layer of material, at least 5cm (2in) thick, applied to the soil surface in late autumn to late winter (Nov-Feb). It is used to provide frost protection, improve plant growth by adding nutrients or increasing organic matter content, reducing water loss from the soil, for decorative purposes and suppressing weeds. Examples include well-rotted garden compost and manure, chipped bark, gravel, grit and slate chippings.

of organic matter such as well-rotted leaf mould or composted pine needles will suffice.

For container grown plants, add some slow-release ericaceous

Plants that thrive in acid or ericaceous soil, which has a pH of less than 7 (neutral). You can measure your soil pH using a simple testing kit. Ericaceous or acid-loving plants include rhododendrons, camellias, heathers and blueberries.

fertiliser annually in March/April to keep them flowering well or use a liquid feed such as Phostrogen between April and September according to the instructions.

Deadheading

You can deadhead after flowering to remove the brown flower heads and improve the plant's appearance. The simplest way to do this is with a pair of shears, snipping off the flower stalks just above the foliage.

Overwintering

No special treatment is required in winter unless you are growing these plants in containers – just make sure pots have good drainage and they do not sit in water over winter.

Prune calluna after flowering.

• Trim off the flowering stems when the flowers have faded to brown
• Calluna do not regenerate well from old wood, so do not cut back too hard
• Calluna are not long-lived plant, and are best replaced every 10 years or so, when they look straggly and tired

Calluna can be propagated by layering or taking cuttings

A method of growing new plants from parts of an existing plant, such as sections of root, stem, leaf or bud. When prepared correctly and planted in the right conditions, they can produce roots and eventually become independent plants. There is a wide range of different methods for taking cuttings, depending on the plant and time of year.

. If you just want one or two new plants, then try layering:

• Layering is an easy method if you don't have space to take cuttings.
• Select a few stems from the outer edge of the plant
• Make a shallow trench with a trowel, and lay in the stem
• Pin the stem down with hoop of wire
• Cover the stem with soil, leaving the tip showing
• Mound soil around the tip so it is upright
• After a few months, the buried stem will have rooted
• This can then be cut away from the main plant, and transplanted
  

  Moving a plant from one growing position to another, often from a pot to its final spot in the garden.

  elsewhere in the garden

You can also propagate by semi-ripe cuttings

Semi ripe cuttings are taken from summer to mid-autumn (Jul-Sep) from healthy stems grown this season. The base of the cutting is firm, while the tip is still soft. Use for climbers, herbs, evergreen shrubs, conifers and hedging plants.

• Take semi-ripe cuttings in late summer, using non-flowering material approximately 5cm (2in) long
• Plant in pots of free-draining, peat-free cuttings compost
  

  Can refer to either home-made garden compost or seed/potting compost:

  
  • Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own.

• Place in a propagator
  

  A propagator is a portable, lightweight structure usually plastic, with a vented or unvented lid to provide a humid, slightly warmer atmosphere. It is useful to help seeds germinate and root cuttings. It may have adjustable, thermostatic temperature control.

  out of direct sunlight until rooted. Keep just moist as damper conditions will cause them to rot

Calluna are generally trouble free, but may suffer from fungal diseases such as phytophthora root rot, especially in wet soils.

Rabbits and deer will graze on these plants if they can get into your garden.