How to grow hollies

What are hollies?

Hollies are very versatile shrubs, or slow-growing small trees, for sun or partial shade and most are hardy throughout the UK. Best known for their spiny evergreen leaves and red berries, hollies – in the genus Ilex – are surprisingly varied. Foliage may be smooth and spine-free or spiky all over, in shades of dark, bright or blueish green plus a wide range of variegated

Variegated means having leaves or other plant parts with streaks, blotches or patches of different colours. Typically, these would be a combination of two colours, such as green and gold or green and white.

forms. Berries on female plants may be red, orange, yellow or black, and there are deciduous

Deciduous refers to plants (mainly trees and shrubs) that lose their leaves seasonally, usually during autumn. This is a natural process triggered by the season's shorter days and lower temperatures and allows plants to conserve energy during the winter months.

species that display their berries on bare winter stems. 

Choosing

The main features affecting your choice are likely to be overall size and shape, foliage interest and berry display. Look for hollies that have received the RHS Recommended: Award of Garden Merit which shows they performed well in RHS trials so are reliable choices.

Size and shape

Hollies range in size from small shrubs reaching less than a metre to small trees ultimately reaching 8-15m. However, they are generally slow-growing and respond well to pruning and training, so their height and spread can be easily controlled.

Ilex crenata used to be recommended as an ideal alternative to box. From our experience and members’ enquiries, this plant dislikes hot, dry summers and cold, wet winters. It thrives best in cool summer temperatures and well-drained, slightly acidic soil that has summer moisture. This may make it an unsuitable choice for many gardens in the UK.

Naturally compact varieties are a good choice for clipped topiary shapes, and there’s a good choice of cultivars for medium to tall hedges.

In time, hollies can make impressive specimen shrubs or small trees, with year-round interest.

Foliage

Most hollies, including UK native

A native plant is one that originated or arrived naturally in a particular place without human involvement. In the British Isles, native plants are those that were here during the last ice age or have arrived unaided since.

common holly (Ilex aquifolium), have spiny leaves making them a good choice for impenetrable, medium to large hedges. The hedgehog holly (I. aquifolium ‘Ferox’) is truly ferocious, with spines all over the leaf surface, while I. × altaclerensis ‘Camelliifolia’ is spine-free.

There is a wide choice of variegated cultivars which are popular for clipped topiary, such as lollipop-shaped standards, cones and obelisks.

More unusual hollies have leaves with different shapes, or with a distinctly blue-grey or olive-green cast. Some of these are less hardy than more popular species, so may need a more sheltered position. A few species are deciduous, shedding their leaves altogether in autumn. These need 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.

and a sunny spot to thrive.

Berries

Hollies produce inconspicuous, usually white or cream, cup-shaped flowers in spring clustered at the base of the leaves where they attract pollinating insects.

Most hollies are either male or female. For the berries to set, female plants need a male plant growing nearby to act as a pollinating partner

For successful flower pollination, most fruit trees need one or two pollination partners – other similar trees of different cultivars growing nearby that flower at the same time. Two trees of the same cultivar cannot fertilise each other. There are a few varieties that are self-fertile, such as ‘Victoria’ plums, which can produce fruit without a pollination partner, but even these tend to crop better with another compatible variety nearby.

, although some such as Ilex aquifolium ‘J.C. van Tol’ are self-fertile and will produce berries alone. One male plant can pollinate many female plants within 20-50m. Always check the label as cultivar

Gardeners often use the word variety when referring to a specific plant, but the correct botanical term is 'cultivar'. Whichever word you use, it means a distinctive plant or plants, given a specific cultivar name and usually bred to enhance certain characteristics, such as flower or fruit size, colour, flavour or fragrance, plant size, hardiness, disease resistance, etc. Additionally, it is worth knowing that, botanically, variety has another meaning - it refers to a naturally-occurring distinct plant that only has slight differences in its looks. For example, Malva alcea var. fastigiata differs from typical plants by having an upright habit.

names can be misleading: I. × altaclerensis 'Golden King' is a female and I. aquifolium 'Silver Queen' is a male.

Deciduous hollies such as Ilex verticillata and I. serrata prefer neutral to acid soils and a sunny position. They are not frequently grown in UK gardens, but I. verticillata is widely available at Christmas time as cut branches covered in red berries. In the garden you need both a male and female deciduous holly for berries – they cannot be pollinated

When a flower has received pollen, so is able to make seeds.

by evergreen species.

Most hollies produce red berries, but I. crenata and I. glabra have black berries, I. aquifolium ‘Bacciflava’, I. aquifolium ‘Pyramidalis Fructo Luteo’ and I. verticillata ‘Winter Gold’ have yellow berries, and I. aquifolium ‘Amber’  has orange berries.

More inspiration

Visit National Collection holders if you would like to see a wider range of hollies, including RHS Garden Rosemoor in Devon.

Use the RHS Find a Plant tool to browse descriptions and images of many different hollies, with filters to narrow down your search by a range of characteristics including size, leaf and berry colour.

Buying

Hollies are available for sale as container-grown plants all year round. During autumn to spring, hedging is also available as bare-root

These have been lifted from the ground while dormant, with little or no soil around their roots. Various plants may be available bare root, including fruit trees, hedging plants and some perennials. They are generally cheaper than plants in containers, but are only available in winter/early spring, while dormant

plants, and specimen trees and shrubs as rootballed plants (where the root system and surrounding ball of soil is being held together with fabric and, sometimes, wire mesh).

Buying: garden centre plants

Buying: mail order plants

Buying: trees and shrubs

How to choose healthy plants

When to plant

• Hollies bought in containers can be planted at any time of year.
• Autumn and spring are the best times to plant as the moist but warm soil encourages good root growth.
• If you buy a holly in summer, plant it as soon as possible and water it regularly. 
• You can plant in winter as long as the soil is not waterlogged
  

  Describes soil or potting compost that is saturated with water. The water displaces air from the spaces between soil particles and plant roots can literally drown, unless they are adapted to growing in waterlogged conditions. Waterlogging is common on poorly drained soil or when heavy soil is compacted.

  or frozen.
• Bare-root
  

  These have been lifted from the ground while dormant, with little or no soil around their roots. Various plants may be available bare root, including fruit trees, hedging plants and some perennials. They are generally cheaper than plants in containers, but are only available in winter/early spring, while dormant

  and rootballed hollies should be planted when dormant from autumn to early spring – these are the times they will be supplied by nurseries.

Where to plant

• Choose a position in full sun or partial shade; plain green hollies will tolerate full shade.
• Variegated
  

  Variegated means having leaves or other plant parts with streaks, blotches or patches of different colours. Typically, these would be a combination of two colours, such as green and gold or green and white.

  cultivars are best planted in a sunny situation to encourage good leaf colour.
• Avoid planting in areas that are prone to waterlogging or become very dry in summer.
• Most cope well with a wide 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.

  range, but some, including Ilex verticillata, I. serrata, I. opaca and I. pedunculosa, need neutral to 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.

  .
• Clipped shapes and standards (lollipops) are popular choices for containers.

How to plant

Our guide below takes you step-by-step through planting your holly.

Trees and shrubs: planting

If your soil is prone to staying wet, consider planting on a slight mound, about 25-30cm high and 1m in diameter. This will help prevent roots from rotting in wet soil. 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.

the mound well with a 5-7cm layer of well-rotted organic matter, such as garden 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.

.

If planting a rootballed holly, follow the planting and aftercare guide below.

Trees: buying and planting specimens

For holly hedges, follow this planting guide.

Hedges: planting

Planting hollies in containers

Plant your holly in a container about 5cm larger all round than its original pot. Fill the gap with a peat-free compost with added John Innes or a 50:50 mix of John Innes No 3 and peat-free multi-purpose compost.

After two to three years, the roots will have filled the container and it will benefit from re-potting in spring into a larger container – again about 5cm larger all round.

Growing plants in containers

How to repot a plant

Watering

Water newly planted hollies during dry spells in spring and summer for the first couple of years, until their roots have grown out into the surrounding soil. Bear in mind that if you are planting a more mature specimen they can take longer to fully establish.

Established hollies are fairly drought-tolerant and shouldn’t need regular watering. However, if they are growing on

Transferring young plants from one container to a slightly larger one, where they will have more room to grow and fresh potting compost. This encourages continuous, healthy growth.

very dry soils, or in a very sunny spot, they may need watering in prolonged dry spells. Hollies and other evergreens are quite slow to show signs of stress. If leaves start to lose their lustre and look matt it’s time to act.

Watering

Feeding and mulching

Hollies planted in borders do not need any special feeding unless they are showing signs of nutrient deficiencies. However, they will benefit from regular mulching in spring with a layer of bulky organic matter, such as homemade 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.

or manure-based soil conditioner. This will hold on to moisture in the soil, reducing the need to water, and provide nutrients

To grow well, plants need a wide range of nutrients in various amounts, depending on the individual plant and its stage of growth. The three key nutrients usually taken up from the soil are nitrogen, phosphorus and potassium. Plants also need carbon, oxygen and hydrogen to make carbohydrates — their main energy source. Carbon and oxygen come from the air as carbon dioxide, while hydrogen is drawn from water absorbed by the roots. Other important soil nutrients include magnesium, calcium and sulphur. Most garden soils contain enough of these nutrients to support healthy plant growth.

as it breaks down. Leave a 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.

-free circle immediately around the base of the plant to prevent stem rot.

Nutrient deficiencies

How to feed plants

Mulches and mulching

Hollies in containers

The small volume of compost in a container can rapidly run short of water and nutrients, so will need regular top-ups. 

Container maintenance

Evergreen specimen trees and shrubs

Prune in mid- to late summer.

• If growing as a specimen tree or shrub, prune to encourage the plant to develop a strong central leader. You’re looking for one main central shoot – if there are other vertical shoots that are competing for that central, top spot, use secateurs to cut out or shorten the competing shoots.
• On more exposed sites, you may need to stake the central stem to keep the plant straight.
• To enhance the natural pyramidal shape, prune any protruding branches that spoil this shape, cutting back to within the canopy to hide the cut ends.
• If you are growing variegated
  

  Variegated means having leaves or other plant parts with streaks, blotches or patches of different colours. Typically, these would be a combination of two colours, such as green and gold or green and white.

  cultivars, watch out for reverted (plain green) branches and remove them, pruning back to branches that are showing variegation
  

  Variegated means having leaves or other plant parts with streaks, blotches or patches of different colours. Typically, these would be a combination of two colours, such as green and gold or green and white.

  .
• Trim off winter-damaged young growth in mid-spring.

Evergreen hedges and clipped shapes

Prune in late summer. If pruned earlier a second flush of uneven regrowth may occur, and spoil the clean outlines created by pruning. 

See our guide to training and pruning hedges.

Hedges

Pruning hedges

Deciduous shrubs

Keep pruning to a minimum, lightly trimming in winter.

If training as a bonsai, follow our guide below.

Bonsai

Renovating older plants

• Evergreen hollies generally respond well to renovation pruning in spring. You can safely reduce growth by up to a third in one year.
• If you need to do more substantial reduction, spread the pruning over two to three years.
• The regrowth can be vigorous but is often not evenly spread across the plant. To help it form a new, neat surface, cut off the tips from the new shoots when they are about 7-15cm long. If you do get clumps of new growth, you can thin them by snapping out a few of the shoots by hand when they are still young.
• If renovating a hedge, follow the advice below.

Hedge Renovation: Tips for Restoring Overgrown Hedges

Layering

This is the easiest and most successful way to propagate hollies. In spring, take a young shoot growing close to the ground and bend it down to the soil. Where it touches the ground, dig a shallow hole and peg the branch into the bottom with a hoop of wire. Fill in the hole with soil.

The layer can take a couple of years to root but can then be cut off the main plant, dug up and moved to its final position in autumn or spring.

Layering

Cuttings

Propagating from 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.

is quite difficult, but can potentially produce a lot of new plants that are identical to the parent. The best methods to try are:

Hardwood cuttings

Hardwood cuttings are taken from mid-autumn until late winter from vigorous healthy shoots of the current year's growth - this will be woody but pliable. Use for deciduous climbers, shrubs, trees (including fruit) and some evergreens such as hollies.

in autumn to mid-winter:

• Prepare stems 7.5-10cm long by removing all but the top two leaves
• To improve the chances of rooting, ‘wound’ the cutting by slicing off 2cm of bark
  

  Bark is the outermost layer of woody plants (trees, shrubs and woody climbers). It is several cells thick and provides protection against physical damage, disease and environmental stresses. Bark comes in a wide variety of colours and patterns, and these can help gardeners when identifying plants. The fissures and crevices of bark on older plants also creates valuable habitat for many garden creatures as well as lichens and small plants.

  from the base up the side of the cutting
• Push the cuttings into pots containing a 50:50 mix of peat-free multi-purpose 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.

  and horticultural grit
• Water well and, ideally, place in a heated propagator
  

  A heated propagator is a portable heated structure with a vented lid and adjustable, constant, thermostatic temperature control. It provides a warm, humid environment to help seeds germinate and cuttings to root quickly.

  as warmth will improve the success rate of rooting

Cuttings: hardwood

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.

of evergreens in late summer:

• Cut out the soft tips and then use the standard method for semi-ripe cuttings (see our guide below)
• Make sure that you remove lids or plastic covers from the cuttings regularly to control humidity
  

  The concentration of water vapour in the atmosphere. This affects the rate at which plants transpire (lose water from their leaf pores), which in turn affects how much water their roots absorb from the soil. If air humidity is low, plants transpire quickly and become at risk of wilting if water is lost from the leaves faster than it can be absorbed by the roots. Different plants require different levels of humidity to thrive. Many tropical houseplants need high humidity and are best grown in a steamy bathroom, misted regularly or placed on a saucer of damp pebbles. In a greenhouse, humidity can be raised in hot weather by damping down (wetting) the floor or overhead misting.

  (if they are soggy for long periods, they will rot and drop leaves)

Cuttings: semi-ripe

Propagating by seed

Hollies can be grown from seed, and this method works well for species, such as common holly, Ilex aquifolium, as the resulting seedlings

A seedling is a young plant grown from seed.

will all be similar to the parents. If you try growing a named cultivar

Gardeners often use the word variety when referring to a specific plant, but the correct botanical term is 'cultivar'. Whichever word you use, it means a distinctive plant or plants, given a specific cultivar name and usually bred to enhance certain characteristics, such as flower or fruit size, colour, flavour or fragrance, plant size, hardiness, disease resistance, etc. Additionally, it is worth knowing that, botanically, variety has another meaning - it refers to a naturally-occurring distinct plant that only has slight differences in its looks. For example, Malva alcea var. fastigiata differs from typical plants by having an upright habit.

(such as a variegated

Variegated means having leaves or other plant parts with streaks, blotches or patches of different colours. Typically, these would be a combination of two colours, such as green and gold or green and white.

plant), the seedlings may be quite different from the parent plants.   

• Collect the ripe berries in autumn and extract the seed by hand
• Sow the fresh seeds in pots or trays and then place outdoors in a coldframe or at the base of a house wall (where it is sheltered from the worst of the rain) to expose the seeds to winter chilling – this helps to break seed dormancy
  

  Dormancy refers to a period of inactivity in plants, during which they slow down or stop their growth, conserving energy and resources. This is a natural process that helps them survive harsh conditions, such as winter or drought. Dormancy in seeds is a mechanism that prevents them germinating until environmental conditions are favourable for growth.

• Seeds that have been stored will need cold moist stratification. To do this, mix the seed with damp sand and place in a tied plastic bag in the fridge for three months before sowing

Trees and shrubs from seed

Hollies are usually trouble-free; however, there are a few things to watch out for.

• Premature leaf drop and defoliation may be caused by holly blight disease. However, do remember that it’s common for evergreen hollies to lose some leaves in spring, especially after a cold winter.
• Hollies are prone to honey fungus. Where there is leaf loss and dieback that can't be accounted for by holly blight and weather damage, it’s worth checking the roots for signs of the fungus.
• Black deposits on the leaves (sooty mould) would suggest the presence of cushion scale.
• Yellowish-white or yellowish-purple blotches on the upper surface of older leaves can be caused by holly leaf miner.
• Hollies struggle on wet soils. The excess soil moisture is damaging to the roots and results in poor growth or dieback. Consider improving drainage or moving the shrubs to a better-suited position.
• New shoots can attract aphids.

If your holly doesn’t seem to be thriving and you are not sure what is wrong, the guides below are a good place to start.

Brown leaves on woody plants

Why has my tree or shrub died?

Or, if you’re a member of the RHS, you can use our online Gardening Advice service, via MyRHS.