Holly Hedge Plants (Ilex aquifolium)

What are holly hedge plants?

The dark, glossy leaves of common holly, Ilex aquifolium, stay on the plant throughout winter. Its closely packed, thorny branches form a substantial boundary, with sheltered spaces where small birds can roost away from cold weather and predators. It can be clipped into a formal line or allowed a looser outline where space permits.

Why choose English holly for a hedge?

Holly grows more slowly when young than vigorous conifers such as Leylandii. Its slower growth makes it easier to maintain a clipped outline without the frequent cutting needed by Leylandii. The spiny leaves also discourage people and animals from pushing through a boundary hedge. Small spring flowers can be followed by red berries on female plants after pollination. These hedge plants are not selected as male or female, so some may bear berries and others may not. Even without berries, the dark green foliage gives the hedge a consistent appearance throughout winter.

How tall and wide does a holly hedge grow?

A holly hedge can be kept at 1.2 to 2.5 metres tall with regular trimming. Left unclipped, common holly eventually reaches 6 to 8 metres tall and 3 to 4 metres wide over many years. Expect 15 to 30cm of new growth each year once the roots are established. Growth is slower in the first couple of seasons while the plants settle in.

Where can I use holly hedging?

Holly suits a formal front-garden boundary where a neat, evergreen line is wanted. In a family garden, it can screen a seating area and provide nesting cover for birds, although the thorny foliage needs careful positioning away from children's play spaces. Use it as a backdrop for flowering shrubs in a mixed border, or plant a short run beside a driveway. In a small town garden, a clipped holly hedge can mark a boundary without the hard outline of fencing, although it takes time to develop into a full screen. Consider the spiny leaves when positioning the hedge close to a narrow path, gate or children's play area. Leave enough room to trim it comfortably and wear gloves when handling or cutting the plants.

Choosing a size

All our English holly hedge plants come in 9cm pots and are sold individually with a minimum order of 10 plants. The 60-80cm plants give more height at planting than the 30-40cm option. Whichever size you choose, check soil moisture regularly until the roots establish.

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When and how should I plant a holly hedge?

Pot-grown holly can be planted at any time of year, provided the ground is not frozen or waterlogged. Autumn and spring are ideal because the soil is naturally moist and the roots establish quickly. Prepare a weed-free strip and water the pots thoroughly before planting. Remove each container and place the rootball at the same depth as before. Backfill, firm gently and water slowly so moisture reaches the roots. Do not plant into a hole that remains waterlogged.

How many holly plants do I need per metre?

For a single row, space the plants 40 to 50cm apart. That works out to 2 to 3 plants per linear metre. A double row, staggered, gives a thicker hedge faster: use 3 to 4 plants per metre in total. The table below shows how many plants to order for common hedge lengths.

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Watering, feeding and mulching

Check moisture during dry spells while the hedge establishes. Rainwater can run off dense foliage, so inspect the soil rather than judging by the weather alone. Keep grass away from the root area and use mulch to help conserve moisture, leaving a clear gap around the stem. Feed with a general-purpose slow-release fertiliser in early spring to support steady growth.

Trimming calendar

Trim a formal holly hedge in late summer to maintain a clean outline. Earlier cutting can be followed by another flush of uneven growth. Before cutting, check carefully for active bird nests. Keep the lower part of the hedge broad enough to receive light. Wear sturdy gloves around spiny foliage and clear away clippings. Holly berries are ornamental and should not be eaten.