How to look after hedges: the ultimate guide to planting, fertilising and trimming

What is a garden without a hedge? Almost like a summer without any sun! Hedges provide a natural fence, offering privacy and protection against the elements, and giving birds a safe place to hide out between the leaves. Our guide tells you everything you need to know about planting, maintaining and trimming hedges. So what are you waiting for?

What type of hedge is right for my garden?

Not all hedges are created equal. When deciding which one to plant in your garden, you need to ask yourself what’s important to you and when you want to plant your hedge.

Do you want a hedge that’s easy to maintain? Then you’re best off choosing a non-deciduous (evergreen) variety like privet or yew. Deciduous hedges lose their leaves when it gets cold and generally require more upkeep. If you want a high hedge, your best bet is Thuja (Arborvitae) or cherry laurel. Hornbeams also grow tall very quickly. Or if you prefer a lower but denser hedge, box (Buxus) is just the thing. Meanwhile, rhododendron might be right if you're looking to add a splash of colour to your garden and you're not afraid of the extra work involved. Depending on the type, the greenery will transform into a white, pink or lilac sea of flowers in the first rays of sunshine.

The right time to plant a hedge

Planting a hedge is easier than you think. But to help it bloom and grow, you need to plant it at the right time of year – which depends on the type of plant you’ve chosen. In general, mild spring weather or the start of autumn are best. Hedges that are sensitive to the frost, such as cherry laurel or yew, should be planted in the spring. This will give them until the winter to grow and allow them to survive the cold.

How to plant hedges

Step 1: Prepare the soil for planting

You can skip your arm workout today – digging up the soil for your hedge will be more than enough exertion! The depth and breadth of the ditch you dig should be based on the roots of your plant, i.e. it should be around 1.5 times bigger than the roots. To ensure the hedge grows straight, put a piece of string around the area you want to dig up. To make your hedge as thick and dense as possible, it’s best to plant three to four plants per metre. So get your shovel and start digging. Once you’ve finished, loosen up the earth at the bottom a little – this will give the roots more room to spread out.

Step 2: Give your plants a new home

Once you’ve finished digging your ditch and have loosened up the earth, it’s time to put your plants in the soil. They will probably come in either burlap cloth (to protect the roots) or in a plastic container. If burlap cloth is wrapped around the roots, you can leave the plants in it when you insert them into the ditch. Then untie the cloth, fold down the sides and bury it in the soil. To prevent the root balls from falling apart, the plants should not be moved again. Cover two-thirds of the roots with soil and water. Then insert the rest of the soil and carefully even it out with your foot to ensure the earth is well anchored. If your plants are in plastic containers, remove them before putting them into the ditch, then water them well and cover them with earth.

Step 3: It's spray time!

Once you’ve planted your hedge, you need to take good care of it. If you want a beautiful hedge, you need to be attentive. This means one thing above all: watering it. To begin with, every three to four days is a good rule of thumb. Over time, you can probably increase the periods between watering. Your plants should get 10 litres of water for every metre in height. Of course, the exact amount of water they need also depends on the soil and type of plant – but this rule will enable you to make a rough estimate. So, if your hedge plants are half a metre high, approx. five litres of water per plant should suffice. For older hedges, regular watering is no longer necessary because of their deep roots, and you should only need to water them during long dry spells. If you can get in the habit of watering your hedge in the morning, you’ll be doing both yourself and your plants a favour. The soil is cooler in the morning, so the water doesn’t evaporate and can really reach the roots. When watering, direct the water stream right at the soil. The leaves will then take what they need from the earth. Watering the leaves directly could have an adverse effect and potentially encourage fungus diseases.

Step 4: Fertilise your hedge

You can help your hedge to grow by fertilising it in the spring and/or in the autumn. In most cases, it’s enough to add a little mature compost at the foot of the plant. Simply sprinkle it on the soil and rake it a little. For deciduous hedges and those with rotting leaves, such as privet, you can also use the leftover foliage and branches from trimming as fertiliser. After trimming, simply rake a little foliage into the soil beneath the hedge. More demanding plants such as rhododendron need acidic soil. To create this environment, you can add peat to the earth. You can also use horn shavings for fertiliser.

Step 5: Trim your hedge like a pro

A hedge is a bit like human hair: to help it grow and look good, you need to cut it from time to time. Depending on the condition and age of your hedge, it may be a question of simple maintenance or shaping, or moderate to radical pruning. Whatever your aim, it’s easiest with a pair of electric hedgecutters. For each cutting technique you want to try, you should select the appropriate teeth spacing (the distance between the individual teeth on the cutter blade).

Light pruning:

You should give non-deciduous (evergreen) hedges a light prune once a year, ideally between May and August. Deciduous hedges should ideally be trimmed twice a year, once in spring and once in late summer/early autumn. It’s best to wait until the main bud break to do the second trim, when the newly grown buds are fully developed and the hedge isn’t growing quite as much. That way the cut will last a little longer. Dry, overcast and frost-free days are ideal for trimming work; strong, direct sunlight could damage the shoots.

For contouring and light pruning, a pair of cutters with a small teeth spacing is sufficient because you’re mainly cutting young, thin branches. Ideally, you should trim your hedge in a trapezoid shape, i.e. the bottom branches should be longer than the top ones to ensure that all parts of the hedge get plenty of light. You can clip approx. 10–15 cm of the newly grown shoots straight across. To make sure the hedge isn’t crooked, you can again use a piece of string to guide you.

Moderate pruning:

for this type of trim, you should make sure that the teeth spacing on your cutters is bigger than the thickness of the branches. It’s best to work on frost-free days and cut back the fruit-bearing branches by as much as two-thirds. By doing so, you can remove the competing shoots, so the branches can again sprout buds effectively. For hedge plants that stem from trees, such as the field maple or hornbeam, you can prune three-quarters of the shoot tips in the first year. This will help the branches grow more widely/densely and make for a thicker hedge.

Hard pruning:

sometimes, older hedges need more radical pruning to restore their glory days and close over any gaps. Frost-free winter days are perfect for this type of work. It’s best to use cutters with a large teeth spacing and a powerful motor. Prune back the branches to the thickest trunk and they will grow back more densely in the spring.

My hedge has gaps in it. What should I do?

If your hedge has gaps in it, it may only need a little more sunlight to help close them. Simply trim back the bordering branches that are shading the problem areas. If a gap is fairly big, try crossing two neighbouring shoots over the hole – horizontally or diagonally – with the help of two bamboo sticks. Then trim the tips of the shoots slightly and see what happens. This should stimulate growth and help the gap to close over. If the shoots aren’t long enough to do this, the other option is to do more planting. Choose plants that are just as high as the rest of the hedge, or it will take too long for the gap to.