4 Signs it’s Time to Replant your Hedge

Hedges are a basic garden feature. They create privacy and a sense of enclosure, providing protection for people and plants from cold winds. So we want them to look good, but often they don’t. Sometimes a careful trim will bring them back, but sometimes an older hedge is too far gone to be saved. How to tell the difference?

A hedge should last at least 30 years, and some gardens have hedges 100 years old or more. Partly it depends on the plants used – if they can be trimmed hard back they can have a longer life – but it also depends on the maintenance given, and how the hedge was developed when young.

Here are some things to look for that will tell you if time is up for your hedge, or if it can be salvaged. If you do put in a new hedge, some of these problems can be prevented, so your new hedge will ook good for longer than the old one did.

Dead areas – if you have a lot of dead in a hedge, it’s probably time to replace it
Gaps where plants have died – it is always hard to fill these gaps in mature hedges – sounds like time to replant
Bare at the base – once a hedge thins at the bottom, there is no recovery. Replanting time
Grown too wide – sooner or later paths and drives can be obstructed. For most hedge plants, that means it needs replacing

Dead areas

There is dead, and then there is dead. If you have brown areas on the face of your hedge, take a closer look and see why. Is the brown all attached to one branch, or is it scattered? Has a plant died, so that all its interlaced branches are now brown? Are there signs of insect damage, or disease? Black, brown or reddish spots on the leaves, or growths on the stems, can indicate a disease. Bagworms will attack some hedge plants, and their nests made of twigs will be visible hanging on the branches.

If a whole plant, or several, have died, then once you take it out you will have gaps, which we will talk about lower down. If it is just branches, then often you can remove these, and the surrounding live parts will grow into the spaces in a couple of years or less, depending on their size. Obviously smaller spaces fill more quickly, and you can protect against big gaps from branches dying by trimming in all directions, not just upwards, so that the branches grow out horizontally, not in long sweeps up the hedge.

Gaps where plants have died

If you have had to remove a dead plant, or perhaps you have an older hedge that has already lost plants, these can sometimes be replaced with new ones. To get back to a perfect, uniform surface you need to know what the plants are, which can be tricky, but if you plant something similar the color and texture difference might just be ‘interesting’ – it depends on what kind of person you are. Plants beginning to die out could be a sign of an old hedge, so it can often be better to replant from scratch than keep trying to fill in gaps.

There are two key things for filling gaps – use good-sized plants and dig planting holes that are as big as possible. Set the new plants inside the hedge, so that they can grow out and fill in the space. Don’t plant them on the edge, or they can never grow properly.

When you are planting a new hedge, buy a few extra plants and put them in another part of the garden. Trim them when you trim the hedge. Then if you lose a plant or two from your hedge, you can use these spare plants. They will match perfectly, be the same age, already have some density and structure, and be used to your garden. It makes sense.

Bare at the base

This is a classic problem with hedges that have been trimmed badly. There really is no simple solution on an established hedge, so if you need that coverage and privacy it is time to plant a new hedge. This problem develops when a hedge is trimmed evenly all over. The top always grows faster than the bottom, so if you trim evenly it is inevitable that the top grows wider. Then it shades the bottom and steals food reserves, weakening the growth further. Soon the lower branches are dead, and the growth of your hedge migrates to the top.

With your new hedge, don’t make the same mistake. The face of a hedge should slope slightly inwards, so that light, water and nutrients reach the lower branches. To achieve this, you need to trim more from the upper parts than from lower down. That’s all it takes, it’s simple, but often not understood by novice trimmers.

Too wide

Over time, hedges grow. It is not possible to keep them to zero growth, although we can get close to it with regular trimming. The less often you trim, the quicker they will grow wide. Suddenly you find your car brushing against the hedge along the drive, or you can’t walk down the path anymore. Beds in front of the hedge become engulfed, and neighbors complain they can’t get down the sidewalk.

It depends on the type of plant used to make your hedge, but with most evergreens, particularly conifers, like Thuja Green Giant, Leyland Cypress, or Emerald Green Arborvitae, cannot be cut back into branches with no leaves on them. That is why regular trimming – little and often – is the best. If you have a wide hedge, you can cut back as hard as you can, always leaving some green, and then repeat that once it thickens up. This way you can certainly get back a foot or so. If the problem is bigger than that, this is another signal to replant – you will be amazed how much garden space you recover!

Some plants, like most broad-leaf evergreens, and conifers like yew trees, can be cut back to bare wood and they will re-sprout. This is why we sometimes see yew hedges that are hundreds of years old. The technique to reduce the spread of plants like this is simple. Cut back one side very hard, leaving the other side alone. In a year or two the cut-back side with have re-sprouted and be lush and green. Now you can do the other side. The whole process takes 3 to 4 years, but its still quicker than replanting. Pity it doesn’t work for everything! For other plants that have outgrown their allotted space, the only solution is to plant a nice new hedge.