Five steps to better borders

An autumn sort-out is perfect if your borders are looking tired and unbalanced, if there are shrubs that aren’t flowering, or perennials that have become congested. It's also the perfect opportunity to assess what you already have growing, and see if you can add a few new plants to create further interest. Don’t know where to start? Just follow these five simple steps.

1. Make a plan

When planning a border, the first thing to do is get your idea down on paper. Come up with a word to describe how you want your border to feel – ‘hot’, ‘bold’, ‘romantic’ – it’s to keep you focused on the final look. Measure the area, noting down all existing plants and marking the ones you want to leave in their present position. If you plan to alter the border’s shape or size, now's a good time to draw up any changes. Check where the sun rises and sets, as this will help you ensure sun-loving plants get the sun they need and shady spots are filled with plants that will thrive there.

When you go to the garden centre, always try to have a clear idea beforehand of what you're trying to add to the border.

Designing a border is all about layers. The tallest layer is for any tall trees you have space for – in a small garden you may need to skip this. The second layer is for smaller trees. Next comes shrubs, followed by perennials, and low-growing plants such as ground cover and small bulbs. Ensuring you have interest across all these layers will give you a great checklist when planning your space. When you go to the garden centre, always try to have a clear idea beforehand of what you're trying to add to the border.

2. Prune your shrubs

Pruning is an easy way to bring an overgrown shrubby border back to its former glory. Firstly, remove any dead, damaged and diseased stems, as well as crossing stems rubbing against each other. Next, stand back and look at the shrub to work out how you can make it more balanced. Look for a healthy side shoot that you can cut back to an outward-facing bud. You want to encourage new stems to grow outwards, rather than into the middle.

For a total rejuvenation, cut back all stems to 20-30cm from the ground, then give the plant a feed and mulch in spring.

Most deciduous shrubs, such as dogwood, smoke bush and spiraea, respond well to hard pruning in winter. Remove the lower branches of large shrubs and trees to reveal the main stems. This will transform a bulky shrub into a real feature, and let in more light and air. For a total rejuvenation, cut back all stems to 20-30cm from the ground, then give the plant a feed and mulch in spring. If you want to move a shrub, bear in mind that it may not survive the move. Relocate evergreens in October or late March, early April, and deciduous shrubs from November to March. Remember to keep them well watered.

3. Rejuvenate your perennials

Perennials can become congested over time, with all the vibrant, flowering growth on the outside of the clump and little going on in the middle. Other perennials can become thug-like and take over borders, killing less-vigorous plants. The best way to solve these problems is to dig them up and divide them. Done every few years, this will rejuvenate tired perennials and stop others spreading too much.

Divide summer-flowering plants in autumn or spring, while spring-flowering plants should be divided in summer to give them time to establish before the following year. Dig them up with a spade, taking care to keep as much of the roots attached as possible. Then push two garden forks, back to back, into the centre of the plant and use them as levers to tease the rootball apart – you could also cut through the middle with a knife or spade. When you replant your new bits of plant, make sure you keep them well watered. Divide rootballs by hand, or use two forks back to back if they're congested.

4. Remove weeds

In mature borders, weeds can hide among perennials and take hold before you realise. Annual weeds, like chickweed or hairy bittercress, are easy to remove by hand or by lightly hoeing, so get them before they set seed. Perennial weeds take more time and effort. The key is to remove all of the roots, which is sometimes easier said than done. Hoeing or digging up when they first appear will keep on top of them, and many perennial weeds can be gradually weakened and removed over time.

5. Treat yourself to new plants

Before you head to the nursery, make a list of the plants you already have, then assess your border. See how much space there is to fill and what your border is missing – perhaps it needs more colour, late-season interest or height? Don’t just splurge on lots of plants that will all flower at the same time, leaving you with nothing the rest of the year.

If you have lots of space to fill and a tight budget, try growing perennials from seed, or buy plants that you can divide immediately into two or three pieces, or that you can take cuttings from.

If you have lots of space to fill and a tight budget, try growing perennials from seed, or buy plants that you can divide immediately into two or three pieces, or that you can take cuttings from. Also sow annuals to fill in gaps while you build up your stocks. Early October is a great time to sow hardy annuals, such as poppies, cornflowers and pot marigolds for flowers next summer. Prepare the soil by adding compost and water well to help new plants to establish.