The back of the border is reserved for the lofty plants that can rise above the miscellany of plants towards the front.
As such, they're often shrubs or soaring perennials like cardoons. Their function is to bring colour, height and draw the eye to the back of the border.
After planting any shrub at the back of a border, be sure to follow these tips on making sure they establish well.
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Discover some of our favourite plants for the back of a border, below.
Elaeagnus are evergreen or deciduous shrubs. Though some are deemed a bit garish, there are quite a few relatively unknown types to grow. Elaeagnus commutata has gorgeous silvery foliage, while that of Elaeagnus parvifolia is green, with the leaves grouped together in a pretty shuttlecock arrangement. Both have lovely, honey-scented flowers.
If left unpruned each year, cotinus will eventually become lovely small trees. However, pruning them close to the ground each spring will produce a fantastic foliage display, suitable for borders. You can also do this with buddlejas and elders. Find out how to plant cotinus and buddleja in a border.
Exotic borders call for a touch of the unusual, which is where hardy scheffleras, like Schefflera rhododendrifolia, come in. Similar plants to consider include Tetrapanax papyrifer and Ricinus communis.
As the name suggests, the Japanese snowbell (Styrax japonicus) is grown largely for its pendulous summer blooms. In a border setting, prune annually to restrict its size.
If you're a fan of the cottage garden look, delphiniums are an essential plant to grow in your border. Most have cool-toned flowers, ranging from icy blues to deep purples. Find out how to cut back delphiniums for more flowers. Also consider statement lupins.
Eupatoriums are towering perennials with fluffy flowerheads that are especially popular with butterflies. Most flower in late summer and autumn. Species to grow include Eupatorium maculatum and Eupatorium ligustrinum, both of which reach over 2m tall. Check out more butterfly-friendly plants.
With its bright yellow flowerheads, fennel is sure to draw the eye to the back of the border. The feathery foliage brings further interest, and it's a brilliant plant for wildlife. You can even use the dried seeds to make herbal tea.
Most borders will be backing onto some sort of boundary, such as a fence or wall, so climbers like clematis can make good use of these vertical spaces. As well as flowering climbers, you could also grow climbers with interesting foliage. Check out these tips for training climbing plants.
With their wiry spires of flowers, veronicastrums are ideal for adding colour to the back of a border. They're marvellous plants to grow for pollinators; you'll find that the flowers are covered with bees. Check the height and spread when buying, as different cultivars will vary.
The cardoon, Cynara cardunculus, is a dramatic, short-lived perennial with flowers that look like giant thistles. Large, silvery leaves are followed by the towering flower stems, which are perfect for adding dots of colour. Great for bees. Leave the seedheads on for winter interest.