How to grow

Choosing the right plants for your borders

A well planted border is the mainstay of any outdoor space. No matter size or situation, a mix of hardy border plants will bring year-round interest to any garden.

Choosing the right plants for your borders

A well planted border is the mainstay of any outdoor space. No matter size or situation, a mix of hardy border plants will bring year-round interest to any garden.

From a small urban space surrounded by hard surfaces to a country plot encircled by trees and hedge row, the open style of a mixed border can be adapted to suit any planting space. With such a wide range of hardy plants for borders there are plants to suit all tastes, spaces, planting styles and colour schemes.

Only the size of the garden and existing elements within it will determine the shape and size of your border. A traditional English perennial border will reach over 2m deep. These days, with most of us working to a much smaller scale, borders up to 90cm deep make the most sense, but really, the trick is to determine how much of a lawn you really need and work with the space you've got!

No matter the size you are working with, you will achieve great results by choosing a range of plants, ensuring a good mix of varying heights, textures and season of interest, to create year-round balance. The best mixed borders are made with a balance of border perennials and border shrubs.

Shrubs, particularly evergreen types, provide year-round shape and structure, while herbaceous perennials provide seasonal cover and flower colour. You really don't need a lot of space. Did you know dwarf alpines make excellent small perennial plants for borders?

perennial border

Browse our wide range of perennial border plants, which can be bought as bare roots, plugs and potted plants. Thompson & Morgan's selection of shrubs for borders offers something for all seasons and all spaces. They are all very simple to plant using the same basic principles. Keep reading to discover all you need to know about choosing the right perennials and shrubs for your borders. For more information, take a look at our step by step guide on how to plant a mixed border.

Bareroots Vs. Plug Plants Vs. Potted Plants

Bareroot plants:

  • Are cost effective
  • Can be planted October to March (depending on seasonal conditions)
  • Are easy to plant
  • Are quick to establish
  • Bareroots generally come as dormant or shooting plants with no soil at the roots. Perennials are supplied as root sections loosely packed in compost or sawdust.

Perennial plug plants:

  • Are cost effective
  • Initial sowing and growing has been done for you
  • Wide range of options
  • Require some growing on but allow a lot of plants to be produced for setting out in the garden
  • Are quick to establish

Hardy potted plants:

  • Can be planted all year round (autumn to spring will offer the most favourable conditions)
  • Create an instant impact in your garden, when planted through the growing season.
  • Potted plants, particularly larger ones, are generally more expensive.
  • They may require extra watering and attention while establishing in the first season.

When your plants arrive

young perennial plants

Bareroot shrubs and perennials

Stand bare root shrubs in a bucket of water to soak for an hour. If you can't plant them immediately then heel them into a temporary location, or plunge the roots into a large trug of damp soil to prevent them from drying out. Keep them in a frost free spot to protect the vulnerable roots from the cold. They can be kept like this for a few weeks if necessary.

Bareroot perennials are sent out through winter and early spring and should be ok for a few days in their packaging but ideally should be potted on as soon as possible on delivery. Given protection from the worst winter frosts and wet weather, they can be planted outside if the ground is not frozen or waterlogged, but they will be slower to get started and you may experience some losses. Ideally they should be grown on in a cool greenhouse, cold frame or cloche or on a cool windowsill. They can then safely be planted out as nicely sized young plants after the first frosts. If bare roots seem dry on arrival, soak for an hour in a bucket of water before potting on.

Plug plants

Plug plants should be unpacked immediately on arrival and potted up into 7cm diameter pots. If plugs are dry at the roots, soak the roots in water for 30 mins before planting them up. Grow them on in frost free conditions, such as a cool windowsill or greenhouse, until they are well grown. When all risk of frost has passed, gradually acclimatise them to outdoor conditions over 7-10 days, before planting them outside in their permanent positions.

Hardy potted plants

Potted plants can simply be watered and stood in a sheltered spot outdoors and planted at your convenience.

Soil preparation

digging a border

It's a good idea to prepare your soil in advance to allow it to settle well before planting. Make sure that the area is free from grass and weeds.

For a basic border you'll need to prepare a strip of ground that is around 90cm (3') wide, but where space allows it is best to add some curves to provide deeper planting areas and a more natural edge to the scheme.

Dig over the ground to a spades depth to break up the soil and mix in some well-rotted manure or garden compost, if you have some available.

Spacing plants

Planting distances will vary depending on the varieties selected, but as a general rule, when designing a mixed border, allow 30-45cm between plants of the same variety and 60-90cm between groups of different varieties.

If you have raised lots of plants from seed or plug you can perhaps afford to over plant for immediate effect, thinning out in future seasons. If you are purchasing larger potted specimen shrubs and perennials to plant the area, it pays to take a more considered approach leaving plenty of space for these more costly perennial plants to grow into.

Border design tips

  • Remember to have a selection of plants with different seasons of interest.
  • Set out your plants by height, tallest at the back of the border, shortest at the front.
  • Vary the height along the border to avoid a uniform, blocky feel.
  • Set out the larger shrubs singly and evenly along the space and surround these with groups of perennials.
  • Shrubs can also be grouped in clustered groups where space allows.
  • Set out perennials in either single variety groups or repeated blocks of the same perennial mix.
  • Odd numbers give a more natural feel when planting in groups.

Planting border perennials and shrubs

planting borders

Perennials and shrubs will last for many years. To reduce the need for weeding over that time you can plant your display through weed control fabric and cover the space between your plants with a decorative mulch of your choice. Bark chipping and coloured slate chippings are popular options. Alternatively any gaps can be filled with the odd seasonal bedding plant, a scattering of hardy annual flower seed or pocket of flowering bulbs.

Dig individual planting holes slightly deeper than, and twice as wide as the potted rootball or bare root. Simply spread out the roots of your bareroot plants and backfill the soil around them, aiming to set the growing points or shoot tips just below the soil surface.

You can tease some of the roots out of the rootball of potted plants before setting the plant in the hole.

When planting potted plants, always firm them in with your heel or balled fist to remove any air pockets. Set the surface of the rootball just below the soil line and cover lightly with soil. Do not set the stems of shrubs any deeper than they are growing in their pots.

Root wrapped and potted plants can be planted in a similar way. Trim you plants to the same height and rake the soil level around the base of the plants, to give you a nice finish. Finally water them well to settle the soil and get them off to a great start.



Over the first year you will need to keep them well watered, especially during dry periods. In future years, watering should only be need during summer dry spells. Where practical, it may be worth installing an automated irrigation system to make this task easier.

watering borders


Apply an annual application of bonemeal or slow release fertiliser each spring.


Perennials should be cut down in autumn as their foliage dies back, Some have ornamental seedheads or foliage that can be left through winter to add interest on a frosty morning.

Opt for slow growing and/or compact shrubs to avoid the need for regular pruning. Most deciduous shrubs can be pruned during winter and early spring while dormant. Evergreen shrubs are best pruned in early summer. Even if you get the timing wrong you will only loose flowers for one season, so don't panic!

Watch the video below to find out more about how to plant borders: