Garden guide: planning and planting a perennial display

Planting perennials: allow your creativity full rein

Planting a perennial display opens up wonderful opportunities in terms of design. Perennial plants grow and last for several years, and with the right planning, you can even put together a scheme that provides colour throughout the seasons by choosing plants that bloom in succession. This guide takes you through creating, planning and planting a dedicated bed for perennials, and it can also be used on a smaller scale or even in pots.

Choose which part of your garden you want to adorn with perennials. Think about how large you would like your perennial display to be, based on the space available and your broader garden design ambitions. You can create your perennial bed next to a wall or border or as an “island” bed in the middle of a lawn.

If you opt to install your perennial flower display in autumn, it’s really important to cover the earth with mulch after planting. This is because your newly installed plants are particularly vulnerable to frost damage, as they have not yet rooted into place. In very cold weather, freezing of the moisture in the ground can lead to frost heaving, which is when plants are disturbed and even uprooted by the movement of repeatedly frozen and thawing earth. This can cause severe damage to the plants. A generous layer of mulch after planting should prevent the earth from getting too cold, so your perennials are better protected.

Creating and planting a perennial display: step-by-step instructions

A perennial bed in your garden can take many forms and make plenty of impact. You could go for a rock garden, a gorgeous flower island on the lawn or create a bold splash of colour at the side of your house.

Step 1: choose location

Before you decide on the planting in your bed, consider its location. In particular, the light conditions – full sun, partial shade or deep shade – will greatly affect which perennials are most likely to succeed. Be prepared with this information before you start researching planting choices. The quality of your soil is also important: is it sandy or rich in clay? 

Full sun or part shade is ideal for a huge range of perennials, but beautiful planting schemes are also possible, even in a shady location.

Think about design

Do you want to theme your display or have a specific design concept in mind? There are many ways to approach this and many variables to consider. You could choose a single-coloured scheme or opt for boldness, or you might favour a cottage-garden style. When would you like your perennial display to be at its blooming peak? Do you want to create space between the flowering plants by adding grasses? Give your imagination free rein.

Garden bed design: remember point of view

If you are planning your perennial display against your house or a wall, you can design your planting in tiers, planting taller perennials at the back and smaller ones towards the front. You can apply the same principle to an island bed, though the taller perennials should be planted towards the middle. This arrangement means you can use a wide variety of perennials and showcase them all to best effect.

Add annuals to fill spaces

If there are gaps in your perennial bed, you can plant some annuals to add extra colour for the season. Otherwise, you can mulch bare patches of earth with dry grass cuttings, potting compost or mature leaf mould containing no weeds.

Clay soil, in particular, benefits from this kind of digging over before you start planting, as it allows water to penetrate more easily and ensures that the soil gets sufficient oxygen. You can also add sand and compost to improve drainage in heavy soil. Finally, rake the earth level.

If you’re planting a rock garden with perennials, look for plants that prefer to be dry. These alpine varieties originate from areas with challenging growing conditions, such as mountainous regions. They require excellent drainage, so you should also work some gravel or volcanic pumice into the soil when preparing the ground.

These reliable varieties of flowering perennials are popular with gardeners

Perennial bed concept: drought-resistant tiered bed

The following perennials are suitable for planting in a drought-resistant bed measuring 2.5 x 2 metres, and can be distributed as you prefer. The taller plants should be planted at the back and the smaller ones towards the front.

6x meadow sage (salvia nemorosa)‚ ‘Blue Hill’: 20-50 cm tall

9x Gaillardia ‘Burgundy’: 60-70 cm tall

4x silver feather grass (stipa barbata): 50-80 cm tall

3x Rudbeckia hirta ‘Prairie Sun’: 80-100 cm tall

2x Russian sage (salvia), ‘Blue Spire’: 100-120 cm

2x Round-headed leek (allium sphaerocephalon): 90 cm tall

Tips for planting and maintaining a perennial bed

Perennial types and planting density

How often should you water perennials?

We recommend watering your plants less frequently but more generously. Once or twice a week is usually enough, depending on the weather and the type of perennials you have planted. During periods of dry weather, you should water your plants more often; otherwise, their roots cannot grow deep enough, and the perennials will be less robust. Alpine and prairie perennials require less water than flowering perennials.

How many perennials can I plant in one bed?

Planting several of the same type of plant together looks good. We recommend that you do not plant more than 6-7 types of perennial in a bed. If you have more space, simply plant more of each type. When you break this down into square metres, it depends on the size of the perennials: the taller the plant, the fewer you should plant per square metre.

You can read more about this in the table above ↑.

Perennial bed maintenance

Once your perennials have rooted well and are settled, you will need to fertilise them regularly. The nutrients you add should be geared towards the plants in the bed and the soil conditions. Compost in spring and an organic long-term fertiliser are the best choices for both the plants and the environment.

If you want to harvest cut flowers from your perennials, you can do this at any time. Removing blooms will prevent the perennials from investing too much energy into producing seeds and thereby weakening themselves. Don’t cut everything back too drastically in autumn: some insects like to overwinter in dead stems, and birds will eat leftover seeds. You only need to cut back perennials that have large, soft leaves, as these tend to go pulpy and may rot. Secateurs work very well for cutting the plants.

Summary: planning and planting a perennial display

• A perennial display is a real eye-catcher for the garden. When designing your bed, you can give your creativity free rein.
• Spring is the best time to make a perennial display, as the perennials can be planted straight away.
• Before creating your perennial bed, you should draw up a planting plan that takes considers the location, soil quality and your preferred colours and flowers.
• The bed should be free of weeds and stones. Prepare the ground with compost and bonemeal.
• First, arrange the potted perennials to check your design, then soak the root balls in water and plant them in the ground.
• Perennials are usually rather low-maintenance. It is sufficient to water the bed thoroughly, up to twice a week, and to keep it clear of weeds.