How to grow perennial plants
Perennial plants provide flowers in our gardens year after year. There’s a huge range to choose from, with plenty for every growing condition and for flowers at every time of year. Many are easy to grow and low maintenance, thriving in both borders and containers.
- Most are easy to grow
- Plants last for many years
- There are options for every situation and soil type
- Best planted in autumn or spring
- Make new plants by division, cuttings or seeds
All you need to know
What are perennials?
Perennial plants live for many years and come in all shapes and sizes. These versatile and diverse plants fill our gardens with colourful flowers and ornamental foliage and are the mainstay of most borders. Many are hardy and can survive outdoors all year round, while less hardy types need protection over winter.
In a gardening context, the term perennial is used to describe long-lived plants without a permanent woody structure, to distinguish them from trees and shrubs (although botanically speaking, trees and shrubs are perennials too).
There are two main types:
- Herbaceous perennials – these die back to the ground in late autumn. The roots survive over winter and the plants re-sprout every spring. Examples include delphiniums, hardy geraniums and hostas.
- Evergreen and semi-evergreen perennials – these keep their leaves for most, or all, of the year. Examples include bergenias, epimediums and hellebores.
Choosing the right perennialsThere are perennials to suit any style and size of garden. There are options for all soil types and growing conditions. As these plants can live for many years, it’s worth choosing the right ones to suit your garden, so they will grow well and look great.
Use the links below to help you choose suitable perennials for your conditions:
Plants for chalky soil
Plants for clay soil
Plants for sandy soil
Plants for cold areas
Plants for under trees
Plants for shade
Plants for steep slopes
Plants for moist soil
Plants for coastal areas
Rock garden plants
Getting the right look
Consider what you want from your perennials when you consider buying them. For instance, do you want to colour-theme your border, or create an exciting mix of contrasts? Or to reate a naturalistic or exotic planting scheme? Here are some pointers to help you choose:
- Flower colours – you can choose flowers in every imaginable hue, from gentle pastels to vivid, exotic shades.
- Foliage - is available in wide ranging forms and colours to provide interest throughout the growing season. Foliage can often last much longer than flowers, so its colour and form is an important consideration when selecting a plant
Season of interest – there are perennials for every season, although the majority flower in spring or summer. To keep your garden full of interest all year, include some that flower in autumn and winter too.
Size – perennials come in all sizes, from low ground cover to towering spires, and everything in between. Keep your borders interesting by including a range of heights.
Shape – you can choose from low horizontal ground cover to tall verticals, or neat compact clumps to vigorous spreaders that will fill gaps quickly.
Evergreen or herbaceous – do you want foliage all year round (evergreen) or plants that die down in late autumn and sprout afresh every spring (herbaceous)? A mix of both will keep borders interesting across the season. For ground cover, evergreens are best as their year-round mat of foliage deters weeds.
- Wildlife-friendliness – many perennials attract wildlife, providing nectar-rich flowers, seeds for birds, and shelter for small creatures.
Perennials are available all year in containers. You can buy a wide range in garden centres, online or from specialist nurseries. Smaller, cheaper plants are often available in spring, which is particularly useful if you have a large area to fill. These may take a year or two to reach full size.
How and what to buy
A few perennials are sold as dormant bare-root plants, usually in spring, by mail order. Bare-root plants are economical and eco-friendly (no plastic pots), but areless readily available and restricted to a select few perennials which tolerate being bare rooted, including peonies, astrantias, sea holly and astilbes.
Where to get ideas and advice
To explore and narrow down your potential planting choices, you can:
Visit gardens with lots of perennials, such as the RHS Gardens, where all the plants are labelled, so you can note down your favourites.
Ask at nearby garden centres, which should offer a range of perennials that do well in your local conditions.
Browse our perennial plant profiles for photographs and plant descriptions. You can also refine your search by specifying growing conditions, flower colour, season of interest, and more.
Visit a specialist nursery, in person or online.
When to plant
- Good-sized hardy perennials are best planted outside in autumn or spring.
- Bare-root plants, young plants and plug plants are usually only available in spring, and are best potted up straight away into containers.
Where to plantThere are perennials to suit all growing conditions and types of soil – check labels when buying to make sure you put the right plant in the right place. See our guide to soil types.
Hardy perennials grow well outdoors all year, but some from warmer climates suffer in winter and need the shelter of a warm wall or greenhouse and well-drained conditions.
If you have a particularly cold or exposed site, see our guide to the hardiest hardy perennials.
Most perennials can also be grown in large containers.
Prepare your soil
Weed the area thoroughly before planting – if weeds are left, they can spread in among your perennials, which makes them trickier to remove.
Most perennials are easy to plant and settle in quickly and reliably. See our guide to planting perennials.
How to plant
You can also plant perennials in containers, either singly or with other plants. It’s simple and takes little time – see our guide to planting up containers.
Bare-root plants, young plants and plug plants are best planted into containers initially, until they are larger and growing strongly. They should be ready to plant into borders after a few months.
What are plug plants?
These tiny plants, usually just a few centimetres tall, are grown in modules and often sold by mail order. Plant them into slightly larger pots as soon as they arrive - they should grow quickly and soon be ready for planting outside.
WateringWater newly planted perennials regularly for their first year, until they’re settled in. After that, most only need extra water during long dry spells.
Perennials in containers should be watered regularly during the growing season, and especially in hot weather.
Groundcover perennials in dry soil beneath trees may also benefit from additional watering in summer.
Most perennials in borders need no additional feeding, but if the soil is particularly poor, you could add a well-balanced fertiliser, such as Growmore or blood, fish and bone, in spring.Apply a mulch of garden compost or well-rotted manure to the soil surface annually in spring, to enrich the soil.
Perennials in containers should be given a general fertiliser during the growing season.
It’s best to weed between perennial plants regularly, so weeds can’t get established or scatter their seeds. Mulching the border with garden compost in spring will help to deter the germination of annual weeds.
Many tall perennials need staking to hold the stems and flowers upright. Plants with heavy flowers, such as peonies, also benefit from support, as do those in windy sites.
Supports should be put in place in spring, so the plants grow up through them and hide them – see our guide to staking perennials and watch our video on supporting perennials.
Winter protectionSome perennials from warmer climes aren’t hardy in the UK and can’t cope with winter cold or wet – watch our video guide for advice on how to protect them. Check plant labels for hardiness.
These need additional watering and feeding, and repotting into larger containers as they grow. See our container maintenance guide.
Perennials in containers
To keep perennials growing and flowering well, or to prevent clumps getting too large, lift and divide them and replant into fresh compost every few years.
Caring for older plants
Perennials need little pruning. However, there are two instances where it is needed:
Cutting back – herbaceous perennials die back in late autumn and the dead stems should be cut off at the base before new shoots appear in spring. If you leave them in place over winter, some may look a little untidy, but will provide valuable shelter for overwintering beneficial insects.
Chelsea chop – perennials that are liable to flop can be reduced in height in late May to produce stockier plants or delay flowering.
Perennials, especially hardy ones, are usually robust and trouble free. However, look out for the following problems:
- Nibbled young shoots and holey leaves may be caused by slugs, snails, rabbits and mice.
- Yellow leaves (chlorosis) may be a sign of nutrient deficiency.
- Tall or top-heavy flower stems may flop over or break – put supports in place in spring.
- Plants may occasionally go into decline for no apparent reason – this often starts with browning leaves and may be caused by a disease such as phytophthora or pythium root rot.
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.