May is one of the most forgiving months to start gardening. The soil has had time to warm up properly, the risk of a late frost is largely behind us, and there is still plenty of summer ahead for plants to establish and get going. It is also the time of year when garden centres are at their best, well-stocked, and with staff on hand to help anyone who is not sure where to start. With May offering some of the best planting conditions of the year, as part of its ‘Make it Bloom’ campaign, British Garden Centres has put together a guide to the flowers, bulbs and seeds that will give gardens the most rewarding summer season.

Bulbs and tubers

Dahlias: May is the right time for dahlias. Buy them as potted plants, get them in now, and they will flower from July right through to the first frosts. One of the hardest-working plants in the summer garden that will reward you with a colourful display through to early autumn.

Gladioli: Gladioli corms can go in throughout the month for statuesque colour. Planting in small batches every couple of weeks extends the flowering season. They work well at the back of borders, and the cut flowers last well indoors.

Begonias: Potted begonias can go outside now that the risk of frost has largely passed. Reliable for sustained colour through summer and into autumn, with very little attention needed once established.

Canna lilies: Cannas do well when planted in May as the ground warms. The large leaves give immediate presence in a border or container, and the flowers that follow are bold and long-lasting, giving an almost tropical feel to your outdoor space.

Lilies: At this stage, it is better to buy lilies as potted plants rather than bare bulbs. They go straight into borders or large pots, establish quickly, and flower from midsummer with little maintenance. Plant now into your garden for a fragrant summer with this quintessential seasonal bloom.

Seeds

The soil temperature in May makes it one of the best months for direct sowing into your beds, borders or containers. Your seeds will germinate reliably now that the risk of frost is low, and there is enough growing season for most varieties in your garden centre to reach their potential and explode into a kaleidoscope of colour. Here are some of our favourites:

Cosmos: Cosmos can be sown directly outside in May and will be in flower within about 12 weeks, giving you dainty daisy-like blooms. It fills gaps in borders well, keeps producing blooms if regularly deadheaded, and is one of the more forgiving things to grow from seed.

Sunflowers: May is a good month to sow sunflowers directly into the ground for a ray of sunshine later this year. The soil is warm enough for fast germination, they grow quickly, and both giant and multi-headed varieties will be flowering by midsummer.

Nasturtiums: Nasturtiums do well when sown outside in May. They are not fussy about soil conditions, need little watering once established, and flower steadily all summer without much intervention. Not only are they colourful, but they can be eaten with the leaves, providing a peppery kick to salads.

Sweet Peas: There is still time to sow sweet peas directly outside this month. Supports should go in at the same time, so your plants have something to climb. Even a late May sowing will produce flowers and fragrance from late summer.

Marigolds, Lobelia and Petunias: These are better started under cover or in a propagator in May, then hardened off before going outside. They should not be moved out until night temperatures are reliably mild, but start now, and you’ll have beautiful plants all through the summer weeks.

Perennials

Container grown perennials can be planted throughout this month. The ground is warm in May, establishment is quick, and there is plenty of season left for plants to settle in and perform.

Geraniums, Astrantia and Oriental Poppies: All three of these establish well in May and are ideal for summer blooms in your garden. Oriental poppies in particular can put on a good show in their first season, so plant now, and you will not be disappointed.

Peonies: Potted peonies are a great option and can go in during May. They are slow to establish but exceptionally long-lived, and the flowering display in later years makes them worth the investment. The main thing to get right is planting depth; the crown should sit just below the surface, no deeper, or they will not flower.

Lupins: Potted lupins planted in May will often flower in their first season. The spikes come in a wide range of colours, they are good for pollinators, and they prefer well-drained soil in a sunny spot. Also popular at RHS Chelsea, these beautiful blooms will give you an on-trend look this summer.

Salvia: Hardy salvias establish well from a May planting, flower from midsummer over a long period, and are a magnet for bees. They work well alongside most other summer perennials to give a cohesive display all summer long.

Echinacea and Rudbeckia: Both flower from July into autumn in a sunny border. A May planting gives them the full season, and both return each year, with their cone heads loved by pollinating insects and keeping your garden buzzing all summer.

A lot of people come in at this time of year feeling like they’ve already missed the boat, but that’s really not the case. May is a brilliant month to get started, whether you’ve been gardening for years or you’re just finding your feet. Your plants will establish quickly, and you will see results much sooner than you might think, giving you a blooming summer.

Visit https://www.britishgardencentres.com/make-it-bloom/ for more information and more inspiring gardening tips.

British Garden Centres (BGC) is the UK’s largest family-owned garden centre group with 79 centres around the country. The group is owned and led by the Stubbs family, who also own and operate Woodthorpe Leisure Park in Lincolnshire.

BGC was launched in 1990 with the opening of Woodthorpe Garden Centre by brothers Charles and Robert Stubbs. Since 2018, it has expanded rapidly with the acquisition of 50 garden centres, allowing it to grow from its heartland to the business it is now, with 79 garden centres spread from Carmarthen to Ramsgate, Wimborne to East Durham.

The group has a team of over 3,500 colleagues working across the garden centres, restaurants, growing nurseries, distribution centres, Woodthorpe Leisure Park, and Woody’s Restaurant & Bar.