Summer bulbs to illuminate the garden

These cheap and easy-to-use plants provide many possibilities in the garden, from extending the season to making showy container displays

A bursting container featuring a dahlia with a begonia and a petuniaSummer-flowering bulbs are some of the most rewarding plants and, particularly with some planning, they provide a wide array of possibilities.

When grown in containers (right), they offer a really flexible way to introduce colour, and sometimes scent, into the garden – I think a pair of bold, showy containers guarding a door or archway makes quite a striking sight.

Bulbous plants (I use the term loosely to include corms and tubers too) can also complement, accentuate or bulk out summer colour schemes, particularly if there has been space left for them in beds. Repeating them throughout a bed can really tie together a planting scheme through the repetition of their flowers and foliage.

Gladioli, lilies and dahlias are three of the most popular summer-flowering bulbous plants and for good reason – they are reliably colourful and good performers. Here are some favourites to try out.


Gladiolus murielaeGladioli

These corms can reach up to 2m (6½ft). Their form is particularly striking with upright spikes of colourful, open flowers. Strangely, few Gladiolus have been awarded AGMs. However, some notable selections that are worth trying out include: 'Plum Tart', a tall selection of up to 1.5m (5ft) with rich plum-purple flowers, and 'Green Woodpecker' which has red-marked, ruffled greenish-yellow blooms that can also reach 1.5m (5ft) tall.

However, I quite like the slightly different Gladiolus murielae (left), previously known as Acidanthera bicolor or G. callianthus, which has hooded, fragrant flowers of white and purple.

Gertrude Jekyll advised arranging gladioli in bands or ribbons throughout beds and borders, using them as a foil for rounded plants. She was particularly fond of the, now extremely rare, scarlet selection, Gladiolus × brenchleyensis. I think this could inspire gardeners in how to use them outside, as otherwise they can be tricky. Try combining them, like dahlias, with exotic plants and those with broad and bold foliage. However, they are certainly excellent as cut flowers and container plants – they could be used in pots in beds to replace lilies that have finished, continuing the season.



Lilium lancifolium 'Splendens'


Varied in size, like dahlias, from ankle height to around 2.2m (7ft), lilies are true bulbs. I would recommend trying AGM cultivars such as: Lilium lancifolium ‘Splendens’ (right), a black-spotted, orange-red selection; L. regale, a white and yellow coloured, trumpet-flowered lily; and L. ‘Grand Cru’, a brightly coloured cultivar with yellow flowers, stained red at the centre. Many lilies are fabulously scented. Lilies are great at being grown in pots and then dropped strategically into beds, as they can replace earlier flowering plants. The form and colour of lilies can often complement, so consider the colour scheme, for example white lilies complement silver-leaved plants beautifully.

RHS Advice on growing lilies in containers


Dahlia 'Pink Pastelle'Dahlias

These are actually tubers and come in many sizes and shapes, some reaching 2m (6½ft) or more. Some stand out: AGM-winning cultivars include: ‘Twyning’s After Eight’, a single-flowered cultivar with dark foliage and pure-white blooms; and ‘Pink Pastelle’ (left), a semi-cactus selection with flower heads of vivid shades of pink. However, I think there's something rather pleasing about the almost spherical pompon selections such as 'Small World', a creamy-white bloom. It's difficult to ignore the way dahlias are used at Great Dixter where, famously, they combine well with exotic plants such as cannas, phormiums and others with bold foliage. They are equally excellent at adding colour to mixed herbaceous borders, providing a striking addition to containers, and being deployed as cut flowers.

Read some expert RHS Advice on planting dahlias

Discuss this

for the site or to share your experiences on this topic and seek advice from our community of gardeners.

Get involved

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.