Pick of the best flowering perennials and shrubs for spring and early summer

Fill it with flowers!

There’s no shortage of blooms at this time of year, and with the RHS Chelsea Flower Show looming (commencing 21 May), focus is firmly on flowers in the garden during this wonderful season. But there are many people who look wistfully from the side-lines, wondering why their own gardens aren’t showing such splendour. So let’s take a look at the best flowering shrubs and perennials for a marvellous May. If you set yourself a target to plant one specimen each month, choosing something that flowers in that particular month, your garden would gradually fill with flowering interest throughout the year.

Perennials

The season of spring is shared by so many. In fact, there’s been a proliferation of perennials over the last decade or so. Now that we favour a full, ‘naturalistic’ look, with every space filled with lushness, perennials have taken centre stage. These plants just keep giving, and the dedicated work by breeders over a long period has ensured that most perennials are not just a ‘one trick pony’. Cut them back after flowering and many will give blooms right to the end of the summer. It's difficult to select the best flowering perennials out of so many beauties, but here's a starting point.

Find space for special plants!

Digitalis, or foxgloves, have been around for centuries but there are now at least 25 species.  For impact and beauty, they are amongst some of the best flowering perennials around. Digitalis purpurea and all its cultivars are truly  biennial in nature. They don’t flower in their first year. Many of the colourful and beautiful hybrids are best treated as short-lived perennials, whilst the more natural form will self-seed and pop up in suitable shady places.

Old favourites are improving all the time

Wallflowers, particularly the shrubby variety, Erysimum ‘Bowles Mauve’ are invaluable during spring, when the sight of flowers in profusion is a joy to behold. They can be trimmed back after flowering and encouraged to give more blooms and many will last for several years. Fill every available sunny niche with a fistful of bare-rooted wallflowers in the autumn – you won’t ever want to be without them when you view the results in spring.

See-through beauty

Verbenas, including the wildly popular Verbena bonariensis, are showing no signs of falling out of favour and are regarded as some of the best flowering perennials of their kind. The wiry-stemmed perennial verbena varieties are tall and medium height and because they are narrow, they can be planted anywhere in the borders. Classed as ‘see-through’, because they don’t obstruct the view of other plants, their luminescent purple flowers dance around in the sunlight from late spring right through until autumn.

Hardy geraniums for groundcovering mounds of wonder

The range of cranesbill, or hardy geraniums is growing! These are joyful, uplifting perennials that should be worshipped with reverence. So easy to accommodate, provided there’s a sunny site, the orderly clumps bear saucer-shaped flowers from May right through until autumn. But cranesbill, which come in shades of pink, purple, white and blue, comes with a bit of a warning: choose your varieties carefully. Some are thugs! They spread like mad and can engulf everything in their path. The basic form of pale pink Geranium macrorrhizum is a valuable plant in its own right, but maybe not for a small garden that needs to accommodate other perennials too!

Fill the gaps

Fillers such as Astrantia, known as Hattie’s pin cushion, are invaluable for providing little dots of flowering beauty throughout late May, June and then again at the end of the summer.  Then there are the magnificent blooms of Iris, some of which no longer just grace gardens in spring but have been bred for continuous flowering throughout the summer too. And luscious Lupins, of course, providing wonderful flowering spires in all sorts of colours including reds, oranges, white, purple, blue and many combinations in-between.

Flowering shrubs

Shrubs will never fall completely out of favour, despite the rise in popularity of perennials. They provide the backbone of the garden all year round, and spring brings the huge benefit of flowers too. We have already passed the main season of yellow-flowering shrubs including Forsythia and Mahonia. But there are many more beauties now gracing the spring gardens. Viburnum, for example, is an amazing woody plant that has many different forms. There are, in fact, up to 175 species of this versatile beauty that can produce generally white or pink flowers, plus berries later in the year.

Scent, beauty and style

Then there are the sweetly-scented Philadelphus which smell like oranges; Ceanothus with its incredible blue blooms; Daphne, with its scent to die for; Syringa, the lilac shrub which now has flowers in a range of mauves; the incredibly pretty Deutzia in all its various forms; Weigela, which is loved by bees; the glorious Hibiscus ‘tree hollyhock’ and Lavatera which now comes in many different forms.

So many opportunities, you’ll not be able to contain yourself!

Perfectplants.co.uk