Let's be honest. Creating a perennial border is fairly easy. Making it successful is a little less so.

Aside from plants' adaptation to soil and exposure, there is also the question of colour, just as tricky! On that point, I will humbly abstain: I have lost count of the times I have moved plants grumbling "too purple!", "too red!", "too yellow!". So today I suggest we explore shapes… by offering a selection of perennial plants that, when combined, will produce striking contrasts, essential to avoid boredom. Indeed, plays of harmony and contrast with shapes are what truly create a border's composition and framework. After all, colour schemes are only "finishing touches" that will dress the border at a later stage 😉

Vertical forms: reaching for the sky!

Often graphic, these plants provide verticality and form a genuine link between sky and earth. They are perfect for enlivening a border that is a little too monotonous. There are varieties to suit all garden styles and sizes.

In well-drained soil, don't hesitate to plant Eremurus or Foxtail lily: relatively little known, it is a tuberous perennial with a very architectural habit. In the Veronica family, Veronicastrum virginicum are quite exceptional, proudly bearing their fine spikes like candelabra. Spectacular Kniphofias add an exotic touch and are unrivalled for warming up a border. For a more traditional, English-style garden, think of Delphiniums or Larkspurs. In shade or part shade, Cimicifugas are very effective. In a slightly "wild" vein, I also like Liatris spicata or Blazing star, which is furthermore very melliferous.

Pom-poms… more or less round

When thinking of spherical shapes, ornamental alliums are the first to come to mind. We all know 'Globe Master' and 'Purple Sensation'. They certainly make an impact! But there are many others: Pompon dahlias, globe thistles, and among the smaller, slightly less round types (great in drifts), Allium sphaerocephalon or round-headed garlic and the adorable Knautias and Sanguisorba 'Chocolate Tip'.

Stars: "Big star" or Milky Way

No need to be perceptive to guess that Asteraceae are, by nature, made to shine. Asters are my favourites in this respect. They have the advantage of being very diverse and can display either large flowers (such as the remarkable Aster pyrenaeus 'Lutetia') or spread a host of small stars like a Milky Way, as with the charming Aster 'Chloé'.

But as their flowering is rather late, the border can be complemented with other species such as Leucanthemums or oxeye daisies: simple but natural, Rudbeckias, very sunny, or Echinaceas, those fine Americans… In shade, Astrantia (which is not an Asteraceae but an Apiaceae) is perfect and offers a more refined style.

The airy ones: light mist, soft clouds or cotton candy

Whether they form a light haze, gentle plumes or generous "cotton candy" flowerheads, airy-looking perennials are precious. Depending on their size, they can be placed at the back or edge of borders but also as delicate curtains. Their suppleness and lightness complement more compact or rigid shapes very well. Very popular, Buenos Aires verbena is part of this group but needs no introduction… and others deserve your attention too.

Among the lightweights are Gypsophilas ('White Festival' is a marvel) and Thalictrums. Astilbes and Filipendulas are notable for their cloud-like inflorescences that can evoke cotton candy when pink… Still rather rare in gardens, Sanguisorbas hakusanensis and obtusa are charming as well!

The tousled ones — delightfully whimsical in a border!

What better way to catch the eye than a touch of fantasy? Plants with tousled flowers have plenty of that. We love their slightly extravagant look, always in good taste… provided they are used in moderation. A few examples: Monardas, certain varieties of Alliums and the highly horticultural forms of oxeye daisy.

And you, what are your favourite plants for composing beautiful, varied and dynamic borders?

For further reading, discover our advice sheet: "How to create a beautiful perennial border"