Carol Klein's favourite plant combinations
Carol Klein recommends some winning plant combinations to try in your garden
Putting plants together is one of the most satisfying aspects of gardening.
Effective combinations are restricted only by the simple rule that the plants we put together should enjoy similar conditions and be able to grow in each other’s company.
There are a few considerations to bear in mind. One of the first things gardeners think about when combining plants is colour. Not just about whether the plant is blue or yellow: think about what form the colour takes – are there big blobs of colour, as with peonies, or the small spots of colour we see with a herbaceous potentilla or a geum. A grass such as Imperata cylindrica ‘Rubra’ may have the same colour as an astrantia, yet it creates a totally different pattern and texture.
A variety of shapes can also help disguise other plants’ weaknesses. Use shorter, dense clumping plants like cranesbills and Lamium orvala to mask the knobbly knees of heleniums and asters.
Size is important, as is scale. If the flowers and leaves are the same size, the result can be monotonous. Don’t forget plant growth habits, either. It’s vital to not include thuggish plants that will rapidly expand beyond an allotted space and swamp their neighbours.
Finally, to give your plant combinations added impact, narrow down your plant palette. Use more plants but fewer varieties. Some of the most effective combinations feature as few as three plants, but are more effective because of their simplicity.
More planting combinations:
Take a look at some of Carol Klein's favourite planting combinations to try out yourself.
Dahlia and canna
A simple contrast of colour and form makes a dramatic statement. Dahlia ‘Taratahi Ruby’, with its cherry-red flowers, complements the bold, paddle-shaped leaves of Canna ‘Musifolia’. Later, it too will produce similarly coloured flowers, but of a totally different form.
Dahlia ‘Taratahi Ruby’
Flowers: Jul-Oct. Height x spread: 1.3m x 60cm.
Canna ‘Musifolia’
Flowers: Jun-Sep. H x S: 3m x 1.5m.
Mullein and anchusa
Blue and yellow make a classic combination. The yellow mullein (verbascum) is a short-lived perennial, as is the accompanying anchusa. Of a similar height but contrasting formation the two mingle perfectly – the mullein’s ‘bee’ centre and the anchusa stems both being maroon.
Verbascum ‘Cotswold Queen’
Flowers: Jul-Aug. H x S: 1.2m x 30cm.
Anchusa ‘Loddon Royalist’
Flowers: Jun-Jul. H x S: 1m x 60cm.
Smoke bush, crocosmia and fennel
Early in the season, as the leaves of the smoke bush (cotinus) emerge, the bronze fennel makes low frothy tuffets and the crocosmia leaves create clumps of translucent, vernal green. Later as the cotinus leaves redden, the fennel will produce seedheads.
Crocosmia
Flowers: Aug-Sep. H x S: 70cm x 1m.
Cotinus
Flowers: Jul-Aug. H x S: 6m x 5m.
Foeniculum ‘Purpureum’
Flowers: Jul-Aug. H x S: 1.8m x 45cm.
Astilbe, aster and monkshood
In the shade of the dark-leaved bird cherry, Prunus padus ‘Colorata’, blue and white flowers exhibit a luminous quality. The frothy white fronds of Astilbe ‘Professor van der Wielen’ keep company with aster (Symphyotrichum ‘Little Carlow’) and spires of self-sown white monkshood (Aconitum ‘Ivorine’) add extra interest.
Astilbe ‘Professor van der Wielen’
Flowers: Jul-Aug. H x S: 90cm x 75cm.
Symphyotrichum ‘Little Carlow’
Flowers: Aug-Oct. H x S: 90cm x 45cm.
Aconitum ‘Ivorine’
Flowers: May-Jul. H x S: 80cm x 40cm.
Astrantia, geranium and bears breeches
Astrantia, a soft grey Geranium pratense seedling and an invading bear's breeches (acanthus), reflect each other’s colours while displaying different forms.
Astrantia ‘Glebe Cottage Crimson’
Flowers: Jun-Aug. H x S: 60cm x 30cm.
Geranium pratense
Flowers: May-Jun. H x S: 90cm x 60cm.
Acanthus spinosus
Flowers: Jun-Aug. H x S: 1.5m x 1m.
Daylily and bronze fennel
A textural contrast between the solid blocks of colour created by the daylily and the bronze fennel’s fine net make a simple but effective combination. This daylily has rust-coloured flowers lit with orange.
Hemerocallis ‘Stafford’
Flowers: Jul. H x S: 80cm x 40cm.
Foeniculum ‘Purpureum’
Flowers: Jul-Aug. H x S: 1.8m x 45cm.
Daylily and Bowles’s golden sedge
Hemerocallis lilioasphodelus is one of earliest of the daylilies to flower. Geranium pratense has flowered and soon asters, rudbeckia and helenium will add their weight.
Hemerocallis lilioasphodelus
Flowers: Jun-Jul. H x S: 1m x 40cm.
Carex elata ‘Aurea’
Flowers: Jun-Jul. H x S: 70cm x 45cm.
Fleabane and thrift
Mexican fleabane (erigeron) has seeded itself into every crack surrounding the sea thrift (armeria). The fact that its flowers change subtly from white to pink adds interest. The combination of soft ephemeral flowers and solid grey stone is as important as those of the plants.
Erigeron karvinskianus
Flowers: Jun-Oct. H x S: 30cm x 50cm.
Armeria maritima
Flowers: May-Aug. H x S: 50cm x 50cm.
Lady’s mantle, molinia and sea holly
The frothy foreground is provided by the tiny green stars of lady’s mantle (alchemilla) while the fine stems of the molinia grass make a curtain in the background, setting the stage for sea holly (eryngium).
Alchemilla mollis
Flowers: Jun-Sep. H x S: 60cm x 75cm.
Molinia caerulea ‘Edith Dudszus’
Flowers: Aug-Oct. H x S: 75cm x 60cm.
Eryngium x zabelii
Flowers: Aug-Oct. H x S: 80cm x 40cm.
Year Planner 2025 on sale
Starting to plan your gardening year? The Year Planner 2025 is packed with expert advice from the Gardeners’ World team, to ensure you have your best gardening year yet.
New podcast series
Join Monty and the team for advice on winter gardening, tulips, caring for birds, house plants and more in the new BBC Gardeners' World Magazine podcast series.
