PERENNIAL PLANTING COMBINATIONS
There are literally thousands of plants to choose from and learning about them obviously takes years of experience so how can someone with a more basic knowledge produce successful planting schemes?
The best schemes are actually relatively simple so it is essential not to try to cram too much in. It’s a bit like packing to go on holiday; the temptation is to take a lot of stuff when all you really need is a pair of shorts and your sunglasses. The skill is in the editing. Draw up a wish list and then cut it in half at least. Learn to be ruthless because too many different plants will make an incoherent jumble, not a well thought out space.
There’s a lot of talk about plant combinations rather than merely looking at the merits of individual plants. What’s the key to successful combinations of flowering perennials?
Essentially what you are looking for are neighbouring plants that contrast with each other and the easiest way to do this is to categorise them by their forms and shapes.
Surely colour is the most important feature?
Actually no. The flower colour is usually quite fleeting whereas the structure or shape of the flower is far more enduring and remains even when the actual flower has finished and the seedhead is formed. Some seedheads can then last right through winter.
So how do you categorise the different flower shapes?
I use the following groups which are loosely based on an idea by Piet Oudolf, the champion of new perennial planting.
Spikes and Spires
Balls and Buttons,
Plumes and Feathers,
Umbels,
Daisies,
Haze
Spikes and Spires
Think of spires as punctuation within the planting. They introduce a rhythm of pauses and crescendos much like full stops and commas. They arrest the eye and create vertical accents contrasting easily with the less defined forms around them. Clumps or loose groups work much better than peppering a border with individual plants.
Digitalis ferruginea
Veronicastrum virginicum 'Fascination'
Cimicifuga simplex 'Atropurpurea"
Persicaria amplexicaulis
Calamagrostis x acutiflora ‘Karl Foerster’
Verbena hastata
Salvia pratensis ‘Lapis Luzuli’
Lythrum salicaria ‘Blush’
Lysimachia ephemerum
Lysimachia ‘Beaujolais’
Kniphofia
Balls and Buttons
These stand out clearly against softer shapes including plumes and hazes of stems and fine flowers like the grass Deschampsia cespitosa. Yet they are effectively transparent; understated yet vital smallish flowers that you look past to whatever is beyond. In winter they are often one of the most clearly defined seedhead shapes becoming dark spots against paler parchment coloured stems. Even daisies as they lose their petals become balls or buttons
Sanguisorba officinalis
Echinops ritro 'Veitch's Blue'
Phlomis tuberosa 'Amazone'
Allium hollandicum ‘Purple Sensation’
Knautia macedonica
Phlomis russeliana
Astrantia major ‘Roma’
Plumes and Feathers
These are typically made up of often thousands of tiny individual flowers. The result is a soft, form that is not too clearly defined and introduces a relaxed feel to a border. They work particularly well en masse.
Aruncus dioicus
Filipendula rubra ‘Venusta’
Calamagrostis brachytricha
Rodgersia ‘Chocolate Wings’
Umbels
This is the classic shape of so many wild flowers such as cow parsley and consequently they automatically lend a natural quality to any border. A slender framework like the skeleton of an umbrella supports gently rounded or globular heads made up of many small flowers. They work well as a counterbalance to the rigidity of spikes and spires and many retain their presence as seedheads.
Angelica gigas
Sedum telephium ‘Matrona’
Vernonia crinita
Achillea millefolium ‘Terracotta’
Eupatorium purpureum ‘Atropurpureum’
Smyrnium perfoliatum
Daisies
Daisies need no introduction. Mostly sun worshippers they tend to appear from midsummer onwards. They work well in drifts to provide blocks of colour within the planting scheme and then when the petals drop the central cone remains as a ball or button well into winter.
Rudbeckia fulgida 'Goldsturm'
Aster frikartii 'Monch'
Helenium ‘Moerheim Beauty’
Inula magnifica
Echinacea purpurea
Aster ericoides
Monarda ‘Beauty of Cobham’
Haze
This category includes the flower stems of grasses that create a soft veil, the very slender stems or tiny flowerheads of perenniuals that are airy and transparent. You look through them or other flowers like balls and buttons can dance through them or spires can rise out of them. They are insubstantial plants that can weave through a border and their repetition unifies a design but overdoing them can dilute the end result so don’t go crazy.
Verbena bonariensis
Foenciculum vulgare
Deschampsia cespitosa
Stipa gigantea
Thalictrum delavayi
Molinia caerulea ‘Transparent’
So once you’ve put the plants into categories how do you use them?
I suggest drawing up an edited wish list so that it includes 5 plants from each category and then make a note of their heights and flowering season next to each one. You should draw up separate lists for sun and partial shade and choose plants that have similar soil requirements. Once you’ve got to grips with these plants and experimented with different combinations you can fine tune the list and it could last you for your entire career.
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