Peak planting time for shrubs and perennials is fast approaching, and early autumn is ideal for making changes to beds and borders, as you can easily remember, or even still see, where things haven’t worked, or where there are gaps that need filling with colour, foliage or form.
Follow a few simple design rules when choosing new plants, plant and water in well, then the inevitable autumn rains should ensure they settle in this year for a great show next season.
Of the three elements colour, foliage and form, perhaps the most important is form in planting design. I wrote a little about it here (love your greens blog) - specifically evergreen structure, and how it comes to the fore in winter, giving your garden architectural interest and permanent sculptural shapes. But plant form in general is all about the shape of a shrub, tree or perennial when in leaf, and it plays a much more important role in planting design than we realise at first glance. It has way more impact on the eventual look of a garden than, say, flower colour or leaf shape.
- There are heaps of variations on plant shape, although the main groups are rounded (Choisya, clipped yew or box), a soft, yet strong form that creates a sense of containment; use to create ‘full stops’ at the ends of borders or as focal points.
- Then there are the hummocks (hardy geraniums, alchemilla, hebes are good examples), which soften the edges of borders and link different plants within a composition.
- Columnar forms (Pyrus calleryana chanticleer, rock mountain juniper) are unusual and very striking, making visual exclamation marks; assertive focal point plants.
- Then there are the gently arching specimens that bring movement and energy: bamboos, some of the shrub roses, buddleias and, of course, grasses. All will need space to show off that lovely habit.
- Finally, the fan or spiky form – a tree like Prunus Kanzan, for instance (combine two for a lovely informal arch) or make use of them in small gardens as they give you plenty of planting space underneath. Smaller but equally dramatic fans include phormiums, ferns and irises.
A lovely combination of forms for late summer and early autumn is airy, swaying grasses such as Stipa tenuissima or Anemanthele lessoniana with rounded, flat-topped sedums. There’s soft colour there, too, fitting for the changing of the seasons.
Contrasting leaf and plant shape is pleasing to the eye; as seen with this euphorbia, pheasant grass and nasturtiums
Combine form with texture to artful effect and you’re on the road to some really good planting design. By texture, garden designers mean not so much the actual feel of a plant’s foliage but the visual sensation of rough or smooth that it gives. So think coarse, medium or fine textured plants, which roughly correspond to those with large, medium and small leaves; combining the three textures in planting groups is always a winner – it’s visually interesting, arresting and pleasing.
When I studied planting design at Capel Manor College, we’d spend long summer evenings sketching in Regents Park, assigned with picking out groups of plants that illustrate successful combinations of form and texture. Phormium tenax sprouting tall and spiky behind a group of gently rounded clipped box balls, both set against a bold bank of glossy-leaved Prunus laurocerasus ‘Otto Luyken’, for example.
I found myself doing the same plant-spotting the other day in the gardens at Eltham Palace. Strap-like leaves of agapanthus below the large shiny foliage of a camellia, underplanted with hardy geraniums. There is a little colour from the fading agapanthus flowers, but the success of the arrangement is all about leaf texture and plant form.
Agapanthus and Camellia
Then there was butcher’s broom (Ruscus aculeatus), the foliage feathery and fine, with the large glossy scoops of bergenia leaves – a brilliant combination for a shady area.
Ruscus and bergenia
Another was a sublime ground cover combination of deciduous ferns with the tight evergreen rosettes of pachysandra terminalis, then right at ground level the tiny heart-shaped, plum-tinged foliage of purple-leaf violets. I’m definitely going to recreate this in the shady border underneath my acer at home.
Pachysandra, fern and violets
It’s not easy, I know, but try not to be swayed too much by flower colour when choosing the next inhabitants of your beds and borders. Look instead at the shape of the plant and the texture of its foliage, combine these things with a little thought, and you’ll be surprised at how pleasing the effect can be.
Happy autumn planting!
Francesca Clarke, Journalist and Garden Designer