Summer success with Perennials

One of the chief lessons I learned as head gardener of The Diggers Club is how important it is to plan gardens for summer. Summer is the time when we want to live outdoors with our friends and family, eating and playing together.

But many of us unconsciously plant spring gardens. It’s a doddle to make a garden look good in spring. The weather is kind, and many plants flower during that season. Planting tulips, viburnums, wisterias and lilacs gives an easily-won burst of fluffy floral glory. But that glory is fleeting. ‘Spring’, as British gardeners know it, is non-existent in northern Australia and brief in southern states.

In Victoria, we get three weeks of mild weather before hot northerly winds turn the landscape brown in November, heralding the start of our five month-long summer. Many of the plants we have fallen in love with from British gardening books don't perform the same way in Australia as they do in Britain.

British gardens rarely suffer the heat stress ours are subject to for months each year, so spring-flowering plants often bloom over an extended period and remain green and lush throughout their brief summer. Here, things are different. It's unreasonable to expect spring plants to form the backbone of our garden during summer, so we need to look to a different plant palette.

To earn a place in my garden a plant has to ‘do its thing’, whether that be flowering, fruiting, autumn foliage or whatever, for at least a month. When not doing its thing, the plant must either contribute an interesting form to the design or fade politely into the background.

It must require only one or two interventions per year (say, cutting back in winter, and deadheading in summer), and only require sufficient watering to get it through the most brutal days of late summer. If it has more than one season of interest, it gets extra marks.

I want my front garden to look good all year around, so I've designed it to not be dependent on floral colour for its interest. Instead, it features interesting foliage, stems and forms. Three pencil pines (Cupressus sempervirens ‘Glauca’) staggered through the front garden give vertical rhythm to the design. Together with dark Escallonia ‘Iveyi’ hedges, the pencil pines frame the view of my house and tie it to the sharp lines of the architecture.
Rosa glauca, Cordyline australis ‘Purpurea’, Phormium ‘Annie’s Red’ and coppiced Cotinus ‘Grace’ give weight with their purple foliage. Too much purple foliage can tip the mood from ‘sombre’ to ‘depressing’, however, so I use lots of apple greens and greys to balance this — Phormium cookianum, Miscanthus transmorrisonensis, and Euphorbia rigida.

Fluffly grasses contrast with the stiff, sword-shaped foliage of Phormium and Beschorneria. The mounding forms of Euphorbia and Bupleurum fruticosum contrast with vertical pencil pines and Malus trilobata.

Perennials and ornamental grasses are the mainstay of my summer garden. Salvia, Agastache, Anthemis, Perovskia, Verbena and Sedum saturate the garden with the intense colours I love, and are constantly abuzz with bees, butterflies and honeyeaters. Miscanthus and Panicum grasses add texture with their graceful foliage and flower heads, lending a cooling atmosphere as they rustle in the breeze. The airy golden awns of the giant oat grass (Stipa gigantea) sparkle like gold dust hanging in midair.

There are several approaches to combining perennials. Traditionally, designers arranged them based on flower colour. I prefer the approach of the Dutch garden designer Piet Oudolf, who combines perennials based on their shapes and forms.

The chunky, cauliflower-like heads of Sedum contrast with crisply vertical Calamagrostis grass. Flat daisy heads of Anthemis and Gaillardia work well with hummocky Salvias and the airy seed heads of Panicum grasses, with the occasional clump of Kniphofia thrusting skyward. Once I have composed the shapes in my design, I add colour like a garnish that brings the design to life.

For me, combining colours is easy. I'm a more-is-more kind of gardener, so I file all colours under ‘YES’. From shocking blues to violent pinks and moody purples, screaming vermillion, cadmium yellow and tangerine, I love all the colours. It's enough to give the Pastel Police a heart attack.

I consider the whole of a plant when combining colours, not only its flower petals. For example, the flowers of Agastache aurantiaca are pale orange. But look closer. The bracts are mauve, the buds are mallow pink, and the foliage is blue-grey. This allows it to blend not only with hot colours, but with pastels, too. The only colour I exclude from my summer border is pure white. White can look too flat and harsh under the summer sun, and it's too aloof to play nicely with other colours. I keep white flowers and variegated foliage together in a lightly shaded part of my garden, against a background of dark, glossy foliage to absorb their brilliance. It looks especially beautiful in bright moonlight.

Just as my ornamental garden is looking its most colourful, my food garden is at its most abundant. The ‘Cambridge Rival’ strawberries are just finishing, cane fruits are in full swing, and gooseberries and black currants are ripe.

Like every gardener, I'm swamped with beans and zucchini in summer, just as I'm struggling to cope with the glut of Asian vegies and leafy greens I rashly over-sowed in spring. I'm up to my eyeballs in duck eggs, which become meringues and the richest ice cream ever; perfect for accompanying the surfeit of berries. The first batch of ducklings have grown fat and happy and are ready to go to ducky heaven (which, coincidentally, is in my freezer).

Summer is a wonderful time to garden. Choose the right ornamental plants and you can have a flowery, abundant garden even during the hottest, dustiest days. Redirect water savings made in your ornamental garden towards growing your own food. Perhaps the trickiest thing about gardening is clawing back time from the daily grind to spend in your garden. If you can find a way to do that, I guarantee you'll never regret it. Time spent in the garden is time well spent.