Pic 1: Piet Oudolf’s planting at Scampston Hall Gardens, UK. (photo Nick Robinson)
Europe and North America are ‘ablaze’ with a wave of colourful, pollinator friendly perennial planting. The work of designers like Piet Oudolf, Tom Stuart Smith, Sarah Price, James Hitchmough and Nigel Dunnet has brought big scale planting with herbaceous perennials into two very important areas: the low maintenance landscape and the wildlife landscape.
It’s true: perennials are no longer to be associated with tedious staking and dead heading, annual lifting and dividing, manuring, and constant weeding. And yes, these stunning visual feasts are also a paradise for pollinators and other desirable wildlife. Perennial planting, in diverse colourful meadows and masses, now embraces natural form and seasonal cycles of growth and decay with seed heads and winter appearance very much part of the attraction.
Dutch plantsman Piet Oudolf became very successful thanks to his bold and unusual use of colour and winter effects. He started his career as a plant nurseryman, and his arrangement of plants echoes the intensity and boldness of plants laid out in nursery stock beds – large sweeps of texture and colour. His clumps and drifts of plants typically include robust perennials plus the careful use of grasses to counterpoint the vibrant flower colours and sculptural forms. Oudolf helped to popularize a new range of robust herbaceous plants and grasses that offered these qualities.
Pic 2: Piet Oudolf’s planting drifts displaying his characteristic colours at Trentham Gardens, UK. (photo Nick Robinson)
But new perennial design in not just about which fashionable plants to use – what marks it out it is knowing the ecology that lies behind the horticulture – what naturally grows well with what: how to create lasting, balanced combinations or, as I prefer to call them, plant ensembles. These are also designed to be rich garden habitat, attractive to wildlife, particularly pollinating insects.
Pic 3: James Hitchmough’s layered meadow mixture at Oxford Botalical Garden, UK. (photo Nick Robinson)
Recent developments have focused on ecologically based mixes of perennials by James Hitchmough and, in the case of Nigel Dunnett’s work – also annuals, both forming a meadow type planting. These mixtures are designed to perform through much of the year with interest refreshed as each new layer of foliage and flower emerges through the previous one. As gardener Thomas Rainer remarked:
“I began to think about plant composition differently. Before, I always understood one plant as inhabiting one place. But this new succession approach meant that multiple plants can inhabit the same space; they just emerge at different times. Some plants last, while others disappear entirely.”
For me, this seasonal emergence and layering is the key to getting the most value from planting. Even in the northern parts of New Zealand where the seasons are less marked there is a vibrant sequence of flower, foliage and fruit colour through the year. This can be artfully employed in planting design – winter bulbs like scented Narcissus, South African spring bulbs, summer emergents followed by autumn flowers like asters some of which, such as red hot pokers – Kniphofia, flower well into winter. With care, all these can dwell in the same patch of ground, the foliage and flowers on one disappearing or reducing as those of the next emerge.
Pic 4: An ensemble of summer perennials by Nick Robinson at Pakuranga, Auckland. Agapanthus inapertus, Phlomis russeliana, Libertia cranwelliae, Dietes bicolor and Rudbeckia fulgida (photo Nick Robinson)
One successful and simple example of this which I have used successfully on a number of occasions is the combination of bugle – Ajuga ‘Jungle Beauty’ for foliage at ground level and spring flower, merging (non-invasive) Agapanthus and Liriope for summer flower, and kaffir lily – Schizostylis coccinea (now called Hesperantha coccinea) for autumn and winter colour. These four species grow very happily together, occupying complimentary niches in space and time – try it!.
This kind of plant knowledge takes a while to acquire but leads to very satisfying and easy to maintain results because there is so little opportunity for weeds to get established. It means we can use perennials with confidence over larger areas (the diversity is in the mix and the seasonal succession) and we can get multiple values from small bits of garden in small urban spaces.