Perennial gardens take their cues from nature; they’re sprawling, wild and diverse — a botanical wonderland in every season.

A famous urban example is the New York City High Line — the rail trail designed by one of the leaders of the New Perennial movement, Dutch garden designer Piet Oudolf. While the trend originated in Europe, in recent years it has gained popularity in Australia too.

Victorian garden designer Tim Pilgrim of TP Gardens (who has been championing the trend in his naturalistic cottage-style gardens across his 15 year-career), explains, ‘It’s about taking cues from your wider landscape and bringing it into the picture where you can, blending the garden to it, and giving the garden a sense of place, Tim says. ‘I love the ever-changing nature of perennials, especially the way they change through the seasons and stand into decay, revealing their true charm and character.’

Below, Tim, fellow landscape designer Ralph Bristow and co-owner of Antique Perennials (a perennial nursery in Kinglake, regional Victoria) Mike Morant — break down the New Perennial movement and share their tips for planting.

What is the New Perennial movement?

The New Perennial movement, or ‘Dutch Wave’, is a naturalistic, plant-driven design that mimics or takes inspiration from nature. These gardens embrace perennial plants, which live for more than two years (some can live up to hundreds!). While herbaceous perennials die back annually over winter (their roots and crowns survive underground and re-shoot in spring without needing to be replanted), other perennials might last all-year round.

‘This style of planting design began in Holland and Germany, led by plants people like Mien Ruys, Karl Foerster and Henk Geretsen in the ‘70s and ‘80s. But it was really made famous by the Dutch garden designer Piet Oudolf who has brought this style of garden design to the world stage,’ Tim Pilgrim says.

Mike Morant and Matt Reed have been bringing perennial plants to Australia for more than two decades in their nursery, after being ‘tired of seeing the same few plants on repeat available at retail nurseries.’

‘This movement has probably been birthed from a move away from the stuffy border and regimented formal gardens of yesteryear. For me, the more naturalistic, casual planting style of perennials lends itself to comfortable and relaxing spaces,’ Mike adds.

What are the key features of a perennial garden?

You can pick a perennial garden by its large drifts, repetition, and sporadic placement of herbaceous perennials and grasses. ‘There is also a preference for letting the seasons of nature take their course and not intervening or tidying up as much as you would in a less “wild” style of garden,’ Tim notes.

Perennial gardens tend to be very layered with a mix of plants, grasses, and flowers in differing heights, textures and colours that give the garden a rambling and dynamic appearance. But the key is that everything has been planted thoughtfully, designed to evolve with the seasons. ‘You can use plants that are growing, flowering, decaying at different times of the year so there is something happening at all times,’ Ralph adds.

Are perennial gardens easy to establish? What are the benefits?

Because of the nature of the plants, Tim says perennial gardens are actually quite easy to establish and you can usually expect a full display in the first year of planting — unlike trees, climbers and shrubs which can take longer to establish. ‘Most perennials and grasses don’t like overly rich soil with too many amendments or fertilisers but prefer open free draining soils,’ he explains.

Artist and landscape designer Ralph Bristow agrees there are many advantages to perennial gardens, including ‘only having to plant once in a season, as many perennials keep going year after year; soil health; value for money – plants can be propagated by division, cuttings, and seed with basic skills; there is a plant that can be used for almost any situation or style of garden,’ he adds.

‘Every season is celebrated and embraced,’ Ralph explains. ‘This also extends into the winter when the herbaceous perennial’s growing period ceases, and they move into a dormant state. Another reason I love designing with perennials is because of the insects and wildlife that thrive in these types of ecosystems.’

What plants can be used in perennial gardens here in Australia? 

Tim explains there aren’t many of native perennials here in Australia because the style evolved overseas. ‘But there are plenty from the northern hemisphere that work well in our modern Australian context,’ he adds.

‘I think that you always have to be sympathetic to your site and surroundings. It doesn’t need to be 100 percent native but it has to work within its context.’

He says structural grasses that offer great movement in the breeze are great at helping seamlessly blend perennial gardens into to the outer landscape. ‘Some of my favourites are Calamagrostis (‘Karl Foerster’), Miscanthus, (silvergrass), Pennisetums and Panicums,’ he says.

Mike recomends Stipa Gigantea as another great grass that works in all perennial gardens. ‘It begins to flower and gives welcome height in late October/early November, when most perennials are playing catch-up. These flowers then last right through to late autumn. It’s a super tough grass that enjoys Australian conditions,’ he says.

Herbaceous perennials like Eupatoriums and Achilleas (Yarrow) offer great pops of clustered pink flowers, and Salvia, Echinacea (Purple Coneflower) and Verbenas are all examples of perennials plants with strong seed heads that change from coloured flowers to rusty straws, brown foliage, and black defoliated stems across the year. There’s also plenty of vertical plants like Veronicastrum (Culver’s Root) and Veronica that can bring an additional sense of height to your planting scheme. The list goes on!

What are the rules for creating a perennial garden?

• Plant in odd numbers. ‘Three or more depending on the size of your garden space is good,’ Tim says.
• No more than 30 percent of the garden should be filled with grasses.
• Don’t be too uniform. ‘Be sporadic with your placement just like nature is repetition, I like to repeat planting groups in the garden so that they draw your eye through the scene,’ Tim adds.
• Plant on the ‘shoulder seasons’, which is early spring and autumn when there is some warmth and moisture in your soil.
• Be careful not to turn your garden into a ‘plant museum’, collecting one of everything. ‘Less can certainly be more, try to be restrained,’ Mike says.
• Don’t get too hung up on specific colours. ‘Height, form and texture are far more important,’ Mike adds.
• Do your research to determine what plants belong where. ‘Get to know your plot – soil, rainfall, slopes, wet spots, dry spots and general climate.’
• Pay attention to how the garden changes over time, and adapt. ‘If something isn’t working and needs changing you can edit the garden and move things around in winter,’ Ralph says.
• It may be advantageous to sketch up a plan, but be flexible, be bold and do what you want to do!