Creating a Low-Maintenance Border with Hardy Perennials

Why Hardy Perennials Earn Their Keep

A border planted with hardy perennials is one of the great bargains of British gardening. These are plants that die back to the ground in autumn, sit quietly through the frosts, and then push up fresh growth the following spring without any help from you. Once they are settled, most will bulk up year on year, and many can be lifted and divided to fill gaps elsewhere for free.

The trick is to choose plants that suit your soil and your patience. A border stuffed with choice rarities that need staking, watering and cosseting will soon become a chore. A border built around tough, proven varieties will look after itself from May to October and still give you something to enjoy in the depths of winter.

Pick Plants That Do the Work for You

Reliability matters more than novelty. The following performers will shrug off most of what a British season throws at them, provided they are not sitting in a puddle.

• Hardy geraniums such as Geranium 'Rozanne' and G. macrorrhizum, which knit together to smother weeds and flower for months.
• Alchemilla mollis for frothy lime-green flowers that seed gently about without ever taking over.
• Nepeta 'Six Hills Giant' and Salvia nemorosa 'Caradonna' for spires of blue that draw in bees from June onwards.
• Hylotelephium (the old sedums) for flat heads of pink that turn bronze and stand through winter for the frost to catch.
• Achillea, echinacea and rudbeckia for late colour that lasts well into September.
• Epimedium and brunnera for the shady end of the border, where little else will grow.

Notice how many of these are drought-tolerant once established. That is no accident. If you choose plants adapted to dry summers, you can go away for a fortnight in July without coming home to a scene of collapse.

Sort Out Drainage Before You Plant a Thing

Winter wet kills more perennials in Britain than cold ever does. Most of the plants above will survive a hard frost, but none of them enjoys roots sitting in soggy clay from November to March.

If your soil is heavy, fork in plenty of well-rotted organic matter and a good barrowful of horticultural grit across the whole planting area, not just in the planting holes. On genuinely waterlogged ground, plant into a slightly raised mound of improved soil so that water drains away from the crown. On very light, sandy soils the opposite applies: dig in leafmould or compost to hold moisture through dry spells.

Plant in autumn or early spring, when the soil is warm and damp but not frozen. Water each plant in well, and keep an eye on them through their first summer. After that, most will fend for themselves.

Plant in Drifts, Not Dots

One of each variety scattered along a border rarely looks generous, and it makes weeding fiddly. Group three, five or seven of the same plant together and let them merge into a soft patch of colour. Repeating those patches two or three times along the border pulls the whole scheme together.

As a rough guide, allow a metre or so between the larger grasses and tall perennials, and 30 to 45 centimetres for the front-of-border plants. They will close ranks within two seasons, and the dense canopy of leaves is your best weed suppressant.

Mulch Well and Water Less

If you do one job that pays you back all year, make it mulching. In early spring, once the soil has warmed and the new shoots are showing, spread a generous layer of well-rotted manure, garden compost or leafmould over the border. Aim for five to seven centimetres deep, and keep it clear of crowns and stems so nothing rots.

A good mulch does three things at once: it feeds the soil slowly, it holds moisture in during summer, and it stops annual weed seeds from germinating. Hoe off any that do appear on a dry, sunny morning while they are still tiny. For Mediterranean plants such as lavender or thyme, use gravel or grit instead of compost, which suits their preference for lean, sharp drainage.

Watering should be a first-year job only. When you do water, give plants a thorough soak rather than a daily sprinkle, and always aim at the soil rather than the leaves. Deep watering encourages roots to travel downwards, which is exactly what you want.

Keep the Tidy-Up Quick and Rough

Resist the urge to cut everything down in October. Seed heads and grasses left standing feed the birds and look marvellous in low winter sun. The RHS and wildlife charities both suggest leaving the border until late February or March, when you can cut it back in one morning and compost the lot.

In late May, try the Chelsea chop: pinch out the growing tips of taller perennials such as sedum, asters and achillea. They will bush out, flower a little later, and need no staking. Divide congested clumps every three or four years in autumn or spring, replanting the healthy outer pieces and giving the rest to a neighbour.

That is the whole routine: a spring mulch, a May pinch, a late-winter cut, and the occasional split. Do that and your border will return, year after year, with less work each season rather than more.