Why a native border is easier than it looks

The hardest work in any border happens in the first season. After that, a well-chosen planting of British natives and long-naturalised perennials will more or less look after itself, even if you only get out there with a watering can at weekends. Native plants have evolved alongside our rainfall, our soil and our insects, so they rarely sulk through a dry July or a sodden March the way a tender bedding plant will.

The trick is to choose plants that knit together into a dense mat. Bare soil dries out and fills with weeds; covered soil stays cool, holds moisture and shelters the beetles, frogs and ground beetles that deal with pests for you. Combine hardy geraniums, geums and asters and you get a border that flowers from May to October, feeds pollinators throughout, and asks almost nothing beyond an annual tidy-up.

Hardy geraniums: the backbone of the border

If you plant nothing else, plant cranesbills. They are tough, drought-tolerant once settled and generous with flowers, and several are genuinely native.

• Geranium sanguineum (bloody cranesbill) is native to limestone and coastal turf. Low, sprawling and covered in magenta or white flowers from June, with foliage that turns crimson in autumn.
• Geranium pratense (meadow cranesbill) is the taller native of damp meadows, with violet-blue flowers in early summer. The double forms look wonderful but single flowers feed far more bees.
• Geranium macrorrhizum is the plant for dry shade under trees, forming weed-smothering carpets with pink flowers in late spring and aromatic leaves that scent the whole border when brushed.

Space them 40–50cm apart and they will close ranks within two seasons. The clumps are long-lived; simply lift and split them with a spade every four or five years if the centres begin to die out.

Geums for early colour and damp corners

Geums bridge the gap between the last of the spring bulbs and the first of the summer perennials, and their semi-evergreen rosettes look good right through to November. They are happiest in soil that stays reasonably moist, so they suit the heavier soils many British gardens sit on.

• Geum rivale (water avens) is native to damp meadows and stream banks, with nodding, dusky apricot flowers. Plant it where the ground never quite dries out.
• Geum urbanum (wood avens) is the shade-tolerant native, with small yellow flowers and seed heads like little burrs that cling to your socks — a small price for greenery in dark corners.
• Garden forms in burnt orange and soft yellow bring stronger colour and repeat-flower if you deadhead them after the first flush.

Geums are short-lived compared with geraniums — three to five years is typical — so let a few seedlings settle or divide clumps in early autumn to keep the stock going.

Asters for autumn and bees

By September, most borders are running out of steam. Asters are not. Michaelmas daisies and their relatives open in late summer and carry on until the first hard frost, and their open, daisy-like flowers are one of the best late sources of nectar for bees, hoverflies and butterflies.

• Aster novi-belgii types are the classic tall border asters. Pinch the growing tips in late May — the "Chelsea chop" — to keep them bushy and reduce the need for staking.
• Aster divaricatus (white wood aster) thrives in dry shade beneath trees and produces clouds of small white flowers on near-black stems.
• Aster x frikartii is one of the longest-flowering of all perennials, often starting in July and continuing for three months or more.

Asters do suffer from powdery mildew if they dry out at the roots. A mulch and a good soak in a dry August will prevent it without any spraying.

Planting and soil preparation

Do the groundwork properly once and you will not need to water much again. Clear perennial weeds — especially couch grass and ground elder — before planting, because you will never get them out from between established clumps.

• Fork the top 20–25cm and work in two or three bucketfuls of garden compost or leafmould per square metre.
• Plant in autumn or early spring, when the soil is warm and moist but not frozen.
• Set geraniums and asters 40–50cm apart, geums closer at 30cm, and water each plant in well.
• Mulch the whole border with 5–8cm of compost or bark, keeping it clear of the stems.

Looking after the border through the year

For the first summer, water deeply once a week in dry spells — a thorough soak is far better than a daily sprinkle. After that, most established plantings in a normal British year need nothing at all.

In late February or early March, cut the whole border back to about 10cm, leaving some hollow stems standing for overwintering insects. Leave seed heads on the asters through the winter and the goldfinches will find them. Divide overcrowded clumps every few years, top up the mulch each spring, and resist the urge to tidy too thoroughly — the leaf litter and hollow stems are habitat, not mess.

Feed nothing, spray nothing, and you will still have a border full of bees from May to October.