Start with the Shape, Not the Shopping List

A relaxed cottage border begins with generous proportions. Give it at least 1.2 metres of depth, ideally 1.5, so plants can be layered front to back rather than lined up like soldiers. A gently curved front edge looks softer than a ruler-straight line and makes mowing simpler. If you have a fence or hedge behind, so much the better — it gives tall plants something to lean into.

Before you buy a single pot, fork 5cm of garden compost or well-rotted manure into the top 20cm and leave it. Resist the urge to feed heavily. Rich soil grows soft, floppy stems that need staking by July, which is the opposite of relaxed. Cottage planting is really about abundance on modest rations.

Plant in drifts of three, five or seven rather than ones and twos, and repeat the same plant two or three times along the border. That repetition is what makes a jumble look intentional rather than accidental.

The Spring Layer: Bulbs and Quiet Perennials

Spring is carried by bulbs. Plant daffodils and tulips in October at roughly three times their own depth, tucked between perennials so the yellowing foliage is hidden as the border fills out. Tulips are best treated as annuals in heavy soil — buy fresh each autumn and plant deeply, about 20cm down, to discourage them from splitting.

Underneath, use foliage plants that earn their space for months. Pulmonaria gives spotted leaves and early blue flowers, brunnera brings forget-me-not blue sprays and heart-shaped silver foliage, and epimedium and hardy geraniums such as Geranium phaeum knit the ground together. Forget-me-nots will self-seed everywhere given half a chance; pull handfuls out after flowering and leave the rest, because a little wandering is exactly what you want.

Early Summer: Foxgloves, Lavender and Height

Foxgloves are the signature plant of this style. They are biennial, so let a few flower and set seed each year, and keep a small nursery patch behind the border to raise replacements. Sow seed in June, plant out in September, and you will never be without them.

Lavender needs the opposite treatment: sun, sharp drainage and gritty soil. Mix horticultural grit into the planting hole, set the plant slightly proud on a small mound, and never cut back into old, leafless wood. Trim lightly after flowering, in August, taking off the flower stems and about 2cm of leaf.

Fill the middle with Nepeta, alchemilla, aquilegia and a peony or two. Catmint is worth three plants: shear it hard after the first flush and it will flower again in late summer. All of this needs little more than a tidy in July.

High Summer: Soft Grasses and a Loose Middle

Grasses are what stop a cottage border from looking like a herbaceous scuffle. Use Stipa tenuissima at the front for its blond, mobile tips, Deschampsia cespitosa for airy clouds, and Molinia or a smaller pennisetum further back. Plant them in threes, never singly, and aim for roughly one grass to every three flowering perennials.

Then let the daisies in: echinacea, scabiosa, achillea, helenium and the tall, see-through stems of Verbena bonariensis, which asks for nothing but light and self-seeds politely. Crocosmia and dahlias add late colour if you have room for their boldness. This is the moment to stop deadheading the foxgloves and let them brown off and scatter.

Carrying the Border into Autumn

Late colour is easy if you plan for it now. Asters, sedum, Japanese anemones and heleniums will take over from August, and their seedheads hold well into winter. Leave everything standing — eryngium, teasel, honesty and verbena heads feed birds and catch frost beautifully.

Cut back roughly half the border in October for tidiness, and leave the rest until early March, when you can pull the stems away in handfuls. Hollow stems left through winter are valuable shelter for insects. Top-dress with 5cm of compost in spring and let the worms do the digging; you should never need to fork over between established plants.

Keeping It Relaxed Rather Than Ragged

There is a difference between loose and neglected, and it comes down to a few hours a year. In late May, cut back asters and sedums by a third — the Chelsea chop — for shorter, later-flowering plants that need no staking. For anything taller, push hazel pea sticks in early, before the plants need them, and let the growth hide the supports.

Deadhead the lavender and nepeta after flowering, but leave seedheads on anything the birds enjoy. Lift and divide congested perennials every three years in spring or autumn, discarding the woody centre and replanting the vigorous outer pieces. Water thoroughly once a week in the first summer and in any prolonged dry spell, and mulch after planting to hold the moisture in.

Do that, and the border will look after itself for most of the year — which is the whole point.