Start with the light and the bones

Small gardens are unforgiving in the best possible way. Every plant is visible, so every plant has to work harder than it would in a sprawling border. Before you buy a single pot, spend a week noticing what your plot actually does: which corner catches the morning sun, where the frost lingers, which fence is baked by early evening heat. A north-facing courtyard in Leeds and a sheltered south-facing yard in Bristol need entirely different plant lists, and no amount of good intentions will override that.

Next, decide on a simple shape. A tiny garden with a dozen different ideas quickly looks like a jumble sale. Choose two or three anchor points — a small tree or large shrub in a pot, a bench, a path — and let the planting wrap around them. This structure is what carries the garden through the flat months of January and February, when flowers are scarce and you are mostly looking at shapes.

Evergreens: the quiet backbone

Roughly a third of your planting should be evergreen. That might feel dull when you are standing in a garden centre in May, surrounded by peonies, but evergreens are what stop a small plot looking empty for four months of the year. They also give you a backdrop that makes everything else look deliberate rather than random.

Good choices for containers and tight borders include skimmia, which tolerates shade and offers red buds right through winter; sarcococca, whose almost invisible flowers scent a whole patio in January; and Viburnum tinus, which quietly flowers from late autumn into spring. For something with a bit more attitude, a clipped Ilex crenata or a small pittosporum works well in a pot and can be trimmed to keep its shape. Avoid anything that will outgrow the space in three years — read the eventual height on the label, not the height of the plant in front of you.

Spring bulbs: the cheapest colour you can buy

Bulbs are the single best value in a small garden. They take up almost no space, they come back year after year, and they fill the gap between winter and the first real flush of growth. In a compact plot, plant them in layers so the same square foot works three times over.

• Snowdrops and winter aconites at the very front, planted in the green if you can find them.
• Crocus and dwarf iris in the gaps between perennials, where they will flower before the foliage fills in.
• Narcissi in pots — choose shorter varieties such as 'Tête-à-Tête' so they do not flop over the edge.
• Tulips in containers, where you can lift and replace them each year without guilt.

If you rent, bulbs in pots are your friend. Nothing is dug into the ground, nothing is left behind, and you can take the whole display with you when you move.

Summer perennials that earn their keep

In a small space, a perennial has to offer more than one good week. Look for long flowering, good foliage, or ideally both. Geranium 'Rozanne' flowers from June until the first frost and weaves through everything around it. Salvia and verbena keep going well into autumn and are adored by bees. Hakonechloa, a Japanese forest grass, brings a soft green cascade to a pot or a shady edge, then turns buttery yellow in autumn.

Add one or two plants with strong foliage — a heuchera in deep burgundy, perhaps, or a fern for shade — to carry the border when nothing is in flower. Repeat the same two or three plants rather than collecting a bit of everything. Repetition is what makes a small garden feel designed rather than accidental.

Winter stems, bark and scent

This is where most small gardens fall flat, and it is the easiest thing to fix. Winter interest comes from stems, bark and scent rather than flowers, and it costs very little.

Cornus sanguinea 'Midwinter Fire' gives orange and red stems that glow in low sun; cut a third of the oldest stems to the ground each March to keep the colour strong. Salix alba 'Britzensis' offers fiery orange-red whips. Hellebores flower quietly from January, and winter-flowering jasmine will scent a whole corner on a mild day. Even a single potted birch with white bark earns its place, especially with a small uplighter tucked into the base of the pot.

Putting it together in a tiny plot

Once you have your four seasons covered, the trick is keeping it manageable. Small gardens need less watering, weeding and pruning than large ones, but they also dry out faster and heat up quickly in summer.

• Group pots together so they shade one another and you water one zone, not ten.
• Use the largest containers you can fit — small pots dry out in a day.
• Top-dress with gravel or bark to lock in moisture and suppress weeds.
• Keep a small watering can by the door; you will use it far more often than a hose.
• Take photos each month for a year. Patterns emerge quickly, and next spring you will know exactly where the gaps are.

Aim for roughly a third evergreen, a third bulbs and long-flowering perennials, and a third structure — pots, paths, a seat. That mix will give you something worth looking at in every month of the year, even in a plot the size of a postage stamp.