Why bulbs and perennials work so well together

The trouble with spring bulbs is never the flowers — it is what follows them. A daffodil needs roughly six weeks of green leaf after blooming to store enough energy for next year, and during that time the border can look tired and straggly just as everything else is waking up. Plant perennials directly above and around your bulbs, however, and the problem solves itself. The perennial shoots rise through the yellowing foliage, hiding it neatly, and by the time the bulb leaves can be cleared away the border is full of fresh growth.

This simple piece of layering — bulbs below, herbaceous perennials above — buys you colour from February right through to August in the same patch of ground. It also makes better use of space in a small garden, keeps weeds down, and means you are not staring at bare soil for half the year.

Matching partners by flowering time

The trick is to think about the six weeks after flowering, not the flowers themselves. Work out when your bulbs finish and choose perennials that bulk up at exactly that moment.

• Early bulbs — snowdrops, crocus, dwarf iris. Their foliage has usually gone by mid-April, so pair them with early risers such as pulmonaria, brunnera and epimedium, which cover the ground while the bulbs are still in flower.
• Mid-season bulbs — daffodils, hyacinths, snake's head fritillary. Foliage lingers into late May or June. Choose perennials that emerge strongly in May: hardy geraniums, alchemilla, nepeta, hostas and paeonies are all reliable.
• Late bulbs — tulips, alliums, camassia. Leaves can hang about until July. Set them among achillea, salvia nemorosa, echinacea, helenium and asters, which are filling out just as the bulb foliage flops.

As a rule of thumb, the perennial should reach roughly the height of the bulb foliage it is hiding. A clump of alchemilla will mask a modest narcissus beautifully; it will not disguise a tall tulip, so choose taller companions for those.

How to plant the layers properly

Autumn is the moment to put bulbs in, and it pays to plant your perennials first, or at least to mark their positions with short canes so you know where the crowns sit.

• Fork the bed over and work in a couple of handfuls of grit per square metre if your soil is heavy. Bulbs rot in waterlogged ground, and perennial crowns dislike sitting wet over winter.
• Plant bulbs at the correct depth: roughly three times their own height of soil above the nose. That means about 15cm for daffodils, 20cm for large tulips, 10cm for alliums and 8cm for small bulbs such as crocus.
• Keep bulbs at least 10–15cm away from established perennial crowns. Use a long-handled bulb planter rather than a spade so you are less likely to spear roots.
• Water the area in well and label the clumps. A few inconspicuous canes now will save you digging into dormant crowns next autumn.

In containers the same principle applies in miniature. Fill the bottom third with gritty compost, set the bulbs on top, cover with more compost, then plant shallow-rooted perennials above and finish with a gravel mulch.

A border plan that runs from March to August

Along three metres of sunny border, try this sequence. In the front, snowdrops and crocus naturalised beneath pulmonaria and epimedium carry you through March. Behind them, narcissus 'Thalia' rises through clumps of alchemilla and hardy geranium, whose soft mounds close over the daffodil leaves by early June.

Next, tulip 'Ballerina' threaded through nepeta and salvia nemorosa gives you late spring fire, with the grey-green nepeta foliage stepping in as the tulip petals drop. Allium 'Purple Sensation' then sends its globes up through the same planting in early summer, with achillea opening beneath it.

Come July, the perennials take over entirely: echinacea, helenium and asters, with sedum heads turning pink into September. Not a bare patch in sight, and no lift-and-store routine for the bulbs.

Looking after the layers through the year

The main discipline is patience with bulb foliage. Never tie it in knots, braid it or cut it back while it is still green — the plant is feeding next year's flower. Wait until it has turned straw-yellow and pulls away easily, by which point your perennials should have covered it anyway.

• Deadhead spent bulb flowers so energy goes into the bulb rather than seed, but leave the stems.
• Give a high-potash liquid feed — a tomato feed is ideal — as the flowers fade, watering it over the bulb foliage.
• Leave perennial stems standing over winter for seedheads and insect shelter, then cut back in early spring. This also protects emerging bulb tips from hard frost.
• Lift and divide congested perennials in autumn or early spring, replanting offsets away from your bulb clumps.
• Watch for slugs on hostas and young perennial shoots in damp springs.

Small gardens, big payoff

If space is tight, layering is the single most useful trick you can adopt. One square metre can hold crocus, a clump of hardy geranium, a late tulip and a salvia, giving you flowers for five months from ground you would otherwise leave empty. Even a narrow front border or a pair of large pots will reward you richly. Choose two or three combinations, plant them generously, and let the seasons stack up on top of one another.