Plant These Four Flower Bulbs and Tubers in March for a Gap-Free Summer Garden

Between the end of the daffodil season and the start of the roses, many gardens are left with a bleak gap – entirely unnecessarily, say gardening professionals.

Anyone planting the right flower bulbs and tubers now, in March, can ensure a bed that remains in bloom from June into autumn. Miss this opportunity and you may be looking at bare beds until July. Four species are crucial: they complement one another perfectly and fill the dreaded late-spring “colour gap”.

Why March determines summer flower displays

The spring sequence is usually the same: snowdrops first, followed by crocuses, tulips and daffodils – then, suddenly, there is nothing. Perennials are not ready yet, roses are only just getting going, and many annual summer flowers are still tiny.

“If you do not plant summer tubers until late April or May, flowering is often pushed back into high summer – leaving the early garden bare.”

March provides the ideal window. The soil is thawing, severe frosts have generally eased, and plants can begin growing gradually. This is exactly when summer tubers should go into the ground. They can establish roots in time, send up shoots early and flower from June, rather than only in mid-July.

The four key plants for a summer of uninterrupted flowers

Garden experts recommend combining four groups that cover different heights, flowering periods and growing positions:

• Dahlias for richly coloured beds
• Begonias for shade and partial shade
• Lilies for height, fragrance and structure
• Peonies as a long-term investment for the spring garden

Dahlias: an explosion of colour from June to October

Dahlias rank among the most popular summer-flowering plants, for good reason. They range from tiny pom-poms to enormous flower balls, in almost every colour except pure blue. Given the right start, they flower continuously from early summer until the first hard frost.

To achieve early flowers, it is not enough simply to put the tubers in the bed in April. Start them under cover in March instead:

• Place the tubers in pots filled with loose, relatively nutrient-poor compost
• Cover the tubers with only a light layer of compost
• Keep them somewhere bright but frost-free, such as an unheated conservatory or a garage with a window
• Maintain slight moisture, while avoiding waterlogging

Once night frosts are no longer expected outdoors, move the started plants into beds or large containers. Many varieties will then flower as early as June, directly following the final tulips.

Begonias: the quiet queens of shady spots

While numerous summer flowers shine in full sun, north-facing balconies and spaces beneath trees can often look rather sparse. This is precisely where begonias excel. They manage with little direct light and flower reliably throughout the summer.

For a successful start in March:

• Set tubers in trays or pots with the rounded side down and the slightly hollow side facing upwards
• Plant in loose, humus-rich compost and cover only thinly
• Keep them bright, frost-free and evenly moist

Begonias tolerate gentle sunshine, but thrive best in partial shade and shade. Water them regularly and prevent waterlogging during extended wet spells, and they will reward balconies or patios with an almost uninterrupted carpet of flowers.

Lilies: fragrant pillars in the flower bed

Lilies add structure to a border. Their tall stems and striking flowers act as natural pillars within the garden scene. Many varieties are strongly scented, making them particularly suitable along a patio edge or near seating areas.

Plant the bulbs outdoors in March, as soon as the soil can be worked:

• Planting depth: around two to three times the height of the bulb
• Position: sun to partial shade
• Soil: loose, deep and, above all, well drained

Some varieties flower in late spring, while others do not bloom until high summer. A skilful combination ensures there are always lilies somewhere in the garden, leaving few flower-poor periods between other perennials.

Peonies in March: a gift to tomorrow’s garden

Peonies are not for impatient gardeners, but they reward anyone willing to plan ahead. Once established in the right position, they can remain there for decades and become more abundant each year.

Planting them in March will not usually produce an immediate spectacular display. It is normal for a newly planted perennial to need two to three years before it really gets going. In return, peonies offer huge, often scented blooms that perfectly mark the transition from late spring to early summer.

What matters when planting:

• Do not plant too deeply – the tuber’s “eyes” should sit only around 3–5 cm below the soil surface
• Choose a site with good soil and as little competition as possible from shallow-rooted shrubs
• At least half a day of sun encourages flowering

“Anyone planting peonies in March is creating a faithful flowering treasure for many years to come – even if it is still modest this year.”

How to fill the flowering gap between spring and summer

The key is thoughtful succession planting. The aim is a bed in which spring favourites, summer tubers and perennials take over from one another without an obvious break.

One possible layout for a sunny bed:

• Front: small dahlias and lower-growing begonias
• Middle: taller dahlias and medium-height lilies
• Back: tall lilies and several peonies as permanent structural plants

Annual summer flowers such as zinnias or cosmos can be sown between them, adding further colour from high summer onwards. This keeps the bed lively from March to October, rather than letting it collapse after the spring display.

Common March mistakes – and how to avoid them

Many amateur gardeners plant enthusiastically but lose potential through small errors. Common problems include:

• Soil that is too heavy and wet, without drainage – tubers rot easily
• Bulbs and tubers planted too deeply
• The wrong position: lilies in full shade or begonias in fierce midday sun
• Feeding too early and too heavily, before roots have formed

A simple rule of thumb is: roots first, feed later. Initially, a little compost in the planting hole is enough. Apply mineral fertiliser later, once growth is properly under way.

What terms such as “tuber” and “bulb” mean in everyday gardening

Many people use these terms interchangeably. It makes little difference to day-to-day care, but this brief guide is useful:

For amateur gardeners, the key point is ultimately this: store them dry, avoid waterlogging when planting, and do not push them into icy, wet soil.

More flowers, less work: the long-term effect

Starting with dahlias, begonias, lilies and peonies in March reduces stress later in the season. The beds are already full, the basic framework is in place, and May becomes a matter of finishing touches with annual flowers or herbs.

There is an ecological benefit as well as an ornamental one. Continuous flowering supports bees, bumblebees and butterflies. Rather than a garden offering nothing once the tulips are over, it becomes a “buffet” from spring to autumn, with nectar and pollen at several levels and heights.

If you are unsure, begin on a small scale: a planter of begonias in the shade, a large pot of dahlias in the sun, a few lily bulbs in a perennial bed and a peony at a sunny edge. These four planting tasks in March often determine whether the garden shines in early summer or looks empty for weeks.