Plant These Four Flowers in March to Close the Garden’s Flowering Gap

If you find yourself staring in spring at faded flowerbeds and empty containers, you are far from alone. Once spring-flowering plants have made their grand appearance, many gardens are left with a colourless gap before roses, perennials and summer flowers take over. A little planning in March can shorten this lean spell considerably, keeping the garden in bloom without interruption.

Why March matters so much for gardeners

During March, the soil gradually warms up and severe frosts ease in most areas. This is the period that determines whether the garden is already glowing in early summer or remains rather sparse until July.

“If you plant summer-flowering bulbs and tubers too late, you delay the entire flowering period – and lose weeks of colour.”

Experts generally advise planting summer bulbs and tubers between early March and mid-May. March offers the greatest advantage: plants have time to establish their roots, begin growing sooner and reward you with a noticeably earlier start to flowering.

If you wait until late April or even May, much of the garden falls behind. After the daffodils and tulips have faded, beds, borders and containers may stay green for a long time but offer few flowers. Four carefully chosen plants can tackle this issue: dahlias, begonias, lilies and peonies.

Dahlias: bursts of colour from June into autumn

Dahlias are among the most valuable summer tubers for a long, abundant flowering display. Originating in warm climates, they dislike sitting in soil that is both wet and cold. Rather than being sown like marigolds, they should be started early in protected conditions.

How to get dahlias growing in March

In March, dahlia tubers are best kept out of open ground initially and started under cover in pots or crates:

• Fill a large pot with loose, humus-rich compost.
• Position the dahlia tuber with its “neck” facing slightly upwards.
• Cover it with only a light layer of compost, water well but do not saturate it.
• Place it somewhere bright and frost-free, such as an unheated conservatory or greenhouse.

This encourages the eyes on the tuber to shoot as early as March. Young plants can establish themselves in this protected setting before being moved into beds or large containers from May, once frost is no longer a risk. Gardeners who use this method can often enjoy the first flowers in June, with blooms continuing into October.

Dahlias are available in countless forms, including ball-shaped flowers, star-like varieties, cactus types and single blooms with visible centres. They suit both cottage gardens and modern, minimalist schemes. Choose a sunny or partly shaded position and water regularly. The tubers do not tolerate waterlogging well.

Begonias: a solution for shaded balconies and north-facing areas

While dahlias thrive in sunshine, begonias perform best in partial shade and shaded spots. They allow even north-facing balconies and darker corners of the garden to be filled with colour.

Starting begonias in March

Begonias are also sold as tubers. Ideally, start them in trays or pots during March:

• Fill a shallow tray or pot with light, relatively fine compost.
• Lay begonia tubers with the hollow side facing upwards.
• Dust them with only a very light covering of compost; do not bury them deeply.
• Keep them moist but never wet, in a bright, frost-free place.

Once the first shoots emerge, the plants soon begin to put on foliage and bulk rapidly. By late spring, they can be moved into window boxes, hanging baskets or slightly sheltered beds.

With suitable care, begonias flower almost continuously throughout the summer. Regularly removing spent blooms and watering moderately but consistently will produce a dense cloud of flowers. Another advantage is their ability to cope with gentle sun as well as fully shaded positions – a useful quality that few flowers offer.

Lilies: fragrant vertical features for flowerbeds

Lilies offer more than attractive flowers. Depending on the variety, they grow from 60 to 150 centimetres tall, creating vertical highlights among lower perennials and ground-covering plants. Their fragrance can fill entire patios, especially in the evening.

Planting lily bulbs in March

Lily bulbs can be planted directly outdoors in March, provided the ground is no longer subject to persistent frost. Well-drained soil is essential, as it prevents the bulbs from rotting.

“Plant lily bulbs at two to three times their own height – this keeps them stable and prevents them from drying out.”

Sunny beds or sites with light shade are suitable. Many varieties begin flowering in late spring, while others appear in high summer. Combining different types can bridge almost the entire period between the final spring flowers and the main perennial display.

A simple planting timetable can be useful:

Plant	Planting time	Possible start of flowering
Dahlia	March in a pot, into the bed from May	from June
Begonia	March in a pot, outdoors from May	from late May / June
Lily	March directly into the bed	from May, depending on variety
Peony	March (or autumn) into the bed	from the 2nd–3rd year after planting in spring

Peonies: plant now for abundant springs in the years ahead

Peonies will often not solve the immediate flowering gap in the current year. They are an investment for the future. Planting them in March prepares the garden for lavish spring displays in the years to come.

These perennials are regarded as exceptionally long-lived and robust. Once well rooted, they can remain in the same position for decades and improve with every passing year. However, many amateur gardeners underestimate how long a young plant needs before it truly gets going. A settling-in period of two to three years is normal before the plant is covered with its characteristic large, rounded blooms.

How to plant peonies correctly in March

Correct spacing and planting depth are crucial. On herbaceous peonies, the buds – known as “eyes” – should be covered by only a thin layer of soil. If the plant is set too deeply, it will flower much less well.

• Select a sunny site that is sheltered from wind where possible.
• Prepare loose, deep soil and remove stones and old root material.
• Set the plant so that its buds sit only a few centimetres below the surface.
• Water thoroughly and keep weeds at bay during the first few months.

The reward for a little patience is that peonies provide a reliable framework for the bed over many years, delivering an impressive late-spring display while other perennials are only just beginning to grow.

How these four key plants close the garden’s flowering gap

By combining dahlias, begonias, lilies and peonies thoughtfully, you can cover a wide flowering window. Spring bulbs such as tulips and daffodils provide the opening display. The first lilies and pre-started begonias then take over, followed a little later by dahlias in full force. In the following year, more established peonies add to the show and dominate the late spring.

“The art is to link spring, early summer and high summer so that not every bed is ever ‘resting’ at the same time.”

Conveniently, the four plant groups complement one another: begonias fill shaded gaps, dahlias and lilies favour sunshine, and peonies provide structure and permanence. Adding a few annual summer flowers, such as zinnias or cosmos, between them makes the flowering sequence almost unbroken.

Common mistakes when planting in March

Typical errors are easy to avoid:

• Keeping tubers and bulbs too wet, which can lead to rot.
• Planting peonies too deeply, resulting in weak flowering or no flowers at all.
• Being impatient by cutting back or moving plants before they have become established.
• Choosing the wrong location, such as placing dahlias in permanent shade or begonias in harsh midday sun.

Thinking ahead to summer while planting in March naturally encourages more careful planning. One simple tip is to insert a small label with the variety name and planting date as you plant. This makes it easier to keep track when only delicate shoots are visible in April and May.

Useful extra information for a carefully planned summer of flowers

The terms “tuber” and “bulb” are often used interchangeably in everyday language. From a gardening perspective, however, they describe different storage structures. Lilies have true bulbs made up of scales, whereas dahlias form tuberous root clusters. In practical terms, one point matters most: both types store nutrients and produce new spring growth from these reserves. Handling them carefully during planting protects these stores.

If space is limited, almost all of the plants mentioned can also be grown in containers. Use large pots with drainage holes and good-quality compost. A considered watering approach is particularly useful on balconies: saucers stop water from draining away immediately, but they should be emptied after heavy showers to avoid creating a “bathtub”.

Even a small terraced-house garden can be planted to create a surprisingly dense carpet of flowers. A narrow bed beside the patio containing peonies and lilies, a row of dahlias in front, and shade-tolerant begonias around the edges can make the grey gap after the spring display almost disappear. Starting now in March brings significantly more colour in the same year while also laying the foundation for many flower-filled seasons.