March gardening tip: This perennial will keep your flowerbed bright all summer long.

If your garden still feels bare right now, one single plant choice can change that in an instant - and keep it looking good all summer.

Anyone who picks up a spade in March can look forward to a vivid burst of flowers from June right through to autumn. The plant in question is phlox - a perennial that was dismissed for years as old-fashioned, but is now making a clear comeback in UK gardens thanks to its bright colours, strong fragrance and surprisingly modest upkeep.

Why phlox can save your summer display

Phlox has a fitting name: the word comes from Greek meaning “flame”, and that’s exactly the effect it creates in a border. Depending on the variety, flowers range from pure white and soft pastels to bold raspberry red, violet, and even bicolours with a contrasting eye or striped petals.

"Phlox turns an ordinary border into a blazing summer scene - with scent, colour and an astonishingly long flowering period."

Many gardeners still associate phlox with a traditional cottage garden. That very nostalgic character is a big reason it’s popular again today, particularly in naturalistic or rural-looking gardens. It sits beautifully alongside old roses, asters or coneflowers, and attracts bees, bumblebees and butterflies in large numbers.

March planting: how to make the most of the window for phlox

March is an excellent time to plant phlox - both perennial and annual types. The soil is starting to warm up, yet it still holds plenty of moisture. That gives plants time to root properly and head into the season with a strong start.

• Position: Sunny to lightly shaded; the more light it gets, the heavier the flowering.
• Soil: Loose, humus-rich, fertile and free-draining - but not bone-dry in summer.
• Spacing: 30–40 cm, so air can circulate around the leaves and fungal problems are less likely.
• Watering: Water thoroughly after planting; later on, top up regularly, especially during dry spells.

Planting in March sets you up for colour from June well into autumn - and depending on the variety, right up to the first frosts.

The stars of the border: tall phlox varieties

The best-known phlox are the taller, perennial forms. They can reach up to 1.20 m, carrying dense clouds of flowers. They’re ideal at the back of a border and also make excellent cut flowers for a vase.

Panicle phlox: a classic with reliable fragrance

Panicle phlox (Phlox paniculata) produces large, scented flower heads and looks at its best from June to September. Paired with asters, coneflowers or delphiniums, it creates a true cottage-garden feel.

Popular varieties include:

• ‘Tenor’ - intense raspberry red, exceptionally bright in the border.
• ‘Orange Perfection’ - unusual, striking vermilion tones; ideal as a focal point.
• ‘Blue Paradise’ - blue-violet; the colour reads cooler or warmer depending on the light.
• ‘Bright Eyes’ - soft pink blooms with a darker centre; very romantic.
• ‘Fuji Yama’ - pure white and rather late-flowering, extending the season into late summer.

Spotted phlox: earlier flowering and a slimmer habit

Spotted phlox (Phlox maculata) grows more narrowly, but makes up for it with distinctive, candle-like flower spikes. It usually flowers a little earlier, typically from July to August, and reaches 80 cm to 1 m tall.

Notable varieties:

• ‘Alpha’ - sweet-shop pink with a slight violet sheen, flowering on into September.
• ‘Natascha’ - white-and-pink striped blooms that stand out immediately.

Gap-fillers with months of colour: annual phlox for pots and borders

Drummond phlox: compact, but endlessly floriferous

If you want a genuine wave of flowers from spring until the first frosts, choose Drummond phlox (Phlox drummondii). These annual forms stay much lower at around 20 to 40 cm, but repay you with exceptionally long, generous flowering.

The colour range leaves very little to be desired:

• From pure white through cream and salmon to strong red and deep blue.
• Bicolours with a contrasting eye or striped petals.
• Mixed colour blends that practically spill over window boxes, pots and border edges.

Drummond phlox is just as happy in the ground as it is in containers, balcony boxes or shallow bowls. It’s especially well suited to city balconies because it takes up little space while delivering maximum colour impact.

Where phlox has the biggest impact in the garden

Phlox is considered a true all-rounder in ornamental planting. It slips into very different looks with ease - from a neat, structured perennial border to a wilder, nature-inspired garden.

Typical ways to use it include:

• In mixed perennial borders: Combined with asters, coneflowers, purple coneflower or lady’s mantle, it creates a loose, colourful summer scene.
• Along fences or in front of a fence: Tall forms hide unattractive areas and provide a flowering backdrop.
• In pots or bowls: Compact options such as Drummond phlox bring colour to patios and balconies.
• As a cut flower: Panicle phlox lasts well in a vase, adding fragrance and colour indoors.

"If you place phlox thoughtfully, a handful of plants is enough to add depth to a border and create a smooth transition from front to back."

Golden rules for healthy phlox

To keep phlox thriving for years, it helps to stick to a few essential care points. The plant is generally easy-going, but it does have clear preferences.

Aspect	What phlox likes
Planting time	Perennial types in spring or autumn; annual types sown into the border from late spring
Light	Sun to light partial shade
Soil	Nutrient-rich and loose; never completely dried out in summer
Care	Remove spent flowers; feed occasionally with compost
Rejuvenation	Divide perennial types every few years in autumn

One issue that’s often underestimated: phlox is sensitive to persistently damp, poorly ventilated spots. That’s where powdery mildew can appear, showing up as a whitish coating on the leaves. A position with air movement, good soil and adequate spacing is the better choice.

Practical tips for longer flowering and stronger plants

With a bit of attention, you can get even more from your phlox. Small tweaks can make a big difference:

• In spring, work in a thin layer of compost to encourage vigorous growth.
• Cut off faded flower heads to prompt new blooms and keep self-seeding under control.
• During very hot summers, water deeply in the morning rather than giving frequent light sprinkles.
• If powdery mildew becomes a problem, choose resistant varieties or intervene early with approved treatments.

By combining several varieties, you can extend the flowering period: early, mid-season and late types ensure the border never looks empty from early summer into autumn. Mixing white, pastel and strong shades also adds interest - white acts like a “light switch” in the border, making surrounding colours look more intense.

Partial shade can be especially effective too. Cooler violet and blue varieties shine there because they almost glow in softer light. In full sun, bold reds and bicolours work brilliantly, staying visible from a distance and giving the garden clearer structure.

If you load a few pots of phlox into the trolley this March, you’re laying the groundwork for a summer that won’t be short on colour. With minimal effort, a few straightforward rules and the right variety choices, an average border becomes a spot you’ll want to linger in on warm evenings.