10 of the best summer flowering shrubs

Roses - summer flowering shrubs

Why grow summer flowering shrubs?

If your aim is for your garden in summer to burst with colour and life, then choosing the right summer flowering shrubs can help you achieve exactly that.

The right shrubs can be visually powerful in themselves and add to the overall diversity of your garden in three main ways.

Firstly, summer flowering shrubs are invaluable for establishing a cycle of continuous flowering. You can enjoy a seamless progression of blooms by carefully selecting species and varieties that flower at different times throughout the summer. For example, you could go from early bursts of forsythia and rhododendron to the late-summer splendour of hibiscus and hydrangea

Secondly, summer flowering shrubs play a crucial ecological role. They are key contributors to the local ecosystem, offering food and habitat to wildlife.

Their flowers attract pollinators like bees and butterflies that are essential for pollinating many plants and crops. Additionally, the dense foliage and branch structures of shrubs provide excellent shelter and breeding spots for birds and small mammals.

Finally, summer flowering shrubs offer versatile design possibilities. They can create natural privacy screens, hide unsightly views, or reduce noise pollution. Their varied heights, textures, and forms allow creative gardeners to enhance their space, defining borders, framing garden paths, or creating focal points and secluded nooks.

Here, we explore ten superb summer flowering shrubs, detailing their growth habits, floral displays, and the best cultivars to cultivate for a spectacular garden show.

1. Hydrangea macrophylla (Bigleaf Hydrangea)

Hydrangea macrophylla

The classic Hydrangea, Hydrangea macrophylla, is a garden favourite for its robust growth and versatile floral display, which changes colour based on the soil’s pH level. There will be more lilac/blue flowers on acid soil, while alkaline soil gives rise to pink flowers.

This shrub’s large, vibrant blooms make it a feature plant for any garden, offering a great backdrop or focal point. It thrives in partial shade, making it ideal for adding brightness to those shadier areas of a garden. There is a bit of a trick to getting Hydrangea pruning right, but we cover that here.

  • Height/Width: Typically 3-6 feet (90 to 180cm) tall and wide.
  • Foliage: Large, lush green leaves.
  • Flowers: Large, round flower heads in shades of blue, pink, white, or purple, depending on soil pH.
  • Flowering Time: Early to late summer.
  • Growing Conditions: Prefers partial shade and moist, well-drained soil.
  • Top Cultivars:
    • ‘Endless Summer’: Remarkable for its ability to bloom on both old and new wood; flowers can be blue in acidic soils or pink in alkaline soils.
    • ‘Nikko Blue’: Known for its large, vibrant blue flowers.
    • ‘Madame Emile Mouillère’: Sports snowy white blooms that gradually turn pinkish with age.

2. Rosa (Shrub Roses)

Rosa Sally Holmes
Rosa ‘Sally Holmes’ Large-flowered Climbing Rose bred by Robert A Holmes, introduced in 1976 in the UK and named after his wife” by cultivar413 is licensed under CC BY 2.0

Shrub Roses are ever popular for their resilience and prolonged blooming period, making them an indispensable part of any summer garden. They provide a continuous display of stunning flowers from late spring through to autumn/fall, and are available in a large variety of colours and forms. Roses are beautiful and, in many cases, fragrant and can serve multiple landscape functions. For example, you can grow them as a focal point or specimen plant, in mixed borders or on arbours and fences.

  • Height/Width: Varies widely; typically 2-5 (60 to 75cm) feet in both dimensions.
  • Foliage: Deciduous, glossy, often dark green leaves.
  • Flowers: Come in many colours and forms, generally very fragrant.
  • Flowering Time: Repeat from late spring through fall.
  • Growing Conditions: Full sun, well-drained soil.
  • Top Cultivars:
    • ‘Knock Out’: Renowned for disease resistance and continuous bloom; flowers are cherry red.
    • ‘Sally Holmes’: Creamy white blossoms with a slight blush, cluster-flowered.
    • ‘Golden Wings’: Single yellow flowers with prominent stamens.

3. Buddleia davidii (Butterfly Bush)

Buddleia davidii 'Black Knight'
Buddleia davidii ‘Black Knight’ by Starr Environmental is licensed under CC BY 2.0

Buddleja davidii, commonly known as the Butterfly Bush, is renowned for attracting pollinators to the garden. Its long, arching branches are tipped with panicles of fragrant flowers throughout midsummer to early autumn. This shrub is particularly valued for its ability to thrive in poor soils and recover from harsh conditions or hard pruning. Its rapid growth and prolific flowering habit make it a fantastic choice for creating wildlife-friendly gardens that buzz with life.

  • Height/Width: Can reach up to 10 feet tall and wide, but many cultivars are smaller.
  • Foliage: Long, narrow leaves, grey to green in colour.
  • Flowers: Spiky panicles of purple, white or pink flowers.
  • Flowering Time: Mid-summer to early autumn.
  • Growing Conditions: Full sun, most soils.
  • Top Cultivars:
    • ‘Black Knight’: Deep violet-blue flowers, very attractive to butterflies.
    • ‘White Profusion’: Abundant creamy-white flowers.
    • ‘Pink Delight’: Bright pink blooms with a sweet scent.

4. Spiraea japonica (Japanese Spirea)

Spirea japonica - summer flowering shrub

Japanese Spirea is a durable, low-maintenance shrub that bursts into colour with vibrant flowers and attractive foliage. It works well in city gardens as it is compact in size and able to withstand urban pollution. The shrub’s repeat blooming through the season offers lasting visual interest, which its colourful autumn leaves can enhance. Spiraea japonica’s adaptability to various growing conditions and pruning tolerance make it a versatile choice for any garden setting.

  • Height/Width: Generally 2-3 feet tall and wide.
  • Foliage: Deciduous, with leaves turning bronze-red in fall.
  • Flowers: Dense clusters of pink or white flowers.
  • Flowering Time: Early to mid-summer.
  • Growing Conditions: Full sun, tolerates a range of soil types.
  • Top Cultivars:
    • ‘Goldflame’: Bronze-red new foliage, maturing to yellow-green with pink flowers.
    • ‘Little Princess’: Compact form with delicate pink blooms.
    • ‘Shirobana’: Unique because it produces pink and white flowers on the same plant.

5. Ceanothus (California Lilac)

Beautiful Ceanothus in full flower in my garden in late May

California Lilac is celebrated for its dazzling blue flowers that appear in profusion from late spring, creating a powerful visual impact in the garden. Once established, this shrub is extremely drought-tolerant, making it perfect for drier climates.

Ceanothus can vary in size from compact ground covers to larger shrubs, providing options for different garden scales. It has evergreen foliage and is highly attractive to pollinators. Overall, Ceanothus is a great choice for gardeners looking for a sustainable and low-maintenance shrub.

  • Height/Width: Varies; from low ground covers to 20-foot-tall shrubs.
  • Foliage: Evergreen, glossy leaves.
  • Flowers: Dense clusters of blue, white, or pink flowers.
  • Flowering Time: Late spring to early summer.
  • Growing Conditions: Full sun, well-drained soil, drought tolerant once established.
  • Top Cultivars:
    • ‘Concha’: Deep blue flowers, one of the hardiest.
    • ‘Victoria’: Dark blue flowers, robust and reliable.
    • ‘Skylark’: Bright blue flowers, more compact form.

6. Weigela florida

Weigela florida
Weigela florida by Opiola Jerzy is licensed under CC BY-SA 2.5

Weigela florida is a versatile shrub that offers a spectacular show of flowers in late spring, often re-blooming throughout the summer. Its arching branches give it a graceful appearance, while the variety of cultivars ensures there is a Weigela to suit any garden’s colour scheme.

Particularly noted for its decorative leaves, some cultivars display variegated or deep burgundy foliage. This shrub’s adaptability and vibrant presence make it a favourite among gardeners looking for easy care and high impact.

  • Height/Width: Typically 3-6 feet tall and wide.
  • Foliage: Deciduous, often with a burgundy or gold tint, some cultivars are variegated.
  • Flowers: Bell-shaped flowers in shades of pink, red, or white.
  • Flowering Time: Late spring, with a repeat bloom in late summer.
  • Growing Conditions: Full sun to part shade, adaptable to many soil types.
  • Top Cultivars:
    • ‘Wine and Roses’: Rosy-pink flowers with dark burgundy foliage.
    • ‘My Monet’: Variegated foliage with pink flowers, dwarf form.
    • ‘Red Prince’: Vivid red flowers that retain their color well.

7. Philadelphus (Mock Orange)

Philadephus lewisii
“Philadelphus lewisii by John Rusk is licensed under CC BY 2.0

Mock Orange is valued for its heady fragrance and the elegant simplicity of its white flowers, which appear to glow in the garden’s dusk light. It can flourish in a range of soil types and in full sun or partial shade. So it is highly versatile. The shrub’s dense growth also makes it a useful privacy screen during the summer months.

  • Height/Width: 3-10 feet tall, similar spread.
  • Foliage: Deciduous, oval leaves.
  • Flowers: Fragrant, white blooms reminiscent of orange blossoms.
  • Flowering Time: Late spring to early summer.
  • Growing Conditions: Full sun to part shade, well-drained soil.
  • Top Cultivars:
    • ‘Belle Etoile’: Single white flowers with a maroon center.
    • ‘Minnesota Snowflake’: Double white flowers, very floriferous.
    • ‘Avalanche’: Single white flowers, notable for its abundance of blooms.

8. Viburnum plicatum (Japanese Snowball)

viburnum plicatum mariesii
Viburnum plicatum mariesii by peganum is licensed under CC BY-SA 2.0

The Japanese Snowball is a robust shrub known for its beautiful, layered branches and striking, ball-like clusters of white flowers. It offers year-round interest with its vibrant fall foliage and structured form, which provides strong winter interest. Easy to grow and requiring minimal maintenance, this shrub is ideal for creating a focal point in the landscape.

  • Height/Width: Up to 8 feet tall and wide.
  • Foliage: Deciduous, deeply veined, dark green leaves.
  • Flowers: Large, round clusters of white flowers resembling snowballs.
  • Flowering Time: Mid to late spring.
  • Growing Conditions: Full sun to partial shade, prefers moist, well-drained soils.
  • Top Cultivars:
    • ‘Mariesii’: Horizontal branches with lacecap-style flowers.
    • ‘Popcorn’: Snowball-like blooms, bushier form.
    • ‘Watanabe’: Small lacecap flowers, blooms intermittently throughout summer.

9. Clethra alnifolia (Summersweet)

Clethra alnifolia Hummingbird
Clethra alnifolia ‘Hummingbird’ x ‘Anne Bidwell’ by Plant Image Library is licensed under CC BY-SA 2.0

Summersweet (Clethra alnifolia) is a North American native shrub that produces fragrant, white or pink flower spikes in mid to late summer. Summersweet is relatively low-maintenance and thrives in moist, acidic soil conditions. It can do well in partial shade, making it a useful plant for gardeners with shady areas to fill.

  • Height/Width: Up to 8 feet tall and 6 feet wide.
  • Foliage: Deciduous, dark green leaves.
  • Flowers: Fragrant, upright spikes of small, pink or white bell-shaped flowers.
  • Flowering Time: Mid to late summer, typically from July to September.
  • Growing Conditions: Partial shade to full sun, prefers mist acidic soils.
  • Top Cultivars:
    • ‘Ruby Spice’ – Deep pink flower spikes
    • ‘Hummingbird’ – White, fragrant flowers
    • ‘Sixteen Candles’ – White flower spikes, compact habit

10. Lavandula (Lavender)

Lavendar 'Munstead'
“Lavendar (Munstead)” by Linda N. is licensed under CC BY 2.0

Lavender is prized for its fragrant and soothing flowers and for its ability to withstand drought, making it a staple in hot, dry, mediterranean style gardens. Its evergreen foliage provides year-round interest, and in high summer its flowers are usually alive with bees and butterflies.

Lavender is perfect for borders, herb gardens, or as a fragrant ground cover. With its therapeutic qualities and stunning visual appeal, Lavender remains a top choice for gardeners seeking beauty and practicality in their plantings.

  • Height/Width: Typically 1-3 feet tall and wide.
  • Foliage: Evergreen, narrow, silver-green leaves.
  • Flowers: Fragrant spikes of purple, lavender, or white flowers.
  • Flowering Time: Early to late summer.
  • Growing Conditions: Full sun, well-drained soil, drought tolerant.
  • Top Cultivars:
    • ‘Hidcote’: Deep purple flowers, compact and popular for borders.
    • ‘Munstead’: Dwarf form with lavender-blue flowers, excellent for small spaces.
    • ‘Phenomenal’: Robust and winter hardy with violet-blue flowers.
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