Expert Guide: How to Fill Gaps in Hedges – Leylandii, Privet, and More

Seeing unsightly gaps in a mature hedge can be frustrating, but with the right techniques you can restore a tidy, attractive boundary. Below is a step‑by‑step guide that draws on decades of horticultural experience to help you fill gaps in any hedge type.

Effective Strategies for Closing Hedge Gaps:

• Mask the bare base with strategically planted companions.
• Introduce flowering shrubs for color and density.
• Re‑train neighboring branches to cover voids.
• Add decorative garden ornaments to shift focus.
• Install wood gratings, vines, trellises, or structural elements to create visual closure.

These methods are simple, adaptable, and, most importantly, they support the overall health of your hedge. Keep reading for detailed guidance on each approach and how to apply them to Leylandii, Privet, and deciduous hedges.

Mask the Bare Bottom

When the base of your hedge appears thin or open, plant taller, vigorous companions in front of the deficit. Larger species are essential because smaller plants won’t fill the space as the hedge is trimmed over time.

Add Flowering Shrubs

Choose small‑to‑medium flowering shrubs to fill gaps and introduce seasonal blooms. This dual benefit enhances privacy while adding aesthetic interest.

Re‑train Adjacent Branches

Use gentle ties or clips to redirect shoots from neighboring plants toward the gap. With consistent guidance, these branches will grow into the void, naturally closing the space.

Incorporate Decorative Ornaments

Front‑plant or mount lightweight ornaments such as wind chimes, lanterns, or decorative stakes. These elements distract the eye from imperfections and can be swapped seasonally.

Use Structures to Conceal Gaps

Attach vine‑friendly trellises or thin wood panels behind the hedge. When vines climb or when the structure is visible from the front, the hedge’s irregularities become less noticeable.

Essential Tips for Successful Gap Filling

• The companion plant choice depends on hedge species. For ideas, see What To Plant Under Hedges [7 Ideas Including Flowers!].
• Respect root zones—dig slowly to avoid severing established roots, and give new plants enough room to thrive.
• Plant companions close enough to cover gaps but not so tight that they compete for nutrients.
• Maintain a consistent watering and fertilisation schedule to keep both hedge and additions healthy.
• Regular pest and disease inspections will prevent new gaps from forming.
• For base gaps, dig a one‑foot trench, amend with compost, and plant shade‑tolerant shrubs such as Bergenia or Persian ivy.

Filling Gaps in a Leylandii Hedge

Leylandii (Leyland cypress) is prized for its rapid growth, dense foliage, and evergreen privacy. When gaps appear, consider adding companion plants that thrive under its canopy.

Recommended companions include:

• Bergenia
• Climbing hydrangea
• Fargesia bamboo
• Griselinia
• Laurel
• Persian ivy

Should a gap be substantial, a new Leylandii sapling can be inserted to reinforce density.

Filling Gaps in a Privet Hedge

Privet offers a self‑propagating, dense hedge at a low cost. To address gaps, prop up understory companions such as:

• Aspidistra (Cast Iron Plant)
• Ferns (e.g., Bracken)
• Geranium
• Sweet woodruff
• Rusty foxglove

Summer pruning of the base can stimulate new growth, helping the hedge self‑self‑propagate into the void.

Self‑Propagating Deciduous Hedges (Hawthorn, Beech, etc.)

For deciduous species, the best practice is to plant bare‑root or root‑wrapped specimens during the fall. This timing takes advantage of cooler temperatures and abundant soil moisture.

Common hedge layers for these species are:

• Ash
• Blackthorn
• Elm
• Field maple
• Hazel

Consider a short winter cut‑back to encourage vigorous regrowth from old wood.

Why Gaps Occur

• Insufficient Sunlight – Gaps often appear at the base where light is blocked.
• Over‑Pruning – Cutting young shoots can halt growth and leave voids.
• Pests & Diseases – Targeted attacks weaken branches and create gaps.
• Environmental Stress – Winter cold, heavy snow, wind, and storms can break delicate branches.

Takeaway

Gaps in hedges can be remedied with thoughtful plant selection, structural additions, and diligent care. By following these evidence‑based techniques, you’ll restore a dense, attractive barrier that enhances both privacy and curb appeal.

Author: Rachel Self
Rachel is a gardening enthusiast and plant curator who specialises in integrating greenery into living spaces. She enjoys discovering creative plant uses and sharing her knowledge with fellow garden lovers.

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Editorial Oversight
GardenTabs content is reviewed by Steve Snedeker, a seasoned gardener with decades of hands‑on landscaping experience.