Garden

How to Trim a Hedge Straight

Use a string line to cut hedge tops and sides level. A straightforward way to keep formal hedges looking sharp and tidy.

OMBy Olena Marchenko · AI-assisted editorReviewed 5/31/2026

Quick answer

Tie a string line between stakes to set the height and width. Spread a sheet to catch clippings. Trim the top first, then the sides, following the guides. Step back often to check for straightness. Sweep up when done.

Straight hedge edges give a garden a crisp, formal look. A simple string line removes guesswork and helps you cut an even line every time.

What you’ll need

  • hedge shears or electric trimmer
  • long string line and stakes
  • garden broom
  • rake
  • gloves
  • sheet or tarp

Step by step

  1. 1

    Set up guides

    Push stakes into the ground at both ends of the hedge. Tie a string line between them at the height and width you want. Check it is level with a spirit level or by eye.

  2. 2

    Lay a sheet

    Spread a sheet or tarp on both sides of the hedge. This catches clippings and saves raking later.

  3. 3

    Cut the top

    Start at one end. Cut along the string line, taking off small amounts at a time. Step back every few metres to check the line is straight. Do not overreach.

  4. 4

    Cut the sides

    Use a second vertical string line if the hedge is wide. Trim from bottom to top so falling clippings do not hide untrimmed growth. Keep the blade parallel to the hedge face.

  5. 5

    Tidy up

    Rake clippings from the sheet into a barrow. Sweep the pavement or lawn. Check the hedge for any stray branches and snip them.

Electric trimmers and shears can cause serious cuts. Keep the cable over your shoulder and away from the blade. Wear gloves and eye protection. Do not use electric tools in wet conditions. Check for nesting birds before cutting; it is illegal to disturb active nests in many regions.

Common mistakes

  • Cutting too deep in one pass. Remove small amounts. You cannot put branches back.
  • Trimming without guides. Freehand cutting rarely gives a straight finish.
  • Ignoring nesting birds. Check the hedge for birds between March and August before you start.
  • Trimming wet hedges with electric tools. Water and electricity are a dangerous mix. Wait for dry weather.

Frequently asked

When is the best time to trim a hedge?

Trim formal hedges in late spring and again in late summer. Avoid cutting in freezing weather or during active bird nesting season.

How do I fix a hedge that is wider at the top?

Cut the top back harder than the sides so the face slopes slightly inward. This lets light reach the lower branches and prevents bare legs.

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