Tooth spacing for arborvitae versus boxwood

Arborvitae generally benefits from wider hedge trimmer tooth spacing than boxwood. For fine boxwood shaping, a blade with about 3/8- to 1/2-inch tooth spacing is usually the better fit. Arborvitae often calls for about 5/8- to 3/4-inch spacing, especially when the hedge contains thicker, older stems. Always compare the blade’s stated maximum cutting capacity with the actual branches you plan to cut.

What tooth spacing means

Tooth spacing is the distance between adjacent cutting teeth on the blade. It affects both the type of growth the trimmer can engage and the finish it leaves behind.

• Smaller spacing: Better for thin stems, soft new growth, and precise shaping
• Wider spacing: Better for thicker stems and dense, coarser growth
• Larger spacing does not automatically mean a cleaner cut: It can be less precise on small-leaved shrubs

Tooth spacing is different from blade length. A longer blade covers more hedge with each pass, while tooth spacing determines how much material can fit between the teeth.

Best spacing for boxwood

For most boxwood, choose a hedge trimmer with 3/8- to 1/2-inch tooth spacing. Boxwood has relatively small leaves and is commonly clipped into detailed shapes, so a close tooth pattern helps produce a more controlled finish.

A smaller gap is particularly useful when:

• You are maintaining a formal boxwood shape
• Most of the growth is thin and green
• You want to avoid pulling or skipping over small stems
• The hedge is young or regularly maintained

A wider blade gap may still work on an overgrown boxwood, but it is not necessarily an advantage for routine shaping. If the trimmer is rated for branches thicker than the stems you need to cut, it may feel less refined during light trimming.

Best spacing for arborvitae

Arborvitae commonly needs 5/8- to 3/4-inch tooth spacing because established plants can develop thicker, tougher stems beneath the outer foliage. This spacing gives the blade more room to engage branches without constantly clogging or bouncing away from the material.

A wider gap is most useful when:

• The arborvitae hedge has been allowed to grow out
• You are cutting more than soft, current-season tips
• The hedge contains woody interior stems
• The trimmer’s motor and blade are rated for the intended branch diameter

For young arborvitae or frequent light maintenance, a smaller gap can still be suitable. Do not choose spacing based only on the plant name; inspect the thickest stems you expect to cut and compare them with the manufacturer’s cutting-capacity specification.

Quick comparison

These are practical selection ranges, not universal requirements. Blade designs vary, and the manufacturer’s stated cutting capacity takes priority.

Do not confuse tooth spacing with cutting capacity

A blade’s tooth spacing and its maximum branch capacity are related, but they are not identical specifications. Two trimmers with similar tooth spacing can have different cutting limits because of differences in motor power, blade movement, tooth shape, and construction.

Before trimming, check:

1. The maximum branch diameter listed in the owner’s manual
2. Whether that rating applies to the specific blade installed
3. Whether the blade is intended for green growth, woody stems, or both
4. Whether the hedge contains branches larger than the trimmer is designed to cut

If arborvitae has mature woody branches beyond the trimmer’s rating, use hand pruners, loppers, or a suitable pruning saw instead. Forcing a hedge trimmer into oversized wood can stall the motor, damage the blade, or create a kickback hazard.

Blade length still matters

Tooth spacing determines how the blade engages the stems, but blade length affects reach and handling.

• Shorter blades are easier to control for boxwood shaping and narrow hedges.
• Longer blades can make straight arborvitae faces faster to trim, but they may be heavier and harder to maneuver.
• A longer blade does not compensate for tooth spacing that is too small or a cutting-capacity rating that is too low.

Choose the shortest blade that comfortably covers the hedge’s width if control and precision matter most. Choose more length when you need efficient, even passes across a broad arborvitae face and can safely manage the added reach.

How to get a cleaner cut

Use the correct spacing, but also pay attention to technique:

• Trim boxwood with light, controlled passes rather than forcing the blade through dense sections.
• Keep arborvitae passes shallow when shaping the outer layer.
• Avoid cutting into old, bare arborvitae wood unless the plant and variety are known to regenerate from that area.
• Keep the blade clean and lubricated according to the manufacturer’s instructions.
• Stop and remove packed foliage only after switching off the trimmer, disconnecting the battery or unplugging the tool, and allowing moving parts to stop.
• Wear eye protection, sturdy footwear, and hearing protection where appropriate.

Never hold branches in place near the moving blade. For corded or gas-powered trimmers, follow the manufacturer’s instructions for safe startup, extension cords, fuel, and storage.

Which spacing should you choose?

Choose 3/8 to 1/2 inch if your priority is detailed boxwood shaping and most stems are thin. Choose 5/8 to 3/4 inch for a mature arborvitae hedge with thicker woody growth. If you maintain both plants, a medium spacing around 1/2 to 5/8 inch can be a practical compromise when neither hedge has unusually thick branches.

If the existing blade is dull, bent, or damaged, replace it with a blade that matches the exact trimmer model and mounting pattern. A replacement blade with the right tooth spacing will not be safe or useful if it does not fit the tool or exceeds its approved specifications.