Thuja (Thuja spp.) can be cut multiple times per year, with timing depending on growth and local regulations. In general, the best windows are during active growth in spring to early autumn, avoiding late summer heat and bird- nesting periods. Direct answer
- Optimal cutting windows: spring after last frost (around April) through early autumn (around September) while the plant is actively growing. If you trim only once a year, do so in late spring or early summer after the new shoots have begun to form. For fuller hedges, a second cut in late June is common, and a third light cut in late August can be beneficial for shaping.
- Frequency recommendations:
- Light maintenance: 1 cut per year (late summer) to maintain shape.
- Regular shaping: 2 cuts per year (early spring and late summer).
- Heavy or dense hedges: 3 cuts per year (early spring, late spring/early summer, and late summer).
- Practical notes:
- Avoid radical reductions in midsummer due to bird protection rules in many regions; large weekend i cuts may be restricted during the breeding season.
- Deeper reductions should be planned in cooler, cloudy days to reduce scorch and sunburn on fresh growth.
- If growth is very vigorous, limit new growth to about 3–5 cm per season to encourage branching and a dense habit.
- Wet leaves increase fungal risk, so postpone cuts when leaves are wet or after heavy rainfall.
If you share your country/region and whether you’re pruning a formal hedge or a specimen plant, the exact timing and limits can be tailored to local guidelines and your specific goals.
