Can You Trim the Bottom of Arborvitae?
Short answer: yes — but with caution. Arborvitae are beautiful, dense evergreen screens that many of us rely on for privacy and year‑round color. Trimming the lower portion of an arborvitae can give a tidy look, create a formal trunk, or clear space for underplanting, but do it wrong and you’ll end up with a bare, unsightly lower trunk that won’t recover. I’ve learned this the hard way and I’ll share what works, what doesn’t, and how to keep your arborvitae healthy and attractive.
Why Trimming the Bottom Is a Common Question
Gardeners want clean lines, easy mowing access, and space for flower beds under hedges. The problem is arborvitae don’t behave like roses or boxwood. Their foliage is mostly on the outer green growth. If you remove too much of that green, the inner brown wood rarely sprouts new growth, leaving bare trunks or “skirted” hedges. Before you cut, think about why you want to trim and whether the plant can tolerate it.
Common reasons people trim the bottom
- To create a clear trunk for a neat, formal look
- To allow foot traffic, mowing, or planting underneath
- To remove damaged lower branches from winter burn or pests
- To rejuvenate a thinning base (sometimes attempted)
What Happens If You Trim the Bottom Wrong
Arborvitae tend not to regenerate from old brown wood. Cut back into bare wood and you usually won’t get new foliage below the cut. That leaves a visible bare trunk and a lollipop look where the top remains green but the lower section is naked. I trimmed one of my Thuja hedges down too aggressively in early spring one year and spent three seasons nursing new plantings at the base to disguise the bare legs.
“When I rescued a hedge that someone had stripped at the bottom, I learned that patience and small, gradual cuts work far better than a drastic chop.” — Your friendly neighborhood gardener
How to Safely Trim the Bottom of Arborvitae
Follow these steps to trim the lower part of arborvitae without killing the plant or leaving permanent bare spots.
Best timing
- Late spring to early summer after the new soft growth has hardened off is ideal.
- Avoid heavy pruning in late summer or fall — new shoots won’t harden before winter and can suffer cold damage.
Tools to use
- Sharp hand pruners for small stems
- Loppers for thicker lower branches
- Pruning saw for large limbs
- Gloves and safety glasses
Step-by-step technique
- Stand back and decide how much green growth you must keep. Never cut into brown wood unless you accept the risk of no regrowth.
- Remove individual lower branches back to the main trunk rather than shearing the foliage. This keeps the natural shape and reduces stripping live tissue.
- If you want a formal trunk, gradually raise the bottom over two to three seasons. Remove a few lower branches each year rather than all at once.
- Angle cuts slightly and make clean cuts close to the collar without tearing bark.
- If you must cut into older wood, trim a little and monitor; avoid repeated deep cuts in the same area.
When Rejuvenation Is Possible
If your arborvitae has mild thinning low down but still has green tissue close to the base, light pruning can encourage denser growth. Some cultivars respond better than others. Rejuvenation pruning — cutting the plant to a lower height — can work if there are live buds near the base, but it’s risky and slow. I once cut back a small, crowded hedge to about one foot above the ground. It produced new shoots after a season, but only because the plants still had some live basal buds and I kept them watered and fed.
When rejuvenation is unlikely
- When the lower wood is brown and dry — no green tissue visible
- When the plant has been heavily shaded for years and lacks basal vigor
- During drought stress or after severe winter burn
Alternatives to Trimming Bottoms
If you don’t want the risk of bare trunks, consider these options.
- Raise the surrounding soil level slightly when planting so lower branches sit higher naturally.
- Plant low-growing shrubs or shade-loving perennials in front to mask the lower trunk.
- Train the hedge gradually — remove a few lower branches each year to create a clear trunk slowly.
- Space new plantings with adequate light so lower growth develops from the start.
Dealing with Common Problems That Cause Lower Dieback
Trimming isn’t always the cause of bare bottoms. Often it’s a symptom of other issues:
- Shade: lower branches die when starved of light
- Water stress: irregular watering causes dieback
- Soil compaction or poor drainage: root stress leads to dying lower foliage
- Pests and disease: bagworms, scale, or fungal issues can damage lower growth
- Winter burn and desiccation: lower exposed foliage can be damaged by salt or wind
My Practical Advice
I tend to avoid heavy bottom pruning on mature arborvitae. If I want a cleaner base, I plant with that in mind, raise the planting soil slightly, or gradually remove lower branches over multiple seasons. When I do trim, I keep cuts conservative and watch the plant’s response for a year. Patience wins — arborvitae recover slowly but reliably when treated gently.
Final Takeaway
Yes, you can trim the bottom of arborvitae, but do so carefully. Preserve green growth, avoid cutting into brown wood, and consider gradual trimming or alternatives like underplanting if you want a neat base. With the right timing and technique, you can achieve a tidy, healthy arborvitae without turning it into a bare‑legged eyesore.
