Arborvitae hedges are everywhere in Rochester, doing the job of a fence along property lines across the whole county. Which means when they start browning, a lot of people want an answer quickly.
Tip blight is one of the more common causes and one of the more misread, because the damage looks like winter burn, drought, or spider mites depending on when you catch it.
What is tip blight, and which fungus is it?
Two different fungi produce a very similar result. Penn State describes juniper twig blights caused by Phomopsis and Kabatina as two of the most damaging diseases affecting junipers in the Northeast, and notes they also infect American and Oriental arborvitae, hinoki cypress and English yew.
That host list matters locally, because it covers most of what gets planted as evergreen screening around here.
The primary symptom of Phomopsis blight is browning and dieback of new shoot tips in spring. The young growth turns a dull ashen gray, then browns, and the dieback progresses back from the tip toward older wood. A small lesion often forms where the dead tissue meets living tissue.
Kabatina produces the same visual result on a different schedule and on different tissue. It attacks the previous season's growth and becomes visible in late winter to early spring, before the new flush.
How do I tell Phomopsis from Kabatina, and does it matter?
Timing and tissue age are the separators.
| Phomopsis tip blight | Kabatina tip blight | |
|---|---|---|
| Tissue attacked | Current-season new growth | Previous season's growth |
| When symptoms show | Spring and through the growing season | Late winter into early spring |
| Typical entry | Infects young succulent tissue directly | Often enters through wounds and injury |
| Repeat infection | Can reinfect through the season in wet weather | Generally a single period |
| Response to fungicide | Preventive timing on new growth can help | Poorly suited to fungicide timing |
For a homeowner the distinction mostly changes one thing: whether a preventive fungicide has any point. Phomopsis infects new growth, so protecting that growth as it emerges is at least coherent. Kabatina's timing makes fungicide largely irrelevant, and management falls entirely to pruning and cultural work.
Both are worse in wet conditions and on plants that stay damp, which is why sheared hedges with dense interiors and poor air movement suffer disproportionately.
Field note · When to call a pro
Want a certified arborist to take a look?
Monster Tree Service of Rochester offers free estimates and a full plant health care program across the Rochester area.
Get a Free Estimate →What actually controls it?
Penn State is direct on this: removal of old dead twigs and branches is very important for control of both diseases.
That is the intervention, and it is unglamorous. The dead tissue holds the fungus and produces the spores that infect the next flush of growth. Leaving it in the hedge means reinfection every year regardless of anything else you do.
Practically, that means pruning out dead tips back into healthy wood, doing it in dry weather rather than wet, disinfecting tools between cuts on a badly affected plant, and getting the prunings off site rather than piling them nearby.
Beyond pruning, the useful work is about keeping foliage dry and plants unstressed. Avoid overhead irrigation, especially in the evening. Do not plant screening hedges so tightly that air cannot move through them. Avoid shearing into a solid wall that keeps the interior permanently damp. And keep the plants adequately watered in drought, because stressed plants take infection worse.
If the browning turns out not to be tip blight at all, our guide to evergreens turning brown in Rochester works through the alternatives, and arborvitae turning brown covers that species specifically.
What else browns an arborvitae or juniper in Rochester?
Several things, and misidentifying this costs a season.
- Winter burn. Browning on the windward and sun-exposed side, appearing in late winter, uniform across older and newer foliage rather than concentrated at tips. Our guide to sunscald and frost cracks in a Rochester winter covers the related trunk damage.
- Spruce spider mite. Stippled, dusty-looking foliage with fine webbing, worse in hot dry stretches. See spruce spider mite on Rochester evergreens.
- Bagworms. Small spindle-shaped bags hanging from foliage, made of the plant's own material. See bagworms on arborvitae and spruce.
- Road salt. Browning concentrated on the road or driveway side. Our guide to salt-tolerant trees and shrubs for Rochester driveways covers placement.
- Root problems. Poor drainage, planting too deep, or compaction, all of which brown a plant from the inside out rather than from the tips.
The tip-first pattern is the tell for blight. Damage that starts at the outer tips of young shoots and works backward points at these fungi. Damage that is uniform across a whole side, or that starts in the plant's interior, points elsewhere.
When is a hedge worth saving?
This comes down to how much is affected and whether the plants are otherwise sound.
Scattered tip dieback across a hedge, with the plants otherwise dense and growing, is a pruning-and-culture problem worth addressing. Individual plants that are more than half brown, or that have dieback well back into old wood, rarely recover into an acceptable screen even if they survive, because juniper and arborvitae do not readily regenerate from bare old wood.
In a hedge, replacing one or two failed plants inside an otherwise healthy run is usually better than trying to nurse them back. Matching the replacement to the same species and cultivar matters for appearance, and our comparison of emerald green versus green giant arborvitae covers the two most common choices in this region.
Field note · When to call a pro
Want a certified arborist to take a look?
Monster Tree Service of Rochester offers free estimates and a full plant health care program across the Rochester area.
Get a Free Estimate →FAQ
My arborvitae hedge browned over the winter. Is that tip blight?
Possibly, but winter burn is more common and looks different. Burn is usually concentrated on the windward or sun-exposed side and affects foliage of all ages uniformly. Blight starts at the tips of shoots and works backward. Check whether the browning follows the exposure or follows the youngest growth.
Do I need to spray?
Often not. Removing dead twigs is the intervention Penn State emphasizes for both diseases, and it addresses the source of next year's spores. Fungicide has a role against Phomopsis on emerging growth in a wet spring on a valued planting, but it does not substitute for pruning out the dead tissue.
Will the brown tips green up again?
No. Dead foliage on juniper and arborvitae stays dead and does not recolor. What you are looking for is healthy new growth beyond and around the pruned areas. If a plant is producing good new growth, it is recovering even though the old damage remains visible.
One plant in my hedge is mostly brown. Can it be saved?
Rarely into an acceptable screen. These species do not reliably regrow from bare old wood, so even a plant that survives may keep a permanent gap. Replacing the individual plant inside an otherwise healthy hedge is usually the better outcome, matched to the same cultivar so the run looks consistent.
