We’re Seeing a Lot of Euonymus Scale: Check Your Plants

What Is Euonymus Scale?

Euonymus scale (Unaspis euonymi) is a serious insect pest that affects a wide range of ornamental plants, with a particular preference for Euonymus shrubs and groundcovers. This pest is well established in southern New Hampshire, and if left untreated, it can cause significant damage to landscapes—often resulting in plant decline or death.

How to Spot It Early

Early identification is key to managing Euonymus scale effectively. The first signs typically include yellowing leaves, stippled foliage, and premature leaf drop. Closer inspection may reveal small brown, oyster-shell-shaped scales along stems and twigs (these are adult females), or flat, white scales on the undersides of leaves (often immature males or crawler-stage insects). As infestations progress, entire branches may die back from the bottom up. Using a hand lens or gently scraping the bark can help confirm a scale infestation—if the scales flake off like tiny armored plates, it’s likely Euonymus scale.

Be On The Lookout !

Euonymus scale is a destructive, sap-sucking insect that weakens shrubs and can cause yellowing, dieback, and plant death. Females appear as brown, oyster-shaped scales on stems; smaller white males cluster on the undersides of leaves during active infestations.

When It Spreads in New Hampshire

In southern New Hampshire, this pest produces two generations per year, with crawler stages emerging in early June and again in late July. The crawler phase is when the insects are most mobile and likely to spread to other plants. While Euonymus is the primary host, heavy infestations may also move onto nearby boxwood, holly, or pachysandra, making early action especially important in mixed plantings.

Should You Remove the Plant?

For plants with mild infestations, targeted pruning and horticultural oil treatments during the crawler stage can be effective, especially when combined with proper watering and fertilization. Encouraging natural predators like lady beetles and parasitic wasps can also help keep populations in check. However, if the plant is severely infested, appears stunted or disfigured, or continues to decline over multiple seasons, removal is often the best long-term option—especially if other nearby Euonymus are at risk.

Local Impact in Southern New Hampshire

Euonymus scale is a recurring problem in ornamental landscapes throughout the Seacoast region, especially in sheltered areas within larger shrubs or around buildings. Landscapers and homeowners alike should monitor Euonymus plants regularly, particularly in June and late July, and consider replacing heavily infested shrubs with scale-resistant alternatives.

Help from Seacoast Gardener

If you’re unsure whether a shrub can be saved—or if it’s time to let it go—Seacoast Gardener is here to help. We offer expert plant health assessments, pruning, and full shrub replacement services throughout southern New Hampshire. Whether you want to salvage a favorite plant or start fresh with a healthier landscape, our team brings deep horticultural knowledge and hands-on care to every yard we maintain.

📞 (603) 770-5072 | 🌐 www.seacoastgardener.com