Is This Invasive Shrub Could Causing a Tick Control Crisis?

A Japanese shrub is overwhelming native shrubbery all across America – but is this voracious weed also increasing the danger of Lyme disease?

America is under assault from the Far East. At first was a voracious form of stink bug. Now it’s a tough and hardy type of spiny, red-berried shrub.

Much like the gypsy moth caterpillar, the invasive shrub Japanese barberry (Berberis thunbergii) was first brought to American shores during the Victorian era, as a shipment of seeds to Boston’s Arnold Arboretum.

Initially, people welcomed the shrub, as its bright berries were decorative, and it grew well in the shade of tall buildings. Drought resistant, the plant also thrived anywhere from arid desert to damp and hostile swampland.

But within a few decades, people realized that the resilient nature of the shrub was as much a curse as a blessing. It began muscling out native shrubs –and damaging the delicate ecostructure that they nurtured.

One repercussion of this that scientists are only beginning to understand is the link between Japanese barberry and Lyme disease. Researchers at the Connecticut Agricultural Experiment Station (CAES) have discovered that reported cases of Lyme disease are significantly higher in areas with a high density of Berberis thunbergii than those without.

Two factors are responsible for this – firstly, the fact that deer don’t have a taste for barberry.

"Deer eat everything but barberry, and because they don’t eat barberry, they’re weeding out forests. They’re helping promote the shrub,” reports chief scientist for the Department of Forestry and Horticulture Jeff Ward.

Deer are also the primary vector for ixodes scapularis – the blacklegged deer tick that spreads Lyme disease through tick bites. Further contributing to the Lyme disease crisis, when the ticks deer carry drop off their hosts, they find a perfect shelter within the leaves of Berberis thunbergii.

Ticks require considerable humidity to thrive – which is why they’re rarer in hot states like Arizona and New Mexico. But because Japanese barberry has a denser foliage than native plants, ticks enjoy a higher humidity beneath their shade – and that gives them an opportunity to spread wider, and in larger numbers than ever before.

And as a result? The incident of tick bites goes up – and so does the number of reported Lyme disease infections.

As a homeowner, it’s time to take stock of your plants and shrubs. Do you have Japanese barberry growing on your lawn or landscape? If you do – it could be placing you and your family at a higher risk of tick bites and Lyme disease.

Protect yourself by contacting a tree and lawn care specialist, like the tick control experts from Aspenn Environmental Services. They’ll be able to help identify whether or not you have the aggressive shrub on your property – and give you options for dealing with the ticks they often harbor.

This could include a recommendation to remove the offending shrubs – or just to eliminate ticks and tick eggs from with a tick spray treatment. A yard spray for ticks can help get rid of ticks from your property – and help reduce the risk of tick bites all year round.