The Hidden Tick Magnet in Your Yard: Japanese Barberry

Do you feel that you are easily ticked off, your anger resting atop a gasoline-fueled, combustible pile of kindling? Sometimes, the source of one’s ire can be surprising – and for anyone afflicted with ticks, they’re probably surprised that this plant is the bearer of bad news. 

The Japanese barberry is not an ugly plant by any means; it has an innocuous quality with its dense, thorny thickets and the spiky little berries that birds seem to adore. But ticks are serious business as transmitters of the deadly Lyme disease, and as the statistics show: the greater amount of Japanese barberry growing on a property, the greater amount of Lyme disease-ridden ticks you are likely to encounter.

What Is Japanese Barberry?

Japanese barberry (Berberis thunbergii), a deciduous shrub native to Japan and Eastern Asia, was introduced to the US to replace the common barberry (Berberis vulgaris). Efforts to eradicate the common barberry – an alternate host to black stem rust, a fungus that devastates wheat crops – were successful in the eastern half of the United States. Yet, it was with a foolish notion that its pernicious cousin, the Japanese barberry, was let loose. 

Japanese barberry invades when its seeds, dispersed by birds, intrude into unmanaged natural areas. There, it forms dense thickets that outcompete and displace native vegetation.

Why Do Ticks Proliferate in Japanese Barberries? 

Ticks are drawn to Japanese barberry for a number of reasons. The undersides of the thorny foliage are damp and moist, forming the ideal microenvironment for black leg ticks (the primary transmitters of Lyme) to proliferate. Low light levels and high humidity combine to create prime territory for ticks and other unsavory creatures that carry disease.

“To a tick, a barberry is a skyscraper; it’s got this huge protective cover that provides this little microclimate on the forest floor,” says Sarah Wurzbacher, a forester with Penn State Extension

White-footed mice, known to harbor and transmit Lyme disease, are another culprit that seek the damp foliage for shelter and cover. In essence, barberry bushes are damp nests of bacteria, the lightning rod for all things disease-ridden and pestilent. Unchecked by predators or disease, it aggrandizes space meant for native species. 

Scientific studies confirm this link. Research has found that areas with Japanese barberry can harbor up to eight times more ticks than areas without it. The results are telling: researchers at Trinity College collected 55 blacklegged ticks: 38 in the full barberry habitat; 11 in the partial barberry habitat; and 4 in the habitat without barberry. 

How to Identify Japanese Barberry

To identify Japanese barberry, look for spatula-shaped leaves clustering around arching stems. While Japanese barberry can mimic native barberries, the invasive species tends to grow more aggressively and form more belligerent clusters.

• Leaves: Small, distinctly spoon-shaped, often a deep red, maroon, or chartreuse depending on the variety; most follow a pattern of green leaves in the summer followed by reddish orange foliage. They grow in clusters along the stem.

• Berries: Bright red and oblong, appearing in fall and often persisting into winter. Birds love these, which helps spread the seeds.

• Thorns: Tiny, sharp, and plentiful. Each stem can have multiple thorns. 

• Growth Pattern: Japanese barberry often forms dense, impenetrable thickets that make walking through or near them difficult.

Destroying Japanese Barberry Safely

Removing Japanese barberry is crucial for maintaining the delicate balance of nature. In this case, they are the enemy that perform a hostile takeover, to the detriment of everyone around them – the party never stops, spiraling out of control until gardeners are ready to declare war on those pestilences. Small or medium-sized barberry bushes can be pulled or dug out, although multiple efforts may be required. 

1. Manual Removal: Wear gloves and protective clothing to avoid thorns. Uproot the shrubs entirely if possible. Smaller plants can sometimes be pulled by hand, but larger shrubs may require digging tools.

2. Mulching and Disposal: Do not compost barberry in your backyard compost – it can sprout and continue spreading. Bag it and dispose of it according to local guidelines.

3. Herbicides: In areas where removal isn’t feasible, selective herbicides can be used. Apply carefully following the manufacturer’s instructions to avoid damaging surrounding plants.

4. Monitor and Repeat: This plant is a tenacious fighter and does not give up easily. Japanese barberry can regrow from small root fragments, so you’ll need to monitor the area and remove new sprouts promptly.

While it might feel like an uphill battle, the removal of even a few stubborn shrubs from high-traffic areas like yard edges, trails, or play areas can significantly curtail tick populations.

Alternatives to Japanese Barberry

On the surface, Japanese barberry hits the plant resume pretty well – it is unpalatable to deer, resistant, and barely needs attention. But those qualities belie an insidious nature, making it a haven for ticks. Native shrubs such as winterberry, mountain laurel, and oak leaf hydrangea are preferred over the disastrous barberry. Raised garden beds make it easier to grow a variety of plants and remove those you don’t want.