Among the challenges of advocating native plants over alien invasives is that many invasive plants are commonly sold in nurseries, and have been bred to accentuate highly valued characteristics, which results in dozens of cultivars. One such invasive plant is Japanese Barberry (Berberis thunbergii). This small shrub is characterized by a rounded habit, sharp thorns covering its branches, and very attractive red/burgundy foliage that becomes brighter red in fall. Japanese barberry is very heat and drought tolerant. Proven Winners has introduced more than a handful of cultivars ranging from upright pillar forms to several with bright yellow/lime green colored foliage, and now even some that don’t have the painfully sharp thorns. It’s easy to see why this shrub is a top seller.
However, it is not without it’s problems. It seeds freely from berries produced in the fall, and also spreads by underground runners. It can form dense colonies within a few years and can choke out native plants that are important to wildlife. Now, there is some evidence starting to emerge that Japanese barberry may promote the prevalence of Lyme disease. Click here for an article on that subject. Gardeners should always be aware of what they’re planting, as many nurseries sadly do not refrain from pushing invasive plants.