Japanese barberry (Berberis thunbergii)

Japanese barberry branch with red berries and maroon leaves

 
 

Japanese barberry is a shrub that can form dense cover in forests and open areas. The spines on Japanese barberry plants can make it difficult to move through patches.

Description

Appearance

Japanese Barberry is a small, compact, spiny shrub. It can grow 3-6 feet tall with slightly curving branches.

Leaves and Stem

Japanese barberry leaves are small, rounded, and smooth. Leaves are arranged in clusters above single spines and appear early in the spring.

Flowers

Flowers are yellow and are attached to the stem in clusters of 2-4 blossoms or as a single blossom. Flowers bloom in May.

Seeds and Fruits

Fruits are small, bright red, egg-shaped berries found in clusters or alone. Fruits mature in August and stay on the shrub through winter. Seeds are dispersed when birds eat the berries.

Roots

Japanese barberry spreads vegetatively through horizontal lower branches that root freely when they contact the soil.

Biology

Japanese barberry is a perennial shrub that reproduces by seed. Seeds are spread when birds eat the fruit. It invades oak woodlands and oak savanna and prefers well-drained soils. Deer do not graze on it.

Origin and Spread

Japanese barberry is native to Japan. It was introduced to North America as ornamental plant, as a living fence, and for erosion control. In Minnesota, it has spread from where it was planted to natural areas.

Refer to EDDMapS Distribution Maps for current distribution.

Don't be fooled by these look-alikes

  • Common barberry, Berberis vulgaris (invasive) – Common barberry leaves are toothed while Japanese barberry leaves have smooth edges. Common barberry spines have three prongs while Japanese barberry spines have one point. Common barberry flowers can be in clusters of 10-20 flowers while Japanese flowers clusters have 1-4 flowers.
  • Prickly ash, Zanthoxylum americanum (native) – Prickly ash has compound leaves (divided into 5-11 leaflets) and its thorns are in pairs along the branch.
 
Regulatory Classification

Japanese barberry and the following cultivars of Japanese barberry are Minnesota Department of Agriculture Restricted Noxious Weeds meaning it is illegal to import, sell, or transport them. Japanese barberry cultivars that cannot be sold in Minnesota: 'Anderson' (Lustre Green™); 'Angel Wings'; 'Antares'; 'Bailgreen' (Jade Carousel®);'Bailone' (Ruby Carousel®); 'Bailsel' (Golden Carousel® -B.koreana × B.thunbergiihybrid); 'Bailtwo' (Burgundy Carousel®); B. thunbergii ;var. atropurpurea; 'Crimson Velvet'; 'Erecta'; 'Gold Ring'; 'Inermis'; 'JN Redleaf' (Ruby Jewel™); 'JN Variegated' (Stardust™); 'Kelleris'; 'Kobold'; 'Marshall Upright'; 'Monomb' (Cherry Bomb™); 'Painter's Palette'; 'Pow Wow'; 'Red Rocket'; 'Rose Glow'; 'Silver Mile'; 'Sparkle'; 'Tara' (Emerald Carousel® - B. koreanax B. thunbergiihybrid); Wild Type (parent species – green barberry)

Threat to Minnesota
  • It can form impenetrable, thorny thickets. Once established, its prolific spreading shades out native plants.
  • Japanese barberry can alter soil properties and change soil microbial communities.
  • Researchers in the eastern United States are finding that forests with dense Japanese barberry harbor more black legged ticks (deer ticks) than those without Japanese barberry. It is thought that the Japanese barberry plants cause a humid microclimate that is favorable for the ticks. Black legged ticks can carry Lyme disease and other tick-borne diseases so there are concerns for human health impacts from Japanese barberry.
  • Japanese barberry can hybridize with non-native common barberry. Common barberry is a host of black stem rust, which can cause severe losses to grain crops. There was a national common barberry eradication project from 1918-1990. Japanese barberry does not host the rust. There is concern that hybrids of Japanese barberry and common barberry would be able to host the rust.
What you should do

One way that invasive plant seeds and fragments can spread is in soil.  Sometimes plants are planted purposefully.  You can prevent the spread of invasive plants.

PlayCleanGo: Stop Invasive Species in Your Tracks

  • REMOVE plants, animals & mud from boots, gear, pets & vehicle.
  • CLEAN your gear before entering & leaving the recreation site.
  • STAY on designated roads & trails.
  • PLANT non-invasive species.
Native Substitutes
 
Control Methods

Mechanical control can be done by digging out the plant with a shovel or hand pulling small plants.

Herbicide control can be done using systemic herbicides, which are taken up by plants and move within the plant, killing leaves, stems, and roots. Cut plants will resprout if the stump is not treated with herbicide after cutting. Immediately after cutting (within 2 hours), apply an herbicide containing triclopyr (Garlon 3A/Vastlan, Garlon 4, or other brush killers with triclopyr) or glyphosate (Roundup) to the cut stump to prevent re-sprouting. Always follow label instructions for herbicides. Herbicides can be applied to cut stumps with a paintbrush, wick applicator such as a dauber or "buckthorn blaster," or a low volume sprayer.

In cases where more than a few plants are treated, add an indicator dye (available where pesticides are sold), such as Mark-It Blue, to the herbicide to mark which cut stumps you have sprayed.

For basal stem treatment, a method that applies chemical through the bark, low volume spray applications can be made with Garlon 4, Pathfinder II and similar oil-based products. This application method uses triclopyr ester mixed with an oil diluent (i.e. Bark Oil Blue, kerosene) applied directly to the bark of Japanese barberry from the root collar up about 12-18 inches. An ultra-low volume spray wand should be used to minimize herbicide use and reduce the potential for non-target injury.

If you need to remove plants from your property, please review the Minnesota Department of Agriculture's Guide to Removal and Disposal of Noxious Weeds in Minnesota or contact your local County Agricultural Inspector for disposal suggestions in your county.

Reporting

Report new occurrences by submitting a report through EDDMapS Midwest, emailing Arrest The Pest, calling Arrest the Pest (1-888-545-6684), or contacting your local county agricultural inspector

Resources