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Extension > Yard and Garden News > Japanese Barberry Added to Minnesota's Noxious Weed List

Monday, February 29, 2016

Japanese Barberry Added to Minnesota's Noxious Weed List


Kathy Zuzek, UMN Extension Educator

Barberry fruit & seed are eaten & dispersed
 by birds.
Photo: K. Zuzek
Japanese barberry (Berberis thunbergii) is native to Japan and Korea and was introduced into the United in the late 1800s.  Although they provide beauty in gardens and landscapes, barberries have become naturalized and invasive in 30 states in the eastern U.S. including Minnesota.  The fruit are an attractive food to birds who disperse seed into native areas.  Barberries establish in the undergrowth of forested areas where they often form thickets and outcompete and displace native plants.  84 incidences of barberries in native ecosystems have been reported in Minnesota.  67 of the 84 reports are from the southeast quadrant of the state.

MN counties where Japanese barberry
has been found in native ecosystems,
Map source: EDDMapS
To manage invasiveness, Japanese barberry was added to Minnesota’s noxious weed list in 2015 as a specially regulated plant.  Specially regulated plants have a species-specific management plan developed by Minnesota’s Commissioner of Agriculture.  In the case of Japanese barberries, a three year phase-out of the 25 seediest cultivars (listed in the table below) was implemented in Minnesota on January 1, 2015 by the Minnesota Department of Agriculture.   By 2018, these cultivars will no longer be marketed in Minnesota because it will be illegal to sell, propagate, or transport those 25 cultivars.  More information on barberry and its regulation can be found here

What can Minnesota gardeners do to help prevent additional barberry invasiveness?  Here are some suggestions:

If you grow any of the barberry cultivars listed in the chart, consider removing these plants and replacing them with alternative plants.  Other barberries are available that produce much fewer seed. But even barberries with lower levels of seediness can contribute to barberry invasiveness. So better yet, replace your barberries with a different shrub species.   Alternative species with brightly colored foliage or fruit include ninebark, weigela, chokeberry, bayberry, winterberry, Bailey select purpleleaf hazelnut, redosier and Tatarian dogwoods, American cranberrybush, and arrowwood viburnum.
A thicket of Japanese barberry in a
native woodland.
Photo: L.J. Mehrhoff,
Univ. of CT, bugwood.org
Consider removing spent flower clusters on barberries in the landscape to prevent seed development. This is not a fun job given that barberries are thorny plants.  But removal of individual flower clusters on smaller barberry cultivars might be a possibility.  On larger barberry cultivars, a renovation pruning immediately following flowering that temporarily removes the entire plant canopy may be the only practical way to eliminate fruit. 




The 25 most heavy-seeding Japanese barberry cultivars from University of Connecticut research
Cultivar
Av. # of Fruit/Plant
‘Angel Wings’
1847
‘Antares’
620
B. thunbergii (wild type)
1105
B. thunbergii var. atropurpurea
1045
Burgundy Carousel®
1377
Cherry Bomb™
1225
‘Crimson Velvet’
6675
Emerald Carousel®
9926
‘Erecta’
2912
‘Gold Ring’
954
Golden Carousel®
681
‘Inermis’
1152
Jade Carousel®
2267
‘Kelleris’
855
‘Kobold’
842
Lustre Green™
4257
‘Marshall Upright’
3249
‘Painter’s Palette’
1177
‘Pow Wow’
1004
‘Red Rocket’
1332
‘Rose Glow’
939
Ruby Carousel®
1011
Ruby Jewel™
998
‘Silver Mile’
638
‘Sparkle’
5543
Stardust™
768

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