Invasives can sneak into any garden

Three of the most prolific invasive plants in Connecticut – Japanese barberry, Oriental bittersweet, and multiflora rose – can sneak into any garden, making it very important to learn how to identify and manage them.

Learn to identify Connecticut’s invasives by studying the information at the Connecticut Invasive Plant Working Group, seeking the advice of gardener or garden coach experienced in identifying the most prolific garden invasives in your area, and/or taking small samples to a trusted, local garden center for identification.

During this time of year, when invasive shrubs and vines are leafing out, I search for young Japanese barberry, Oriental bittersweet, and multiflora rose sprouting in and around bird-popular shrubs and trees. Birds eat the berries produced by more mature specimens of these invasives growing on neighboring properties, then spread undigested seeds via droppings. So … just below where birds like to roost is a good place to watch for emerging invasives.

What I found this week under a bird-popular winterberry shrub growing at the edge of our driveway is a perfect example.

Invasive Japanese barberry, Oriental bittersweet, and multiflora rose sprouted under a winterberry shrub

Invasive Japanese barberry, Oriental bittersweet, and multiflora rose sprouted under a winterberry shrub

You might not expect this to be the scene of an invasion … but it was. Among young winterberry shoots, different types of sedum, violets, an iris, ornamental grasses, and a dandelion grew three very unwanted plants.

The young Japanese barberry caught my eye first.

Young Japanese barberry

Young Japanese barberry

Then a closer look revealed a multiflora rose and young Oriental bittersweet shoots.

Young Oriental bittersweet and multiflora rose

Young Oriental bittersweet and multiflora rose

Without a keen eye and knowing what is what, it’s easy to pass over the bittersweet as emerging winterberry shoots, but closer examination reveals the difference in the leaves.

Now that I’ve found the three invasives growing under this winterberry, I will recheck the area throughout the growing season to be sure no other bird-dropped seeds have sprouted.

Once one becomes adept in how these three young invasives look, finding them becomes easier. Familiarize yourself with the look of young Japanese barberry; note the thorny stems. Moreover, the interior roots are yellow-green.

Young Japanese barberry, Oriental bittersweet, and multiflora rose pulled  and left to dry and die.

Young Japanese barberry, Oriental bittersweet, and multiflora rose pulled and left to dry and die.

The multiflora rose has a typical-looking rose leaf and the stems sport classic rose thorns.

Oriental bittersweet can be sneaky, but once you familiarize yourself with the various stages of growth, you’ll become quite adept at -spotting this invasive vine. Leaves on young vines are light green, the stems – with leaves at the very end – usually stand straight up reaching toward the light and the roots are orange.

Do not put these plants in the compost pile. Leave them on a hot surface to dry and die before disposing of them in the trash.

By finding these three invasives early, you can usually pull them out of the ground with roots intact. Once they become larger it becomes more difficult to get all the roots out of the ground, which allows re-sprouting. Still, any location where one of these young invasives has been found and pulled must be re-visited through the growing season to check for re-growth which, of course, requires re-pulling and continued re-checking.

Why bother with all this? All three are highly invasive and crowd out other, often native, vegetation. Japanese barberry is particularly noxious and creates a perfect habitat for disease-bearing ticks. Oriental bittersweet is a vine that will wind around and smother anything. Multiflora rose is thorny and not the nicest looking rose,  grows quickly, and crowds out other vegetation. Plus, these invasives are much easier to eradicate when young, with small root systems. Once any of the three become established they are a whole lot more difficult to eradicate.

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Managing Japanese Barberry

Managing Japanese barberry is a royal pain, but it may be one of the best health protective landscape management tasks one can undertake.

Those who have followed this blog over the years likely remember many of the posts on how Japanese barberry is taking over many areas of Connecticut’s woodlands and how Japanese barberry creates a perfect environment for ticks and mice.

It’s hard to find a Connecticut resident who has not had a bout of Lyme disease or another tick-related disease. Now, there’s another disease – Powassan virus – linked to black-legged ticks. While no human cases of Powassan virus have yet been identified in Connectucut, if it is transmitted by black-legged ticks it’s only a matter of time.

The increasing disease risk from black-legged ticks makes controlling Japanese barberry even more important. I outlined various control methods in previous posts – linked above.


Serious stands of Japanese barberry, like the one above, may require heavy equipment, like a brush hog, followed by repeated control methods of regrowth. But regular control is the only way to eradicate Japanese barberry from a property.

A property walk now, when Japanese barberry is one of the only leafed-out under story shrubs, identifies how much and where this invasive shrub is growing. If you are fortunate, as in my case, to have little Japanese barberry invasion on your acreage you can use my control method – pulling out young, and still small, shoots and leaving them on a nearby rock or fallen tree to dehydrate and die.

small Japanese barberry

small Japanese barberry

This is the method I used with yesterday’s finds in the woods.

Japanese barberry roots and stem

Japanese barberry roots and stem

But, this area needs to be revisited one or two times throughout the growing season, and definitely in early autumn, to watch for and control re-sprouts from any left-over roots in the ground. Japanese barberry is known to re-sprout with vengeance. Subsequent Japanese barberry walks help identify any shrubs/sprouts previously missed.

If Japanese barberry is growing anywhere on your property – but particularly anywhere near your house – do yourself, your family, and Connecticut’s woodlands a huge service … remove it and control its return.


More on tick-borne diseases at A Way to Garden

The Connecticut Agricultural Experiment Station Japanese Barberry Control Methods


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How to dispose invasive plants

If my latest Winter Review post, Are you invasive species savvy? did not offer ample links for learning about Connecticut’s invasive plants, check this guide. Once you can identify invasive plants, and likely have learned your landscape contains at least one, it’s time to learn how to properly dispose invasive plants.

Connecticut’s DEEP and the University of Connecticut developed Guidelines for Disposal of Terrestrial Invasive Plants. Not all invasive plants are treated equally when it comes to disposal. The guidelines noted above are the most comprehensive I’ve found to date and provide valuable information on the proper disposal of terrestrial invasive plants.

Based on these guidelines and my own experience, these are the most important rules to follow when removing and disposing of invasive plants from a home landscape.

Rule #1: DON’T ADD INVASIVE PLANTS TO YOUR COMPOST PILE! This refers to the compost you intend to spread back into planting beds. Home compost piles often don’t get hot enough to destroy all seeds/roots. When spreading home compost to planting beds you don’t want to also spread still viable seeds/roots from any invasive plant.

Rule #2: R-read Rule #1.

Rule #3: Read the guidelines, print them, bookmark the link, and refer to the guidelines regularly.

Rule #4: Repeat Rule #3.

As an Organic Land Care Professional caring for home landscapes, I do not advocate the use of chemicals for control of invasive plants. Instead, I suggest vigilant observation for invasive species, followed by cutting, pulling, smothering, and/or burning, followed by vigilant observation and re-cutting, re-pulling, re-smothering, and/or re-burning as needed.

OLYMPUS DIGITAL CAMERA Dealing with invasive plants is not sexy, but it is an oh-so necessary part of gardening in today’s world.

Catching invasive plants when they are still young, removing them, and regularly rechecking for re-sprouts, is the best control method and the easiest way to prevent invasive plants from taking hold. I do invasive plant patrols on our nearly three acres of home gardens and woods in early spring, late spring/early summer, mid-summer, late-summer, and before a killing frost. These patrols have proved to be as important as weeding in my cultivated beds.


For small, invasive woody shrubs, vines and trees, I use the pull-out-all-roots and leave-to-dry method. The key is in getting all the roots. I often leave the pulled plant to dry atop a fallen tree , then target the areas where invasives were found for continued re-checking for new sprouts. This is particularly important for Japanese barberry, as it aggressively regenerates from the slightest piece of root left in the soil.

OLYMPUS DIGITAL CAMERA When I spot a large number of newly sprouted invasive plants – think Oriental bittersweet seedlings that sprout each spring under trees after birds have deposited partially digested seeds during winter roosting visits to the tree’s upper branches – I collect pulled seedlings in a plastic bag (I reuse large plastic bags from prior mulch, compost, or soil amendment purchases). Letting bagged seedlings bake in the sun for a week or so kills seeds/roots then the bags go into the trash.

This is my preferred disposal method for Japanese Stilt Grass seedlings and plants (left photo), bittersweet seedlings, garlic mustard, and any small weed in flower.

After weeding out young invasives – or any weeds – be sure to follow the standard good-gardening practice of covering exposed/disturbed soil with some sort of mulch.

Larger invasive plants, such as bittersweet vines that have climbed into trees, can be cut to prevent further growth, leaving cut remains on site to dry. But cut trunks/stems must be monitored for re-growth. And … if the invasive has produced flowers or seeds, the area must be regularly checked for newly sprouted seedlings. Non-flowering, non-seeding woody plant material can be chipped, left in place,  or used to create a brush pile as habitat for woodland birds and creatures.

Japanese barberry requires repeated monitoring and managing of regrowth. This video shows how torching is used for Japanese Barberry control, but this method requires specific precautions and is not recommended for everyone.


Courtesy of the Univ. of CT Extension System, CT Agricultural Experiment Station

The proper management and disposal of invasive plant material is best determined by the location, age, size, flowering status, and reproductive ability of each invasive. To keep invasive plants from spreading and overtaking your landscape you need to make monitoring and control a regular gardening task … just like weeding.

Invasive plant control can seem a daunting task, but keep at it … the more diligent you are in controlling invasive plants in your landscape the less time you will ultimately need to spend controlling them.

February 23 to 28, 2014 is National Invasive Species Awareness Week … take this opportunity to learn more about invasive species in your area.

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