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The native, Northern Fly Honeysuckle looks much more delicate, has pendulous flowers, football-shaped berries, and a white center to their stem. Photo by Emily Stone.

The cool, damp air smelled delicious as I ambled up the gravel road. I’ve been up and down ladders and scaffolding for exhibit construction lately, and so I haven’t had the energy for big bike rides in the afternoon. That’s fine. I will still be able to bike once the mosquitoes hatch, but I won’t be able to walk slowly without a head net.  

When the blossoms of a honeysuckle bush caught my eye, I was even happier for my slow pace. I stopped to admire the prismatic raindrops caught under each flower’s chin.  

Northern Fly Honeysuckle’s pale yellow flowers dangle in delicate pairs. Their fluted shape with a long nectar tube is a clue that hummingbirds love them. The flowers don’t last long, though, and are soon replaced by two green fruits, shaped a little bit like tiny footballs, and joined at their pointy ends. The berries ripen to a vibrant shade of red, which really pops in the cool shade of the forest. Birds, especially robins and cardinals, love them.  

The week prior, I’d been in Duluth, getting some fresh air on one of the many creek side trails before buying some last minute items for exhibit construction. It was a cool day, but sunny, and was starting to look like spring. Dandelions dotted the grassy areas, and in the woods, there were a lot of little green leaves right at eye-level.

My friend commented on how nice it was to see the green. I tried to agree, but couldn’t quite muster excitement. These leaves – unfurled a week or two before much else – belong to a non-local honeysuckle who evolved with the spring schedule of an entirely different continent!   I grew up with this variety, Tartarian honeysuckle (Lonicera tatarica), in my backyard, and spent many days gathering the round red and orange berries to use as pretend food in my playhouse. Now I know that this childhood friend can be quite invasive.

A native of China, Manchuria and Korea, they left behind their native predators when arriving here, and tend to run rampant in our vacant lots and deciduous woods, creating impenetrable thickets in the worst cases. They joined several other species of non-local honeysuckles who all share the same invasive tendencies.  

While native and non-local honeysuckles share some characteristics, it’s not hard to tell them apart. All have pairs of white, pink or yellow flowers with a nectar tube and fluted petals. All have paired leaves (“opposite arrangement” to botanists,) and all have red or orange berries. The invasive honeysuckles get much bigger and bushier, though, and some species have pointed, serrated, or fuzzy leaves. Their abundant flowers are held upright. Plus, the berries on invasive honeysuckles are round instead of football-shaped.  

The surest way to distinguish the honeysuckles in any season is to crack open a twig and look at the pith. The pith is the soft, spongy tissue in the center of the stem. In native honeysuckles the pith is pure and white. In non-local species, the pith is either brown or hollow.  

Like many invasive species, the Eurasian species of honeysuckles tend to crowd out native plants and provide a lower quality food source to animals. As birds and mammals eat the berries and disperse the seeds, non-local honeysuckles quickly invade open woodlands, old fields, and other disturbed sites, and form a dense thicket that prevents other native plants and trees from growing.  The northern fly honeysuckle is one that gets pushed out by their cousin.  

With lower diversity, the wildlife cover is reduced, and cardinal nests in particular are less successful, despite the thicket. Fewer insects in the non-local honeysuckle reduce food sources for many warblers and flycatchers. Although abundant, the berries contain less fat and energy than their native counterparts. When cedar waxwings eat too many red honeysuckle berries, the pigment tints their normally yellow tail tip and turns it orange. On the flip side, male cardinals who eat non-local honeysuckle berries may be brighter red, even though they are less fit. Females have a harder time determining the healthiest mates.  

As you pass yard after yard surrounded by Eurasian honeysuckle hedges in full bloom, it’s easy to imagine how this invader got here. They were first introduced into North America as an ornamental in 1752! Many invasives got their start in the nursery trade, either as the main attraction or a hitchhiker.   As I continued up the gravel road with my eyes tuned for honeysuckle, I began to notice more and more of the delicate native, Lonicera canadensis. They may not be as showy as the other kinds we imported for hedges, but they have a subtle beauty I adore. Even with the exhibit finished, I think I’ll keep walking slowly until the buzzing hordes appear!      

Tips to reduce the spread of invasive species:   Prevention is worth an ounce of cure, so they say, and it is definitely easier to keep the weeds out than to get rid of them once they’re here. Do a little research before you buy new plants from a nursery, and try to choose to plant native species. Use those boot brushes at trailheads to make sure that you aren’t carrying seeds from trail to trail. Clean your equipment between locations, especially if you know that you’ve just been working in a place that has non-local species.  

If you discover an invasive species on your property or public land, contact the Northwoods Cooperative Weed Management Area (NCWMA) by calling 715-373-6167 or emailing info@northwoodscwma.org. Various local land management agencies can help you set up a plan to control the non-local species and create better habitat on your land.    

Note: Portions of this article are reprinted from 2023.