Eliminating buckthorn will improve the habitat on any property
Eradicating buckthorn is impossible. However, by taking a serious whack at it, the native plants will sometimes take advantage of the temporary demise of the buckthorn.
Buckthorn is one of the few really nasty, invasive exotic plants that affect forests. The species will gradually overtake the entire understory, unless conditions are particularly shady or dry. It’s commonly seen in wetland margins and under powerlines. Many people mistakenly call it tag alder. It’s hard to believe that one could long for tag alder, but it beats the heck out of buckthorn.
Buckthorn casts dense shade. Most native herbs and shrubs lose out. Tree regeneration fails. The structure and fruits may provide benefits to a few wildlife species, but nothing as rich as the native flora.
Actually, there are three species of buckthorn common to Michigan. Two are exotics. One is native. Glossy buckthorn (Frangula alnus, formerly R. frangula) and common buckthorn (Rhamnus cathartica) are the exotic invasives. Glossy buckthorn tends to grow more in and around wetlands. Common buckthorn has a bit stronger preference for a variety upland soils and usually has lots of thorns. Neither shrub does particularly well on dry sand.
Alder-leafed buckthorn (R. alnifolia) is the native, but it’s not nearly so common as the other two. It also prefers wetlands but the leaves are different from its evil cousins, looking more like alder leaves. The native buckthorn seldom grows more than three feet tall and is much less “bushy”. There only a few flowers / fruits per cluster, unlike the robust exotics.
It’s good to know how to identify these noxious plants. The leaves are rather plain-looking and you can use that ID feature, sometimes. Note the number of main veins. If you scrape the stems, you’ll notice that the inner bark is often bright yellow and smells a bit like squashed ladybugs. The flowers and fruits are distinctive. They grow in small clusters and the fruit turns from red to black. Common buckthorn has four petals, glossy buckthorn five. Some folks mistake them for cherries or wild plums. I once had a neighbor challenge my removal of all that “cherry”.
Eradicating buckthorn is impossible. However, by taking a serious whack at it, the native plants will sometimes take advantage of the temporary demise of the buckthorn. During the winter, I spend a fair amount of quality machete time. Chopping buckthorn would probably be more effective around mid-June, but that’s also when the mosquitoes are really bad and the wetlands are wet. Winter is more pleasant.
Come spring, the buckthorn stumps sprout back vigorously. It’s amazing. No wonder the native plants don’t stand a chance. However, after that thick flush of growth forms a nearly complete canopy of leaves, it’s also the perfect surface to collect herbicide. I generally spray in late September or early October. By then, many of the native herbs have gone dormant. The collateral damage from the herbicide is minimized. Sometimes, I have to return to an area to spot spray the next season. Buckthorn is a tough customer.
Alternatively, stump herbicide can be immediately applied to fresh-cut buckthorn during the growing season. This is tedious but effective. A number of applicators are available to make the job a bit easier.
There is no easy way to get rid of buckthorn. All require physical work and persistence. The visual quality of removing buckthorn is immediate (and satisfying). The woods at least appear a bit more native without the nearly impenetrable stands of buckthorn. More rewarding is watching the native vegetation respond over the next few years. Given a sporting chance, quite a few native species will increase their presence. But this is a case where human intervention is needed with every tool at our disposal.