Monday, November 9, 2009

Autumn Olive

For those of you who do not know what autumn olive is, here's a photo:

I too used to be blissfully ignorant of this vile shrub, but I had to go and get involved with the DNR's Stewardship program. There you learn that we are surrounded by nasty alien species that are choking the life out of our native habitats. Now it is difficult for me to go out without seeing what shouldn't be growing, although it certainly makes me appreciate an area where native plants are still holding on (like Teahen Prairie, where I helped with moth collecting).

We all are familiar with Dutch Elm disease (or at least I hope we are!). Then there's the Emerald Ash Borer. In between came American Chestnut blight (if you want to read about the chestnuts, grab a copy of Barbara Kingsolver's Prodigal Summer). These were actual pests, bugs and nasties that ate (or are eating) our native flora, with startling and obvious consequences--lots of dead trees. But more insidious than these are the non-native flora, the trees and shrubs and flowers that grow in abundance and give the appearance that all is well (since it all looks green and pretty) when in fact nothing is as it should be.

We are plagued by non-native plants: black locust, glossy buckthorn, Asian bittersweet, spotted knapweed.... The list goes on and on. Areas that saw the greatest disturbance--logged then farmed or pastured for years--generally have the biggest problem with invasives. Southeast Michigan is filthy with them, and our property is no exception.

Below is a shot of a "grove" of autumn olive. As you can see it is a dense shrub and when it grows like this it blocks out the sun and keeps other plants from growing.

Here is a description from the Tennessee Exotic Plant Management Manual: "Autumn olive was introduced into the United States in 1830 from China and Japan. It has been actively promoted by state and federal agencies for shelter belts, erosion control, strip mine reclamation, wildlife habitat, and was widely marketed as an ornamental. The shrub has now become naturalized in suitable habitats scattered throughout the eastern and Midwestern U.S.... Autumn olive grows well in disturbed areas, open fields, margins of forests, roadsides, and clearings. Because the fruits are eaten by a variety of wildlife, the seeds may be distributed into forest openings or open woodlands."

Yes, we planted this on purpose.

Because it makes lots of edible berries, birds are a huge distributor of the seeds. You will often see trees in an open field surrounded by these shrubs, seeds being dispersed by birds pooping them out as they sit on the branches of the tree. It seems to grow especially well around black cherry but I don't know why, and of course black cherry is the predominant tree on our property.

We began our autumn olive removal last fall and were thrilled with the difference it made. In some places native flowers have already started to make a comeback, in others we planted ground covers like wild strawberry to try to discourage other non-native plants from taking hold.

I have been eager to start removing more of this shrub (fall is the best time to do so) and the recent warm weather has provided me with the perfect opportunity to get started. My "target area" today was near and around a cherry, seen in the background in the photo below. As you can see, the tree is virtually hiden by the shrubs, even though there are no leaves on them!

Here are the tools of the trade. The control for this, as with many other invasive shrubs is simple: Cut the plant near the ground and treat the cut ends with Glyphosate, better known as Round-Up. However, Round-Up is only a 2% solution, and for this a 20% solution or stronger is recommended. Solutions of 40% can be purchased just about everywhere, and I do not dilute it--I don't want these little buggers growing back! I use the dish soap scrubber to apply the herbicide and keep it in this container so that I don't drip it all over the place. A sharp saw and a good pair of loppers are essential, as are good, thick gloves--autumn olive has sharp pokey bits!

After toiling away for the better part of the day, it went from this:

To this:

Now ain't that pretty! I hope to get this area reestablished with some native grasses, namely big bluestem, and some native flowers. Now I can't wait for spring! But in the meantime, there's more autumn olive to annihilate!

And what a beautiful shape this tree has, now that you can see it.


  1. Enjoyed looking thru your blog. Good hints on invasives and the tamarack pictures were fabulous! I'm in process of converting my lawns to native plants and the oak woods by adding native wildflowers. Great fun!

  2. much better! this was a great entry Marie, keep it up! ~Heidi

  3. There's a great book out, Invasive Plants of the Upper Midwest by Elizabeth Czarapata that is full of information about identification and control methods. It's the "bible" of habitat restoration.