It always surprises me how many people don’t notice the plants along our highways. I can’t be the only one driving down the road remarking the excellent pairing of plants nature makes in the median strips. Of course a lot of people bemoan that we have a poor range of woody nitrogen fixers so perhaps they don’t realize our median strips are clogged with one of the best woody nitrogen fixers known. Please say you recognize the common name: autumn olive?
It’s as though this plant were invisible to the general public. It is in fact one of the few elite plants to hit high nitrogen fixer status. This category starts at 160 lbs N fixation per acre, and doesn’t even have an upper limit.
This is the first N-fixer in the series that is not a legume. It is actinorhizal. The reason being it doesn’t use Rhizobium bacteria to fix N; the whole group, made up almost entirely of woody trees, use a filamentous bacteria called Frankia, which has quite a high salt, water, and drought tolerance.
Combine this with an early leafing, and in general shade tolerant disposition of Eleagnus, and you have a specimen rugged and ready for any terrain.
In fact its ruggedness is what gave it the green card to emigrate from East Asia to Northern Europe and the US. We needed something that could rehabilitate strip mines -places where land is stripped of its soil hunk by hunk to get coal under it rather than building an underground mine.
I’m not sure how widespread the practice is, but I have a lot of it around me -mostly done 50 years ago. Even today after rehabilitation, many of these sites look like a scene of Mordor (in fact many movies are made in strip mines for that affect) with grey and black rock and coal, and orange clay. Often there are huge ravines left that were used as personal dumps. Then most springs in them are some variety of toxic –either gray or orange red water.
So if this gives you a picture of what Eleagnus was brought to America to live in, and that it thrived in, you get my meaning for rugged.
Obviously any food forest where fruit trees are expected to grow will be a walk in the park for Eleagnus. All the better because it is a fruiting shrub.
I remember the expression on my friend’s face when I first introduced him to the shrub. He was at first wary of eating off a random bush in the middle of a half wild field, but once he tasted the berries his face lit up with surprise and copiously praised them saying they would be amazing in a salad.
I completely agree. The flavor to me is like a tart apple, although it has a more intense sweetness than any apple I’ve tasted. Some species like E. multiflora, commonly known as Goumi in Japan, naturally has much larger fruit, and about the same flavor I’m told. There are several varieties of E. umbellata bred-up for size and flavor, such as ‘Ruby, and ‘Amber,’ which I have; although I haven’t been able to taste any yet to say how much better they are.
A more sensuous experience Eleagnus has to offer are its flowers. I love their scent-and others do too; one woman said she’d pay me if I could dig her a wild bush to smell in her yard. It lands somewhere between a floral and a gourmand in terms of perfume, being a vanilla spice scent. Thick as it is, I’ve caught the scent wafting down wind a whole fifty feet from the plant.
As for its form, it’s highly variable. In wandering strip mines I’ve seen some with six inch single trunks that are more fitting as trees stretching for the upper story, and shrubs with dense canes coming up from the base as a thick bush. Coppicing in the sun will produce the latter effect, limbing up in shade the former.
Limbing up in shade is one place Eleagnus does very well because it can take shade and still produce a decent amount of N for the space it takes. For the most nitrogen and fruit though, it’s better to let them get sun in the overstory, or have some sun in the understory where you can pick them.
So after all that, I just hope you don’t get into any wrecks studying your new found highway inhabitant. Perhaps it’s better to study them in your food forest. They’re far more productive that way.