Fresh red currants—with their juicy zing—have always been a favorite of mine. Delicious on plain yogurt or vanilla ice cream, they also shine in a meringue torte where their tartness nicely counters the sweet meringue. And, thanks to my prolific bushes, currant jelly and syrup are a mainstay at my home.
But black currants?
I loved them in Europe, which currently produces nearly all of the world's supply of black currants. I didn't realize they were rare in the U.S. until I read recently that most Americans have never had the fresh berries!
Sure, jams and jellies can be had—many of them produced in Europe—as well as cassis liqueur. However, I'm not going to find a quart of just-picked black currants in my local farmers' market any time soon because the plant continues to be banned in Michigan (and many other states)!
As far back as the 1600s, black currents were grown here in the States (red currant flowers and unripened berries shown above). The crop as a commercial endeavor, however, proved unreliable. According to R. Wellington et al. in a 1921 article, unripened fruit often dropped from the plant (called "running off") or the bushes developed nettlehead, a virus that causes the leaves to curl up.
The problem in the U.S., however, proved moot. Early in the 20th century, the U.S. banned commercial black current plants and ordered existing plants destroyed. It turns out that the plants can host an intermediate development step of blister rust—a parasitic fungus that kills white pines.
And, as outlined in a 1928 U.S. Department of Agriculture Farmers' Bulletin, the white (or five-needled) pine:
- was one of the country's "most valuable timber trees," worth over $500,000,000 ($8,865,491,329 in today's dollars)
- grew rapidly, over large regions of the country
- was a high-yield crop that produced high-quality lumber with many applications
- was prized as an ornamental tree
- was instrumental in developing U.S.industry and agriculture
Europe had the same blister rust problem but, unlike here, the berries were more important than the white pines. The fungus evidently came into this country via white pines imported from Europe in 1898–1910, a period when the U.S. logging industry was so active that it needed European stock to replenish supplies.
Interestingly, an infected tree cannot infect a healthy one. Rather, this fungus requires two different hosts. When blister rust is on a pine tree, it releases long-lived spores that can travel many miles to infect black currant and gooseberry plants (cultivated black currants are favored). Once infected, those plants readily infect their neighbors. The spores continue their development and, in turn, release spores that subsequently infect and kill white pines.
The Invasive Species Centre of Canada explains:
There are 2 main types of spores produced in the lifecycle of WPBR [white pine blister rust]: aecial spores produced on white pine hosts and basidiospores produced on Ribes (currant and gooseberry) hosts. By alternating hosts, the fungus can survive longer and continue the cycle of infecting new white pine trees.
Early recommendations were to destroy black currants near white pine stands, as shown in this illustration in a U.S. Department of Agriculture publication (Detwiler 1928). Unfortunately for the currants, they preferred the same environment as white pines and were often in close proximity.
Eventually all commercial operations—and even plants for home gardens—were eliminated and banned. Small harvests of berries were nothing against the highly lucrative logging industry.
Note that blister rust did not infect red currants (which were grown in greater quantities than black currants). Also, the Department of Agriculture (1928) was not without some empathy, stating that although the "cultivated black currant is of no great commercial value in this country . . . that it is prized in individual cases is, of course, fully understood."
Although fungus-resistant varieties were developed in the mid-1960s, only a few states allow the plant to-date, even though the white pine industry is far less vital to our economy than it was in the early 1900s. And even now, blister rust management focuses on protecting white pines from black currant plants by keeping them physically separated, which remains the most effective strategy.
As I mentioned earlier, black currant products are available in the U.S. (many imported from Europe). This black currant tea from TeaHaus, Ann Arbor, for example, boosts black tea leaves dotted with intact black currants.
This flavorful, robust tea is nicely tart when iced, and serves as a great entry point to black currants if you haven't had them before.
Black currants are slowly growing more popular as we learn (a) that they exist! and (b) that the berries are loaded with vitamin C, polyphenols, anthocyanins, and more. They've been promoted as a nutraceutical and a functional food product, mostly as a supplement, extract, concentrate, and so on. Studies have shown some promising results. However, the anthocyanins—which give the berries their color and which are often used as part of functional foods—have low bioavailability, meaning they aren't readily available for our body to use.
Yet, regardless whether they effectively prevent or alleviate any specific health condition, black currants are good for us in general, just like any other fruit. Enjoy them because you like them!
And the next time you pass a majestic white pine stand, think of the berries that were sacrificed for the trees. As the U.S. Department of Agriculture stated in 1928:
The blister rust makes it necessary to destroy currant and gooseberry plants already growing and to prevent new plantings wherever the white pine is an important forest tree and there is danger of that disease being spread to valuable forest areas.
Sources:
–Detwiler, S. B., Black Currant Spreads White-pine Blister Rust, United States Department of Agriculture. January 1928.
–Invasive Species Centre, "White pine blister rust," accessed 5/24/24.
–U.S. Department of Agriculture, Office of Information, Farmers' Bulletins Nos. 1376–1400, United States Government Printing Office, Washington. 1928.
–Wellington, R., et al., "The 'running off' of black currants," Journal of Pomology and Horticultural Science 2(3):137–159. 1921.
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