'Ohio Everbearing' black raspberry

When I first heard about the 'Explorer' primocane-fruiting black raspberry, I was convinced it was the first such variety. As it turned out, I was wrong, as numerous such cultivars existed by the turn of the century, although very few ever achieved any importance.

An exception to this, however, is the very first primocane-fruiting black raspberry, 'Ohio Everbearing'. Although not a major commercial success, this variety remains significant as one of the very first cultivated American selections of Rubus, and probably the first named black cap (given the abundance of wild black raspberries, it probably took an unusual trait such as fall-fruiting to warrant a name and cultivation).

'Ohio Everbearing' was discovered in the wild by Nicholas Longworth. Longworth was a self-made millionaire banker from Cincinnati, which in 1804 when he moved there was almost the western frontier. Although his family remained important in local and U.S. politics, and he left an estate worth $10 million when he died in 1863, Longworth's most lasting legacy is as a horticulturist. Often called "The Father of American Viticulture" (a title sometimes applied to his correspondent, John Adlum), Longworth was an avid collector and disseminator of fruit varieties. He championed first the 'Alexander' and then the 'Catawba' grapes and introduced at least one strawberry of his own creation.

Everbearing Black Caps listed in Fred Card's Bush Fruits (1920) American Everbearing Cottier Everbearing [Grigg's] Daily Bearing Earhart Everlasting Every Day Fadely General Negley Hixon's Everbearer Kagy Everbearing King of Cliff's Lum's Autumn Black Raspberry Lum's Yellow Canada Miller's Daily Bearing Munson's Everbearing Mystery Ransom's Everbearing Sweet Home Wonder

Longworth found the original 'Ohio Everbearing' somewhere in central Ohio, where he had retreated in the fall of 1832 to escape cholera outbreaks in Cincinnati. Despite it being September or October, he "found a raspberry in full bearing, a native of our state, the only everbearing raspberry I have ever met with. I introduced it the same winter into my garden, and it is now cultivated by me in preference to all others, and my table is supplied from the beginning of June to frost." Although the variety struggled somewhat on the gravelly soils of his fields, it performed better on clay soils, and Longworth was convinced it might have a future, especially in England. He sent plants there, as did A.J. Downing, though it seems have had little impact there. The legendary Dr. Hogg did note its existence in England as late as 1884, when it was probably gone in the U.S. (Incidentally, in my hypothetical strawberry-themed band, my stage name was going to be "Dr. Hogg").

Longworth was among the foremost horticultural authorities of his day, and an everbearing variety of raspberry would seem to be a major development, so it seems like it should have caught on, but while he and a few others cultivated it commercially, it never seems to have. Black caps, in general, have never attained commercial prominence, perhaps because they were foreign to European tastes, and thus unable to compete with the more familiar red raspberries. Many other everbearers, such as 'Grigg's Daily Bearing', 'Miller's Daily Bearing', and 'Lum's Autumn Black' were selected from its seedlings. (Indeed, I rather suspect most, if not all, of those everbearing black raspberries that appeared in the second half of the nineteenth century may claim it as an ancestor. Most of these seem to originate in Ohio, Kentucky, Indiana, or Illinois, the areas nearest the discovery and commercialization of Longworth's variety).

Primocane-fruiting black raspberries, revisited

I was pleased to find a note in my e-mail this morning from Pete Tallman, developer of the 'Explorer' black raspberry. I mentioned 'Explorer' two years ago (have I really been at this that long?) as an exciting development in a crop in which very little breeding has been done (and, frankly, very little breed success obtained).

Unfortunately, 'Explorer' has not really been a success. I've seen it twice, both times under tunnels: once in Pennsylvania, where it had virtually no fruit and a powdery mildew problem, and another time in upstate New York, where the plants looked healthier but fruit set was still poor, though better. I was rather disappointed, as I'd been pretty excited about the thing.

Tallman's message today explains a big part of the problem: 'Explorer' is not self-fertile. Apparently his field featured things that flowered and provided adequate pollen at the right time, so the problem was never evident under his conditions. This fits with what I saw: the tunnel at Penn State where I saw it had, if I recall, only one other variety in it, while the one in NY, where it had at least some fruit, had several.

While unfortunate, this isn't entirely shocking, as self-incompatibility is fairly common among wild, diploid Rubus, and 'Explorer' is not far removed from the wild source of the primocane-fruiting trait that Tallman discovered. (Not surprisingly, the trait hasn't persisted very long in most commercial types).

Anyway, all is not lost. Tallman has selected another primocane-fruiting black raspberry, dubbed PT-2A4, which does pass the self-compatibility test, and has other desirable traits compared to 'Explorer'. As he describes it:

"Compared to Explorer, the PT-2A4 berries are larger, higher drupelet count, and smaller seeds. PT-2A4 holds my all-time record for a single primocane black raspberry at 3.82 grams. Admittedly, that's a max berry, not an average, but I gotta track something, and average isn't awfuly interesting. Maybe with a little fertilizer this year I could break 4 grams. Unfortuantely, PT-2A4 hasn't captured the reduced thorniness of Explorer, so there remains further breeding down the road to see if I can tie that trait back in again."

He also included a link to his website, which includes a page for PT-2A4.