"Marionberries Are Here!" shout the signs. Offerings of marionberry shakes, pies, tarts, ice creams, sorbets, salads, and more litter menus across the state of Oregon come July and August. Tables at farmers markets get covered with baskets of the shiny blue-black berries. Smart shoppers order flats of these juicy berries to freeze and otherwise keep past the all-too-brief season. Marionberry season is serious business in the Pacific Northwest.
The marionberry is the queen of blackberries with a complex and rich earthy flavor that skirts that edge of bitterness found in many blackberries. Many tasters find a similarity between marionberries and the rich earthy juiciness of Cabernet grapes. It is sweeter and juicier than the Evergreen blackberries found in wild brambles up and down the West Coast. It is a medium-sized blackberry that ranges in color from very dark red to true black. It is grown exclusively in Oregon, where it is prized above other blackberries. In Oregon, marionberries are always labelled as marionberries or their more formal name, marion blackberries.
The marionberry was developed at Oregon State University in 1945 by crossing a Chehalem blackberry (a berry with native blackberry, Loganberry, and raspberry in its background) with a Olallieberry (itself a blackberry cross) and named after Marion county in Oregon. They were first brought to market in 1956. Marionberries are still held up as the blackberry to beat by berry breeders.
Marionberries, especially the darker colored ones, are beautifully glossy. Look for bright, plump berries without blemishes, mold, or sogginess if you're lucky enough to find fresh marionberries for sale.
Fresh marionberries are in season from mid-July to mid-August. Frozen marionberries are available year-round and work beautifully in baked goods like this Blackberry Cobbler or a Hazelnut Blackberry Crisp. Freezing your own marionberries is easy: simply rinse and pat berries dry, spread them on a baking sheet and pop them in the freezer, after about an hour they should be frozen through and ready to transfer to a sealable plastic bag or other sealed container and kept in the freezer for months (find stand-alone directions for freezing berries.
Like all blackberries, marionberries are high in antioxidants (vitamin C, gallic acid, and rutin in partiuclar), as well as containing phytochemicals like ellagic acid and anthocyanins. Berries are also an excellent source of fiber (1/2 cup berries has as much fiber as 3/4 cup of brown rice – go figure!).