After the publication of the December column on cranberries, I received a letter from Lonnie Murray, appearing below. Since it includes a great deal of information on cranberries, both in the wild as well as in the garden, with Mr. Murray’s permission we are reprinting it here in lieu of my regular column. Except for some minor editing, it appears as he wrote it.
You’d asked if anyone locally grew cranberries… I have grown both Vaccinium macrocarpon and V. oxycoccus successfully for some time. I grow them in a bog garden alongside Venus flytraps, pitcher plants, sundews and native orchids. It has a soil mix that is a mix of 50/50 peat and sand. Most years I’ve not had to go to the store to buy the berries because the bog produces enough on it’s own.
Bogs, and bog gardens, are frequently misunderstood. People often assume they need to be flooded, shady, and mucky (i.e. high nutrient). In reality, bogs are acidic, low-nutrient sunny places that are often deceptively well drained. It is the drainage that keeps them low nutrient. So, to grow cranberries successfully, fertilizer is not necessary; indeed, it would kill most of the plants in the bog.
It’s worth noting that cranberries grow natively just over the mountain in the Shenandoah Valley, although they’ve now become quite rare. Indeed, the resort Shenandoah Acres was once a wild cranberry bog that contained so many native orchids that it was described by a botanist as a sea of pink when they were all in bloom. Sadly, long ago that cranberry bog was dredged, all the plants removed and then covered in sand to make the resort that exists today. I’m confounded why someone didn’t just start a “pick your own cranberry” farm instead. The irony of a site like this destroyed so that people can go there to experience “nature” is overwhelmingly tragic to say the least. Indeed, given that cranberries grow naturally in sandy moist soils in the valley near the mountains, I’ve wondered why no one is growing them commercially? Seems like a lost opportunity.
Anyway, our mountain bogs where cranberries live are quite magical places and deserve our respect and appreciation. These ecosystems also function to help filter contaminants and keep our waterways clean. Indeed, since rain gardens are often composed of a sandy media, with some modifications cranberries can be successfully included in them to treat storm water and help keep reduce the pollution of our rivers.
Perhaps some explanation is in order regarding bogs being “deceptively well drained,” as Murray notes. To the average person, the term “bog” connotes a very soggy place. Bogs typically occur in areas of high precipitation and low evaporation, so there is indeed abundant water. But since they often sit atop sandy soils, water flows through relatively easily, even if a layer of clay may sit beneath.
Over time, bogs can colonize shallow ponds by creeping in from the edges. Sphagnum, also known as peat moss, takes hold and acts as a sponge, absorbing a great deal of the water. As the lower layers of sphagnum die, they can accumulate to thicknesses of several feet. When harvested, this can be sold as peat moss, burned to provide heat, or used as a filter to provide the distinctive flavor of Scotch whiskies. Harvesting peat from bogs is only sustainable on a very small scale, however, and ultimately increases greenhouse gases in the atmosphere. But that would be a topic for a different time and another author.
Thanks again to Lonnie Murray for his input. He is the former Chair of the Albemarle County Natural Heritage Committee and is currently an elected director for Albemarle County on the Thomas Jefferson Soil and Water Conservation District. And I always appreciate hearing from anyone who may have more experience with a particular plant than I have had.
Raise a glass of your favorite cranberry concoction and toast the New Year, even if it is now a few days old!