Saturday, August 29, 2015

Blackberries and Summer

Note: This program first aired August 29, 2015.

Late summer is one of my favorite times of year. The expansive energy of summer starts to wane as plants start their journey to winter dormancy. Birds cram in the as many fat and juicy insects as they can, and start making their way to warmer climes. For many of us humans the school year is starting back up and though we mourn the end of summer the structure of fall is just what we need. And most importantly, late summer is when my favorite wild fruit ripens and is there for the taking, road side and trailside.

Blackberries are a common late summer fruit here in Maine, coming after the strawberries of early summer, the blue berries and raspberries of mid to late-ish summer. Blackberries mean the end really is nigh. Some summers in recent memory, the chill of fall started before the blackberries were able to fully ripen, and we never got our end of summer treat.

When we say “blackberries” we are really talking about several species of plants in the genus Rubus. Rubus is a real head ache for botanists, as the species are difficult to tell apart and hybridize (or cross breed) in the wild readily. This cross breeding ability has made it easy to develop all kinds of interesting agricultural cultivars, but it makes sorting out the taxonomy of wild plants very difficult. Estimates for the number of Rubus species world wide range from 250 to 700 because different botanists treat the genus with differing degrees of discernment. On the one hand we have the “megaspecies” approach, lumping many disparate species together based on one common characteristic. On the other hand, similar plants can be separated into different species based on minute or inconsistent characteristics. Hence the range, the taxonomy of Rubus is still an open debate.

Regardless of exactly how many species are in the genus, Rubus includes along with blackberries and raspberries, plants with dreamy sounding names like dew berry, cloud berry and baked apple berry. All of these berries are technically aggregates of a type of fruit called a drupe. Drupes are stone fruits, consisting of a fleshy pulpy layer surrounding an inner hard seed, think a peach, plum or avacado. Blackberries and their kin are made up of lots of little drupes, called drupelets, clustered together in one delicious berry. These berries mostly share another characteristic in their growth form. They are perennial, growing from multiyear root system, but the above ground portion of the plant is a woody cane that lives as a biennial, or for two years. The first year the cane grows it is called the primocane. It has lots of leaves but no flowers or fruit. Think about all the lush green leafy blackberry brambles you have seen and wondered why there were no berries. They were primocanes, that’s why. The primocanes overwinter and produce lateral branches that flower and fruit the second year. These flowering canes are referred to as floricanes. And if you want to take on the challenge of identifying Rubus to species, knowing the difference between floricanes and primocanes is essential. In any given patch of blackberries, there should be both primocanes and floricanes, so this year’s lush fruitless bramble of primocanes should yield some fruit next year, but its root stock will also put up more primocanes next year, which may explain why some blackberry brambles I watch never seem to produce fruit. It also may be that black berry floricanes especially sensitive to cold, much more so that red raspberries for example. And after last year’s cold winter, I notice that the wild raspberry crop this summer has far surpassed what it usually is, and blackberries, sadly are harder to come by in my yard.

I grow cultivated raspberries, enjoying them from the freezer all winter long. The blackberries though, have defied my attempts at domestication. And once in a bumper crop year I froze some, only to find them disappointingly tasteless when thawed in December. For me blackberries are a fruit that demand to be appreciated on their own fleeting terms—on the side of a dirt road, ideally warmed by the sun, going directly from cane to mouth, staining fingers inky purple. Enjoy them in the present as a foraging wild animal, it’s a marvelous way to spend the last few days of summer.


GoBotany is a great place to start learning about the different Rubus species in New England