Prunus cerasifera and spinosa
February 27th 2011, in Trowbridge. Prunus cerasifera (Myrobalan Plum, Cherry Plum), a haze of thousands of green-creamy buds. (Click photo to see it better.) This is the earliest semi-wild Prunus to make a showing, and these trees are earlier than any of the others in my area, probably because they're growing in a sheltered spot over water (the River Biss).
Within the crown a few sheltered blossoms had already decided to go for it. Some of these early ones have six petals, like the one on the right (below).
Being particularly incurious I have never wondered before what "Myrobalan" actually meant. I just assumed there was probably some part of the world called Myrobal or Myrobalia where this plant originated. Not so. The tree is native to large areas of Europe and Asia (though not the UK), and the general etymology of "myrobalan", according to something I read on the web, is : "Obsolete French mirobolan, from Latin myrobalanum, fragrant oil from seeds of the horseradish tree (), from Greek murobalanos : muron, perfume + balanos, acorn." Eh? Well, as far as I can make out the name became attached to a number of small tree species (e.g. the tropical fruit tree Phyllanthus emblica, commonly known as Myrobalan) and then ended up becoming applied to the cherry plum, referring to the smallish globular fruits. Or did the transfer go in the other direction? To add to the confusion, the word was inevitably conflated, in many people's minds, with "mirabelle". This history of promiscuous re-attachment is fairly standard for non-scientific plant names (and scientific ones too, if they're given half a chance).
(A few weeks later, in West Swindon)
Mid-March 2011, now smothered in blossom. A very common tree along the busy roads here.
By this time, in any normal year*, P. cerasifera is starting to overlap with early-flowering blackthorn (P. spinosa). It's quite common to find the two species entangled, as below (blackthorn at the front, cherry plum further back - note the emerging leaves).
[*In 2013 it was different. P. cerasifera was off and running by the end of February, as usual, but then it ran straight into the coldest March in half a century; a sustained spell of arctic high pressure with day after day of freezing temperatures. All the other shrubs slammed on the brakes, but P. cerasifera was already committed. So it had March all to itself, standing there miserable and cold, crying out to non-existent insects, at last reluctantly fading. The weather finally broke around 6th April - I saw blackthorn coming into flower on the 9th. By then, some of the cherry-plums (including the earliest flowerers) had long since shot their bolt. The rest, however, made remarkable efforts to elongate their flowering season and thus salvage something from the year. They looked strangely impressive in a battle-scarred way; most of the crown was a mass of brown withered blossoms but lines of new blossom crept over the surface, mostly low down and near the tips of the shoots.
I also saw P. cerasifera in flower on 3rd January 2016, following the mildest December on record.]
Cherry plum sometimes has an occasional thorn, but anything that looks like the above is definitely blackthorn.
(Above). Blackthorn buds, snapped in mid-March 2011. (Below) Blackthorn in flower a week later.
The flowers are the most similar things about the two plants.
Here are some tips I picked up from the Facebook Wild Flower group:
If last year's stems are green, it's P. cerasifera. If they are brown it's probably P. spinosa but that's not 100% reliable in my experience. P. cerasifera blossom is accompanied by opening leaves; P. spinosa appear before the leaves. P. cerasifera twigs arise at a more acute angle from the parent stem (P. spinosa twigs are almost at right-angles). P. cerasifera flower-stalk is as long as petals, P. spinosa flower-stalk is shorter than petals. P. spinosa petals tend to be narrower. P. cerasifera sepals are more likely to reflex.
The photo above is P. spinosa, the photo below is P. cerasifera. You'll just have to take my word for it. The cherry plum flowers are a little larger, on average. (OK, so this blackthorn flower happens to be a six-petaller, but those are equally frequent on both plants.)
(Below.) Photo - it's P. cerasifera this time - to show that when the corolla is six-part, then so is the calyx.
Above, young fruits developing (April 20, 2014).
The blossoms of P. cerasifera may be very uniform, but the fruit are surprisingly varied in size, shape, colour and flavour - and they're usually delicious. This is an abundant wild food around towns, for those who care about it. The pictures below were taken in August.