Prunus - early
(Above) Myrobalan Plum or Cherry Plum (Prunus cerasifera). Much confused - e.g. by me - with Blackthorn (P. spinosa) (below) but its flowers appear three weeks earlier, typically with (not before) the leaves, and it doesn't usually have thorns. For much more about this wonderful plant, click here.
(Above) Prunus cerasifera, variety 'Atropurpurea', usually known as Pissard's Plum. I first wrote that this early moment of beauty must be why its admirers are prepared to put up with the next six months of shabby brown leaves, but the truth is no doubt otherwise: they probably think brown leaves are cool.
Plums generally flower earlier than cherries - at this time of year you can tell the difference because plum-blossom stalks are in ones or twos, whereas the cherry blossoms are usually in larger bunches.
(Above) Almond (Prunus dulcis) - easily identified by the large flowers.
Almond is a short-lived tree so usually found in newer gardens. Some of the showier Almonds are actually a cross with Peach (Prunus persica), according to Alan Mitchell's Trees of Britain.
The bark is cherry-like on young saplings, with horizontal bands of lenticels; then it develops spiral cracks and soon turns almost black.
(Above) I photographed this (growing beneath an overhead walkway) on March 19th. Thank you to Nadia Talent for identifying it as an Apricot (Prunus armeniaca), which I never even knew could be grown as a street tree in the UK - the free-standing trees don't ripen fruit, though. This ignorance of mine was due to excessive reverence for the great Alan Mitchell, prone to arbitrary silence about certain tree species. But I can now say, with the Danish poet Inger Christensen:
abrikostræerne findes, abrikos-træerne findes
(apricottrees exist, apricot-trees exist)
[The translation by Susanna Nied inevitably and sensibly fails to register some of Christensen's minutiae, like the comma in this first poem. The Danish is more committed to the alphabet than you might guess from the English, e.g. in the B poem "hydrogen exists" where the original word for hydrogen is presumably "brint". Likewise in the "D" poem, words like "killers" and "poems" do begin with D originally, something like "dræber" and "digter" respectively (excuse lack of correct Danish grammar). And that's also why the K poem appears (in English) not to begin with K.]
(Above) Prunus 'Accolade'. One parent, at any rate, was Prunus sargentii, the other possibly Prunus subhirtella.