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At this time of year attention starts to turn back to our tree collection and the promise of brilliant autumn colours to come.
Nyssa sylvatica – otherwise known as the sour or black gum – is up there with the best. One of the few deciduous trees to turn truly orange at points, as well as the more commonly encountered yellow and scarlet shades. The whole effect together, with parts of the tree burning orange, whilst others crackle red, gives the impression of a tree on fire.
Otherwise, they have glossy green, ovate, leaves throughout the summer, as well as small, greenish white flowers. Female trees also produce small, bluish, fruits loved by wildlife but that are very bitter or sour, hence the sour gum.
There are roughly 12 species of Nyssa in total, native to North America and Asia, but this species in particular – N. sylvatica – is usually found growing wild in the swampy regions of Eastern USA, where it can live to be over 600 years old.
The genus is named after Nysseides, the Greek water nymph of rivers, streams, lakes and marshes, but in cultivation, Nyssa will in fact grow in a variety of different conditions, including relatively dry soils, as long as they’re not planted in too much shade.
They do, however, make a very large mature tree, up to 15 metres tall and 10 metres across. Plus, they are best planted alone, as a single specimen with plenty of clear space around them, so as their autumn colour and general good rounded form can be best appreciated from some distance away. Factor the two things together and it’s clear that a very large garden indeed is needed for a prize Nyssa sylvatica.
Nevertheless, there are numerous smaller forms now available, which can give the same effect in a smaller space, like the mid-sized N. sylvatica ‘Miss Scarlet’, which grows to 10 metres tall, or the weeping N. sylvatica ‘Autumn Cascade’, which is smaller still with a maximum of 4 metres in height.
There are other alternatives of course; deciduous Euonymus – the spindle trees – and Japanese maples offer all sorts of fiery shades on plants better behaved in the smaller garden, but if it’s orange you want, I’ve never seen anything better than Nyssa sylvatica.