Flowering Plum Prunus cerasifera Oakville Crimson Spire

Oakville Crimson Spire is an Australian bred flowering plum, selected at Oakville in New South Wales for one thing above all: it grows up rather than out. The crown is narrow and upright with the branches held tight to the leader, and the foliage is deep crimson purple through the warm months, darker than the older purple leaf plums and slower to fade in heat. Pale pink single blossom covers the bare stems ahead of the leaves. It is a tree for narrow verges, fence lines and repeated driveway plantings.

Sun for colour, and the graft to watch

Give it full sun. Foliage colour is a direct function of light, and the same tree that sits crimson in the open goes a muddy bronze green in half shade. It suits temperate and cool districts through Victoria, New South Wales, the Adelaide Hills and the south west of Western Australia, and it wants soil that drains, moderate water and a mulched root run kept clear of lawn. In a row along a boundary or a driveway, allow for the column to broaden gradually with age, because the young tree looks narrower than the tree you will have in fifteen years.

The one to watch is the graft. Like the flowering cherries, this is a named selection budded onto a rootstock, and any shoot that appears below the union or straight out of the ground is rootstock rather than Crimson Spire. Left alone, those green leaved suckers grow faster than the top and people end up with a scruffy green tree wondering where the purple went. Rub them off at the point of origin as soon as they show, and keep mulch and soil clear of the union.

Where it sits against the columnar pears

The closest match in this range for shape is Ornamental Pear Capital, which is also a tight column for a narrow space. The difference is what the tree does for the other eleven months. Capital carries glossy green summer foliage and turns red to purple only in late autumn, while Crimson Spire holds dark crimson purple foliage all season and reads as a permanent block of colour rather than a seasonal one. Take the pear if you want a green tree with a big spring and autumn moment on a slightly larger frame. Take this if you want dark foliage against a rendered wall or a light fence from spring through to leaf fall.

Pruning a young plum and keeping it clean

Prune ornamental plums in late summer or early autumn, in dry settled weather while the wood is still active, rather than in wet winter when silver leaf and bacterial canker get into fresh cuts. Keep it light: remove damaged or crossing wood, take out any shoot competing with the leader, and otherwise leave the natural column alone. Feed as the buds break with a balanced slow release fertiliser and water through the first couple of summers to establish. A light crop of small plums may set, and it is rarely heavy enough to be a problem over paving. More blossom trees sit under flowering cherry.

Choosing a size

This plant is available in 8 sizes, from 300mm up to 200L, priced from $149.00 to $1129.00 per plant. The size shown is the pot the plant arrives in, which is the rootball, not the height of the plant. Every size here is established stock rather than a starter plant, so this line is intended for immediate effect rather than for growing on. Not sure which to choose? Read our guide to choosing a tree for a small backyard.