Cercis canadensis Merlot

Position and soil. Full sun to part shade by both American references, with part shade best where summers are hot, by the Missouri Plant Finder; the North Carolina toolbox says it will grow in any well-drained soil, clay to sand, acid to alkaline. A Victorian wholesale grower's sheet says it does best in a deep, well-drained, fertile soil and should be kept off hot, windy sites.

Water and heat. The North Carolina toolbox says it tolerates heat and drought, unlike other cultivars of the genus, and puts that down to its leaves, glossy, rounded and smaller, which help it hold water and transpire less. The Victorian grower gives it good tolerance of drought and heat once established, but adds that redbuds in general do not like long droughts or wet spells, and the Missouri Plant Finder still advises regular, consistent moisture.

Frost. No Australian reference read gives Merlot a frost rating.

Pruning. Left alone it makes a multi-trunked plant with a low canopy; selective pruning while it is young gives a more tree-like form and a strong branch structure, the North Carolina toolbox says.

Problems. The North Carolina toolbox finds it mostly free of pests but names verticillium wilt, blights, mildew, dieback and canker as possible; the Missouri Plant Finder says canker can be a significant problem. Mowers and trimmers can damage the thin bark, the toolbox adds.

Status. Exotic: the Australian Plant Census holds only Cercis siliquastrum in the genus.

A Victorian wholesale grower gives Merlot as a feature tree for a small garden, and tags it for avenues, group planting and informal screening. The American references add small groups, patios, pollinator gardens, woodland understorey and street or lawn use. Against Forest Pansy, the same grower describes it as tighter and denser, with thicker, glossier and smaller leaves, and lists it at a smaller mature size, though the North Carolina toolbox's leaf figures for the two do not bear out the smaller leaf.

Merlot is sold under its cultivar name: growers list it as Cercis canadensis 'Merlot', while the Missouri Plant Finder files it as Cercis 'Merlot'; it is the same plant. A cultivar is not a substitute for its species, as the HortOS guide to reading an availability list puts it, so a line for plain Cercis canadensis is a different order. Its summer colour is uncertain on the references read: the Missouri Plant Finder has the leaves dark olive green by midsummer, and the North Carolina toolbox says in one place that they turn green in summer and in another that they do not fade. The Missouri Plant Finder says it does not transplant well and should be planted young and left undisturbed. Stock that crosses a state border moves under the state and territory biosecurity rules on moving plants and soil.