Flowering Dogwood ‘Rainbow’ · Cornus florida ‘Rainbow’

Cornus florida 'Rainbow' is a slow-growing, deciduous small tree reaching 4 to 6 m in height and 3 to 5 m in spread at maturity, with a rounded, well-structured crown. The cultivar is distinguished by variegated foliage: oval leaves carry a green centre with cream to yellow margins through the whole growing season, then shift to red and purple tones in autumn. As a specifier's piece, it functions as a small ornamental focal point rather than a structural tree.

Climate fit inside Spain is narrow. The species belongs to the humid temperate deciduous forests of eastern North America and performs most reliably in the cornisa cantábrica, where cool summers, mild winters and acidic soils mirror its native range. It can be specified in shaded, well-watered northern meseta sites with the caveat that late spring frosts damage emerging bracts and hot dry summers compromise foliage quality. It is not a Mediterranean coastal or semi-arid southeast species; in the Levante, inland Andalucía or Almería its low drought tolerance and heat load on the leaves exceed its working envelope.

Water demand is the controlling specification variable. The first two to three summers require consistent irrigation, and mature trees continue to need reliable moisture on free-draining soils; behaviour under irrigation cut-off is poor and quickly visible in scorched leaf margins. Mulched root zones and afternoon shade reduce the demand, but the tree is not suited to a proyecto de ajardinamiento with severe water restrictions.

Soils should be moist, organically rich, slightly acidic and well-drained, excluding the alkaline calcareous substrates of much of central and southern Spain. The species is vulnerable to dogwood anthracnose and powdery mildew when stressed by heat or drought, so site selection is also a phytosanitary decision; the genus sits outside the current Xylella fastidiosa host range. Hardiness extends to roughly minus 15 °C, well beyond any Spanish project requirement.

Maintenance is otherwise low, limited to light formative pruning and occasional sanitary cuts. Use as an isolated specimen near patios, in courtyards or in jardín andaluz enclosures where the foliage and bract display sit close to the eye.