Magnolia soulangeana ‘Susan’ – Standards (Susan)

Magnolia x soulangeana ‘Susan’ is a hybrid raised at the U.S. National Arboretum in the 1950s. It is the progeny of M. liliiflora ‘Nigra’ and M. stellata ‘Rosea’, a pairing selected to push the flowering season back by two or three weeks compared with the old saucer Magnolia and thus reduce damage from late frosts. The result is a shrub or small tree with a neat, rounded habit that remains compact for years. It grows to an ultimate height and spread of about 3–4m, typically reached over ten to twenty years, and some references of note claim that well‑grown specimens can eventually stretch to around 5m where conditions suit.
Its stems naturally branch from low down, forming a broad ovoid crown, and we have found it equally comfortable trained as a multi‑stemmed shrub or lightly limbed up as a small ornamental tree. The floral display is what makes ‘Susan’ special. Deep reddish‑purple buds open from crescent‑shaped buds into goblet‑shaped blooms 10–15 cm across with six slightly twisted tepals. The tepals are rich purplish red on the outside and a softer pink within, and emit a light, sweet fragrance when the sun warms them.
Because the flower buds are produced on wood formed the previous summer and open from mid‑April into May, they usually avoid the early spring frosts that blacken so many Magnolias. Given a warm summer, ‘Susan’ may even throw a few additional flowers in July or August. After flowering, ovate mid‑green leaves up to 15 cm long unfurl, creating a lush canopy that turns yellow‑bronze in autumn.

‘Susan’, like most Magnolias is happy in most soils that retain moisture without becoming waterlogged. The best soils: neutral to slightly acidic loam, clay or sandy soils. Avoid chalky conditions. A sheltered position in sun to partial shade is ideal. Avoid exposed north winds and warm south‑facing walls that might encourage buds to open too early. Because Magnolias have fleshy, brittle roots, it is best to prepare the site thoroughly, plant while dormant and then leave the plant undisturbed. Mulching around the root zone helps keep soil cool and moist.

Once established, ‘Susan’ is hardy enough to withstand most British summers, though careful responsive watering is required in very dry spells. Pruning should be minimal: remove only dead or damaged wood after flowering, ideally between midsummer and early autumn. Heavy cuts spoil the natural form and can reduce flowering.

Hardy throughout most of the UK ‘Susan’ shrugs off winter temperatures and rarely suffers serious pest or disease problems. Nonetheless, it can be troubled by scale insects, thrips, snails or leaf spots; good hygiene and avoiding waterlogging will keep most of these at bay. For gardeners with limited space, the compact habit, restrained height and prolonged flowering period make Magnolia ‘Susan’ one of the most reliable and charming Magnolias.