Most magnolias are trees, but Magnolia stellata is a shrub growing slowly to about 9 ft. It is an exceptionally beautiful plant, with rather narrow-petalled white flowers, very freely produced in March and April. There are also pink varieties, one very pale in colour named rosea, another, a little deeper, named rubra. All succeed best in neutral or moderately acid soil and a rather sheltered position as the flowers are apt to be spoiled by frost or cold winds. Pruning is undesirable. It is advisable to purchase young plants in containers as, like most magnolias, this species resents root injury.
If you have a south-facing house wall, there is no finer thing you can plant against it than a Magnolia grandiflora. Introduced from the southern United States in the eighteenth century, this magnificent wall shrub can be seen setting off the brick or stone of English country houses. Given time, it will grow to 7.6m (25 ft) or more. An evergreen, it flowers from July to September, with— as its name suggests – the biggest blooms of any magnolia, creamy white, heavily fragrant, and up to 22.5 cm (9 inches) across the bowl.
Unlike some magnolias, it is not a lime-hater. Among the cultivars available are two which get over one of the disadvantages of magnolias by producing flowers on young plants. They are ‘Exmouth’ and ‘Goliath’, which, as its name suggests, has bigger flowers than those of the species.
General care: This magnolia is worth going to some trouble over. Prepare the site by digging it out deeply and working in plenty of well-rotted compost. Plant in April, and provide shelter from cold winds, especially when the plant is young. Put in stakes for its support until it is established on the wall, and give a spring mulch of compost or leaf mould. Only its main shoots need to be tied to the wall. In spring cut out any basal shoots which are facing away from the wall.
Propagation: The magnolia is not easy to propagate. Seeds take more than a year to germinate, and cuttings and layers take a long time to root. Layering is the most successful method. Peg the shoots down in the spring, but allow at least two years before separating from the parent.
Pests and diseases: Generally trouble-free, but frost-damaged shoots may become diseased. Guard against this by cutting back the damaged shoots in the spring.
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M. x soulangeana, common magnolia, a cross of M. denuclata and M. liliflora, is 3-6 m tall and 3 m broad. There are many varieties differing in the size and shape of the flowers, from white to a deep purplish-pink, flowering at different times; ‘Alexandrina’ is an early flowerer with dark purplish-pink flowers, white inside; ‘Lennei Alba’ has strong, pure white flowers; ‘Norberti’ is an upright tree with whitish-pink flowers; ‘Rustica Rubra’ has large, spherical, deep pink flowers; the shoots are suitable for cut flowers; requires rich, moist, acid or neutral soil, rich in humus, and sun or semi-shade.
M. stellata, star magnolia, is a slow-growing shrub up to 2 m tall and broad, which flowers in March-April. It has silky, hairy shoots, leaves 4-10 cm long, and numerous white flowers, 7-8 cm across, with 12-20 narrow petals; ‘Royal Star’ grows more vigorously and has white flowers. These shrubs or trees are grown on their own or in groups in a sunny spot, sheltered from the frost and strong wind. It has a well-developed clump of roots and requires rich, moist, preferably loamy soil rich in humus; remove dead wood and trapped branches, prune back if necessary immediately after flowering. Propagate from cuttings, by grafting (under glass), layering (August/September) and from seed, (this takes a long time, the seeds usually soon lose the strength to germinate).