There are several myths about magnolias. One is that they grow very large, and you would certainly need a big garden to grow M. campbellii at 50’/15m, but there are many, many, smaller cultivars or species ideal for smaller gardens, like M. stellata with starry white flowers, or the ‘Little Girl’ series, perhaps the best of which is ‘Susan’, with narrow, tulip-shaped crimson petals, paler within. And there are magnolias, like Fairy Blush and Fairy White, which are small enough to be grown in large containers, as can M. stellata.
Another is that they must have a slightly acid soil, but there are cultivars that can be grown on a moist, slightly alkaline soil, like M. stellata, M. x loebneri ‘Leonard Messel’ or M. seiboldii (it is true that magnolias don’t thrive on thin, dry, chalky soils). Try a small cultivar, in soil-based, ericaceous compost in a large container if your soil is very alkaline, dry or chalky, and keep it well watered.
Another is that they take forever to flower, but this is not the case with modern cultivars, especially grafted ones.
Some magnolias are taller and narrower, others rounded bushes, and others yet are trees. Not all are pink, white or purple, there are soft yellow ones too, like M. Elizabeth. In fact, there’s one for every garden.
How to grow magnolias
The ideal soil for magnolias is fertile, moisture-retentive, and slightly acidic to neutral. If your soil is not that good, excavate a wide hole and dig in plenty of organic matter before planting, then mulch well to improve moisture-retentiveness and fertility, keeping the mulch clear of the stem(s). If the soil is very heavy, add some grit. Be sure to water in dry spells.
Choose your site carefully. Magnolias are slow-growing, but check the eventual size of your magnolia, as they don’t like to be cramped, and resent hard pruning. The site should be sheltered, and in full sun. Magnolias are very hardy, but early-flowering cultivars can lose their flowers to frosts, so don't plant in a frost-pocket, and choose later-flowering magnolias if your garden is a cold one – the lovely M. soulangeana hybrids often flower as late as May.
Choose a lively specimen showing signs of growth, and is not pot-bound. Be sure to plant grafted specimens to the exact level it was in the pot – the graft must be clear of the soil or it will rot. And be careful not to mulch too thickly near the stem, so you don’t bury the graft.
Magnolias are relatively pest- and disease-free, but if your garden is raided by rabbits, protect the trunk with wire-netting or a tree-guard (surround shrubby magnolias with wire netting attached to posts). Young trees can lose leaves to slug attack, so check the soil regularly and remove the little blighters; older trees can usually withstand attack.
Magnolias are generally shapely plants, and they dislike pruning as they can bleed sap, but if you need to remove a badly placed branch, prune deciduous cultivars in midsummer, after flowering is over.
Good species and cultivars:
Small shrubby magnoliasM. stellata: deciduous, rounded bushy habit, strappy white petals 5-8’/1.5-2.5m x 8-13’/2.5-4m
M. x soulangeana lilliflora Genie: deciduous, very deep burgundy goblet-shaped flowers, 10’/3m x 5’/1.5m
M. Fairy White: semi-evergreen, strappy white petals, 8’5”/2.6m x 8’/2.5m, tolerates clipping so can be used for hedging.
M. Fairy Blush: semi-evergreen, strappy shell-pink petals, 8’6”/2.6m x 8’/2.5m
Medium-sized magnoliasM. Susan AGM: deciduous, crimson-purple tulip-shaped flowers, 13’/4m x 10’/3m
M. George Henry Kern AGM: deciduous, pyramidal habit, scented soft pink goblet-shaped flowers, 13’/4m x 8’/2.5m
M. stellata Royal Star AGM: deciduous, strap-shaped petals white flushed pink, 10-13’/3-4m x 10-13’/3-4m
Larger magnoliasM. x loebneri Leonard Messel AGM: deciduous, lilac-pink goblet-shaped flowers, 26’/8m x 20’/6m – a wonderful cultivar
M. x soulangeana: the classic – deciduous, tulip-shaped, white to rose-pink flowers, paler inside, 20’/6m x 20’/6m
M. Black Tulip: small deciduous tree, red-purple tulip-shaped flowers on bare branches, 20’/6m x 10’/3m.
M. Elizabeth AGM: deciduous, goblet-shaped soft yellow flowers, 33’/10m x 20’/6m
M. campbellii: large deciduous, tree, to 50’/15m; rose-pink and white goblet-shaped, later spreading, flowers up to 1’/30cm across in the bare branches; not for the coldest areas.
- Alan Taylor IT Consulting