Magnolia: the Magnificent Heralder of Spring

Magnolia

Magnolia is a large, ancient genus with fossilised specimens dating back over 20 million years ago. The genus is named after Pierre Magnol, a 17th Century botanist. In our opinion nothing beats the sight of a Magnolia in full flower. Like sign posts to the beginning of the Spring season.

Site and conditions


For best growth and flowering, site magnolias in full sun in a fertile, moist garden soil.

On dry, alkaline soils consider Magnolia grandiflora and M. delavayi. On moist, alkaline soils try M. kobus, M. × loebneri, M. seiboldii, M. stellata and M. wilsonii. M. grandiflora and M. virginiana will tolerate wet soils

Some later-flowering deciduous species, such as M. wilsonii and M. sieboldii, will enjoy light dappled shade

A sheltered site is important. M. grandiflora and M. delavayi grow best on a warm wall and may not survive in regions where the temperature drops below -5°C (23°F). Frosts can damage flowers in spring and evergreen foliage in autumn

M. grandiflora is not especially 'windfirm' and may need staking when planted in the open, even when quite mature

Magnolias, especially evergreen ones, are commonly grown against walls. Despite this, reports of damage to buildings by magnolias are uncommon

Plant as for other trees

Magnolias can be grown in containers


Pruning and training


Deciduous magnolias:

Pruning is seldom required, with the following exceptions:

Shape trees at planting time by removing weak and badly placed growth and tipping back long shoots

Heavy pruning of mature magnolias can induce watershoots (long, vertical, vigorous shoots) and dieback. Routine pruning is therefore usually restricted to removing deadwood and watershoots

When pruning to limit size, aim to maintain an open, balanced crown by thinning out stems to the trunk or to a sideshoot. Stage the pruning over several years to avoid stressing the tree

Renovation should also be done over two or three years and trees can be slow to recover

Prune branches back to a natural fork to avoid leaving unsightly stubs

Cuts bleed if pruned in late winter or early spring so pruning should only be done between mid-summer and early autumn

Evergreen magnolias:

Young trees need no pruning other than shortening of lengthy, young branches and removal of lower boughs, where a bare stem is desired

Hard pruning is tolerated when renovation or repair of storm damage is required. Cut back to the main framework or even beyond. However, it is safest to spread this work over several years

Otherwise, prune free-standing trees in spring, as growth begins, and wall-trained specimens in summer


Wall-training:

The evergreen Magnolia grandiflora flowers and grows particularly well if trained against a sunny wall;

Wall-trained trees are trained by tying to wires or other supports, initially tying-in shoots at 45 degrees, then lowering them to the horizontal the following season

Regular pruning consists of removing shoots growing towards the wall, and shortening outward-growing ones to one or two leaves

If these outward-growing shoots bear flower buds, pruning can be delayed until immediately after flowering.


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