- Mature height
- 10m to 15m (approx.)
- Mature width
- 8m to 10m
Magnolia grandiflora 'Greenback' is an evergreen cultivar of the Southern Magnolia with thick, glossy leaves that stay green on the underside rather than the rusty brown of most cultivars, which is where the name comes from. Growth is dense and upright. Large, fragrant, creamy white flowers open through late spring and summer.
Grow it in full sun to partial shade in most reasonable soils, ideally slightly acidic and well drained. It suits temperate, warm temperate and subtropical gardens, tolerates urban conditions and is moderately drought hardy once established. Growth is moderate at 20 to 40 centimetres a year. Water regularly through the first two summers and in long dry spells.
The dense habit makes it a strong privacy screen or windbreak, planted 2.5 to 3 metres apart for an informal screen or 1.5 to 2 metres apart for a tighter clipped hedge. It also stands alone as a formal upright specimen. Evergreen cover at 10 to 15 metres is hard to beat on a boundary.
Frequently Asked Questions
About Greenback Magnolia
What is Magnolia grandiflora 'Greenback'?
It is an evergreen selection of the Southern Magnolia with thick, glossy leaves that stay green on the underside instead of the rusty brown found on most cultivars, which is where the name comes from. It has a dense, upright habit and produces large, fragrant, creamy white flowers through the warmer months.
How big does Greenback Magnolia grow?
It reaches 10 to 15 metres tall and 8 to 10 metres wide in most gardens, and can push to 18 or 20 metres in deep soil with good moisture. That is a broad crown at maturity, so give it clear room away from buildings and boundaries. Trimming will hold it at any height above about 2 metres.
Is it evergreen?
Yes, it holds foliage all year and does not go bare in winter. Older leaves are shed gradually through the year rather than all at once, so there is a light ongoing leaf drop rather than a seasonal one. The leaves are thick and slow to break down, which is worth knowing near pools.
How far apart should I plant it for a screen?
Space plants 2.5 to 3 metres apart for a dense informal screen, or 1.5 to 2 metres apart for a tighter formal hedge that you keep clipped. For a row of individual trees rather than a solid screen, 6 metres apart lets each crown show its shape. Closer planting fills faster but the plants compete for water.
Does it need sun or shade?
Full sun to partial shade both work. Full sun gives the densest growth and the heaviest flowering, which matters if you are relying on it as a screen. In partial shade it grows a little more openly. It will take half a day of shade from a building or neighbouring trees without thinning badly.
Is it drought tolerant?
Once established it is moderately drought tolerant and copes with normal dry summers in temperate and subtropical gardens. The thick waxy leaves reduce water loss. It is not a plant for unirrigated arid sites, and a young plant needs regular water through its first two summers before you can leave it to fend for itself.
How do I prune and care for it?
Trim in late summer or early autumn after flowering, taking the tips back to shape rather than cutting into bare wood. Feed in early spring with a fertiliser suited to acid loving plants, and mulch the root zone. Water regularly through the establishment period and during long dry spells. Little else is required.