Alta Southern Magnolia

Alta Southern Magnolia (Magnolia grandiflora 'Alta') is the answer when you need height along a boundary and have almost no width to give it. It reaches about 8m tall and only 3m across in a home garden, holding a naturally upright, columnar form without any training. Large creamy white flowers open through the warmer months with a lemon and vanilla scent.

Why you'll love it

• Tall and narrow by nature. Roughly 8m by 3m, so it screens a two storey outlook from a bed barely wider than a garden path.
• The screen never takes a season off. Dark evergreen foliage holds through winter, when deciduous screens leave you exposed.
• Fragrance that carries. Large creamy white blooms through the warmer months, scented enough to notice across a courtyard.
• Roots that behave. Fibrous and non-invasive, so it can sit near driveways, paths and services where most trees of this height cannot.
• Low maintenance and hardy. Frost hardy, wind tolerant, salt tolerant enough for a coastal block, and drought tolerant once established.

Where it works best

Tall narrow screening. Plant 2m apart for a continuous screen. The columnar habit means the canopies close at that spacing without the trees shading out their own lower branches.

Driveways and feature planting. For a formal avenue, space at 3m to 4m so each crown reads as a distinct tree. The upright shape also suits a matched pair flanking an entry.

Growing Alta Southern Magnolia in Australia

Position and climate. Full sun gives the heaviest flowering and tightest form; part shade is tolerated with a more open habit. It suits subtropical, warm temperate, cool temperate and Mediterranean gardens, and frost hardiness means cold southern districts are no obstacle. Avoid the wet tropics.

Soil. Well drained and slightly acidic, with compost worked through the backfill. Waterlogging is the fastest way to lose one, so plant on a raised mound in heavy clay. Mulch 75mm deep, clear of the trunk.

Water and feed. Deep soak twice a week through the first two summers, then taper off as the roots go down. Feed a complete slow release fertiliser in early spring and mid summer.

Pruning. Very little is needed, and heavy pruning works against the shape you bought it for. Tip prune after flowering to thicken a screen, and lift the lowest branches only if you want a clear trunk.

What to expect when it arrives

This one is sold in a single size, a 400mm pot. That is an advanced plant, well branched and already showing the upright habit, which is the right starting point for a tree chosen for its shape.

Some leaf bronzing or a handful of dropped leaves after transit is normal. Expect roughly 30 to 50cm of height a year once established, and long term it can push past 10m, so 8m is the realistic figure over ten to fifteen years. Plants are delivered Australia wide, with delivery from $29.95. Advanced and large stock is freighted at cost, and every plant carries our 30 day healthy plant guarantee.

Plant care guides and related reading

• The complete guide to magnolia care in Australia
• Compare the full magnolia range
• Browse tall narrow screening plants
• Consider Little Gem Magnolia for a shorter screen

Common questions

How far apart should I plant it for a screen?

Two metres apart gives a continuous evergreen wall. For a driveway avenue where each tree should read separately, stretch it to 3m or 4m.

How narrow does it really stay?

About 3m across at maturity, and it holds that shape without shearing. If your bed is narrower than 2m, expect to trim the flanks occasionally rather than assuming the tree will do the work.

Can I keep it shorter than 8m?

Yes, with a reduction cut to the leader once it reaches the height you want, then light annual trimming. Repeated topping does thicken the crown and blur the clean columnar line.

How is it different from Little Gem?

Alta is taller and slimmer at roughly 8m by 3m, where Little Gem sits nearer 5m by 2.5m. Choose Alta to screen an upstairs window.