Trees for small backyards: what actually fits

The most expensive mistake in a suburban garden is a tree that was the right size in the pot and the wrong size in ten years. Removing an established tree costs more than the tree, the planting and a decade of care combined, and the damage it does to paving, pipes and footings first costs more again.

This guide is about avoiding that. Not by planting nothing, but by choosing the species that stay in scale, and putting them in the right place.

Measure the gap, not the tree in front of you

Take a tape outside before you take a card out. Three numbers decide most of it: the usable width of the bed, the clear distance from the planting point to the nearest wall, and the height under wires and eaves.

Width matters more than height in a small yard. A tight column fits a 1.5m side passage where a rounded head of the same height will not, and pruning will not convert one into the other.

Decide what the tree is for

Most small gardens fit one tree, and the jobs it might do pull in different directions.

• Shade over a seating area. A spreading head lifted to about 2.2m so people walk under it. Deciduous suits the north side, where winter sun has to get back through.
• Blocking a window or an upper storey next door. Height with almost no width, on a single leader, and usually a row rather than one specimen. See screening a narrow space.
• A focal point seen from inside. Bark, branch structure and flower matter more than canopy area, and a weeping or multi-stemmed plant earns the most per square metre.
• Fruit. Full sun and access from every side for picking and netting, so it goes in the open, not the corner.

Setbacks that save you money

A working rule: plant at least half the tree's eventual canopy width away from any structure. A 4m spread goes 2m clear of the wall, minimum, and double that for vigorous roots. Keep clear of the sewer and stormwater line, the pool shell and its plumbing, and the slab edge. If you do not know where the pipes run, a plumber's camera is cheaper than a removal and a repair.

Keep the large gums well away from all of it. Hill's weeping fig and the native figs in the figs and ficus range belong in a big garden or a root-barriered planter, never beside a pool shell.

Matching the form to the gap

Crowns thicken with age, so a row planted tight knits into one wall whether you meant it to or not.

The trees that genuinely stay small

Deciduous, for seasonal change and winter sun

Japanese maples lead the list in cool districts, and the weeping laceleaf forms are the smallest. Inaba Shidare cascades from the graft into a layered mound and holds its purple red far later into summer than most dissectums.

Crepe myrtles carry flower right through the hottest part of summer. Acoma is one of the smaller spreading selections, white flowered, with a low almost horizontal frame that often finishes wider than it is tall, and it takes reflected heat off paving. Tonto is a semi-dwarf multi-stemmed form in fuchsia red that stays in proportion under power lines. Both carry mildew resistance from the indica by fauriei crosses.

Forest Pansy breaks rosy purple flower straight from bare branches before any leaf appears, then opens maroon heart-shaped foliage that fades to bronze green in heat.

Evergreen, for structure and screening

Compact magnolias hold a boundary all year, and Little Gem and Teddy Bear are the two specified for it. The Water Gum sold as Luscious carries broader, thicker leaves than the straight species, enough to read as a screen rather than an open small tree, over mottled cream and orange bark. Smaller lilly pilly selections do a similar job, and olives suit dry sunny gardens.

Natives that behave in small spaces

Grafted flowering gums changed what is possible in a front garden. Baby Orange carries dense orange heads on a small rounded tree, and the graft is the point: seedling ficifolia is unreliable on the east coast, and a named selection on tougher rootstock is what makes it work in Sydney or Melbourne soil.

Sentinel is the columnar coast banksia, feeding honeyeaters through autumn and winter when little else does. Tree-form bottlebrush works in the same beds. From the kurrajong group, Brachychiton bidwillii is the small one: shrubby, multi-stemmed, with a swollen woody base, and it trains into a compact tree. Sweep the seed capsules up with gloves, and keep them out of play areas: the fine hairs inside itch on skin and in eyes.

Districts change the shortlist

The same tree is a different proposition in Bundaberg and in Bowral.

• Humid subtropical east coast. Brisbane and the northern rivers punish anything prone to mildew or scorch. Japanese maples struggle. Water gum, lilly pilly and the grafted flowering gums are on firmer ground.
• Melbourne and the basalt clay of the west. Winter waterlogging is the killer, not cold. The water gum handles ground that stays wet better than most, but mound the bed anyway: see planting into clay.
• Cool tablelands, Adelaide Hills, Southern Highlands, inland Victoria. Maple country, and cold autumn nights are what make an ornamental pear colour properly.
• Perth and the calcareous coastal sand. Sentinel takes thin sandy soil and salt-laden wind. Both compact grandifloras, Little Gem and Teddy Bear, dislike limey ground, where the leaves go pale between the veins and the plant sulks for years. Brachychiton bidwillii does well here.
• Frost country such as Orange. Grafted ficifolia is a gamble. Deciduous is the safe answer.

Choosing between the evergreen boundary trees

These four look interchangeable in photographs and are not. Little Gem is narrower, more upright and more open, so it is the one to pleach or run along a fence in a 2m bed. Teddy Bear is denser and reads as a solid mass, better as a pair either side of an entry. Both are slow, so buy near the size you want. The water gum is faster and makes a tidy upright rounded head, not a column, so it needs the 3m bed. Sentinel is narrowest, but narrow does not mean small: allow for a full tree trunk at the base, and keep high-phosphorus lawn fertiliser off its roots.

Shapes that buy you space

Where the footprint is truly tight, shape rather than species solves it. Standards, a clear trunk with a lifted canopy, let you plant beneath and walk under. Espalier flattens a tree against a wall to almost no depth and works well with citrus: an Eureka Lemon on wires 300mm off a north wall takes a strip barely wide enough to kneel in. The topiary and standards range covers the trained shapes.

Large pots are a permanent solution rather than a compromise. A 500mm pot holds roughly 69 litres of mix, enough for a small tree watered properly. See growing in pots.

Getting it in the ground

Dig wide and no deeper than the rootball, and resist filling the hole with bought soil, which makes a bathtub the roots never leave. On clay, mound instead of digging down. Keep the graft union above the finished soil line on anything grafted, which covers the flowering gums, the citrus and every Japanese maple, and rub off shoots from below it as soon as they appear.

Water deeply and less often than instinct suggests. In a small yard the temptation is to plant everything else at once. Resist it for a season, because a new tree competes badly. The full sequence is in planting an advanced tree.

What goes wrong

• Pear and cherry slug. The main failure on ornamental pears. A shiny sawfly larva grazes the upper leaf surface and leaves the canopy skeletonised and brown by midsummer. Hose it off with a strong jet at first sight, and expect a second generation.
• Topping a crepe myrtle. Cutting to stubs leaves permanent knuckles and whippy growth that flops under the flower heads. Thin lightly instead: crepe myrtle pruning.
• Scorch on a laceleaf maple. Hot dry wind and afternoon western sun burn the fine leaf margins, and a burnt dissectum stays burnt until next season's flush.
• Wet feet. A grafted flowering gum in a lawn hollow, or a bidwillii in heavy clay, rots at the collar over a wet winter and does not come back.
• Root disturbance later. Forest Pansy resents it. Plant it once, then keep spades and cable trenches out of the root zone.
• Litter you did not plan for. Teddy Bear leaves are leathery and slow to break down, so keep it off pool paving and pebble beds. Olive fruit stains paving.

What to plant underneath

Bare mulch under a deciduous tree looks bleak for five months. Keep the underplanting low and tolerant of root competition. Lomandra and liriope hold a clean line and take dry shade. A low clipped run of box reads well in winter when the tree above is bare, though box leaves are toxic if eaten, so think twice where a toddler or a chewing dog is about. Keep a metre clear around the trunk: planting pushed to the stem holds moisture against the bark and invites collar rot.

Buy the size that suits the wait

Small trees establish faster and cost less. Advanced stock gives you the garden now, and in a small yard that is often the sensible purchase, because one tree is doing all the work. See advanced trees, and what advanced actually means for the size definitions. Access is the thing people plan last: a 200L tree does not fit through a standard side gate, so check the path from truck to hole before you order.

Browse the wider range in feature trees. Every order ships farm-direct with flat $99 delivery in QLD, NSW, VIC, SA, ACT and WA, a $399 minimum order, and the 30-Day Healthy Plant Guarantee.

Related ranges: Crabapples, Flowering cherries and blossom trees, Topiary and standards, Cercis and Forest Pansy.

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