Gadenin日本語Get the appGrafted or seedling decides your first crop
A grafted macadamia carries wood taken from a tree that has already proved itself, and it comes into bearing four to six years after planting. A seedling grown from a nut is a genetic lottery. It takes eight to twelve years to produce anything, and when it finally does, the nuts may be small, the shell may be thick enough to defeat a cracker, and the tree may crop only lightly for the rest of its life.
You can see the difference at ground level. A grafted tree has a union a few inches above the soil where the bark texture changes and the trunk often kinks slightly. If there is no union, you are looking at a seedling, whatever the label says.
Seedlings are worth planting only as a windbreak or as rootstock you intend to graft onto later. If you want nuts within the decade, plant grafted stock and accept the higher price.
| Tree type | First nuts | What to expect |
|---|---|---|
| Grafted, container grown | 4 to 6 years | Predictable nut size and shell thickness |
| Grafted, bare root | 5 to 7 years | Slower to establish, roots resent the move |
| Seedling from a nut | 8 to 12 years, sometimes never | Unpredictable quality, often very hard shells |
Site: warmth, drainage and shelter from wind
Macadamias are subtropical evergreens. They grow best between 60F and 85F (16C to 29C), slow down below 55F (13C), and young trees are damaged when the temperature falls to around 28F (minus 2C). An established tree tolerates a brief dip to about 25F (minus 4C) with scorched leaf edges, but a hard freeze kills the current season's crop outright.
Drainage matters more than fertility. The roots sit in the top eighteen inches (45 cm) of soil and rot quickly in ground that stays saturated. Dig a hole a foot (30 cm) deep, fill it with water twice, and if the second filling has not drained within four hours, plant on a raised mound eight to twelve inches (20 to 30 cm) above the surrounding level.
Wind is the other site decision. Macadamia wood is brittle and the root plate is shallow, so an exposed tree loses branches in a gale and mature trees blow flat. Plant on the sheltered side of a hedge, a fence or an existing windbreak if you have one.
Aim for slightly acid soil, roughly pH 5.0 to 6.5. Macadamias are poor at taking up iron and manganese from alkaline ground, and the leaves go pale and yellow between the veins as a result.
Planting without touching the root ball
The fine feeding roots of a macadamia are brittle and dense, and they do not recover from being teased out. Every instruction you have read about loosening a pot-bound root ball before planting is wrong for this tree. Slide it out whole, set it in the hole, and backfill.
- Dig wide and shallow Make the hole two to three times the width of the root ball and no deeper than it is tall. A deep hole settles, and the tree sinks until the trunk base sits in wet soil.
- Get the tree out of the pot in one piece Cut the pot away rather than pulling the tree by the trunk. Do not tease, comb or cut the roots. If the root ball falls apart in your hands, the tree will sulk for a full season.
- Plant at the same depth, never deeper The top of the root ball should sit level with the finished soil or half an inch (1 cm) proud of it. Soil piled against the trunk rots the bark and drowns the surface roots.
- Backfill with the soil you dug out Break up the clods and firm the soil gently with your hands, not your boot. Do not fill the hole with rich compost: a soft pocket in heavy ground fills with water and holds it.
- Water in once, thoroughly Soak the root ball and the backfill together to close the air gaps. Then water twice a week through the first dry season and let the surface dry between soakings.
- Mulch wide, not deep Spread a coarse mulch two to three inches (5 to 8 cm) deep out to the edge of the canopy, and leave a clear ring of four inches (10 cm) around the trunk itself.
Stake it firmly, and low
Most young trees are staked loosely on purpose, so the trunk flexes and thickens. A macadamia is the exception. Its top is heavy and evergreen while its root plate is shallow and slow to anchor, so a trunk left free to rock grinds a cone-shaped cavity in the soil, shears the new roots as fast as they form, and lets water sit against the collar.
Drive two stakes outside the root ball, on the two sides the prevailing wind runs between, and tie the trunk to both with a broad flexible strap at about a third of the tree's height. The tie should hold the trunk still, not merely catch it after it has swung. Check after every gale, and check that the strap has not begun to cut in as the trunk thickens.
Leave the stakes in place for two to three years, which is longer than you would for most fruit trees. Remove them once you can push the trunk hard at chest height and feel no movement in the soil at the base.
If you already have a leaning young tree, do not straighten it by pulling it upright against tension. Reduce the top by a third to cut the sail area first, then stake it firmly in the position it has taken.
Spacing and keeping the ground clear
A garden macadamia reaches twenty-five to forty feet (8 to 12 m) tall and nearly as wide if it is left alone, though most home growers keep them to fifteen feet (5 m) with light annual pruning. Plant well clear of paths and drives: the nuts drop to the ground when ripe, and you want to be able to sweep them up rather than pick them out of a border.
Two trees crop better than one. Macadamia flowers are visited by bees and cross pollination between two different grafted trees typically lifts nut set substantially, so plant a second tree of a different type within about thirty feet (9 m) if you have space for it.
| Planting situation | Spacing | Reason |
|---|---|---|
| Two trees for cross pollination | 20 to 30 ft (6 to 9 m) apart | Bees work between them, canopies stay separate |
| Single tree from a building | 15 ft (5 m) minimum | Brittle limbs, and roots dislike a dry rain shadow |
| From a path or driveway | 12 ft (4 m) | Falling nuts need clear, sweepable ground |
| Large container | Pot 24 in (60 cm) across | Expect a much smaller tree and a modest crop |
What to record on planting day
Write down the planting date, whether the tree is grafted or a seedling, and exactly where each tree stands. A macadamia takes years to declare itself, and by the time you are wondering why one tree crops and the other does not, the labels will be gone and your memory will be no help.
Note the drainage test result and the date the stakes went in, with a reminder two years out to check the ties. Trunk damage from a strap that was never loosened is one of the most common avoidable losses on a young macadamia.