Macadamia care guide: when & how to prune, fertilize and spray
Macadamia integrifolia / M. tetraphylla · USDA zones 10–11
Evergreen subtropical tree with rich, buttery nuts in rock-hard shells. It's frost-tender when young and grows best in mild, frost-free coastal climates. Self-fertile, but crops more heavily with a second variety nearby. Bears from about year 5. Macadamias are sensitive to phosphorus, so use low-phosphorus fertilizer.
☀️ Sun
Full sun; shelter from strong winds, as the branches are brittle.
💧 Water
Regular deep watering, especially while nuts fill. Mulch heavily: the roots are shallow.
🪱 Soil
pH 5.5–6.5. Deep, well-drained, rich in organic matter. Thick organic mulch. Avoid high-phosphorus fertilizers and bone meal.
How and when to prune macadamia
Light prune after harvest
When: from the last spring frost to 6 weeks after.
- zones 8–10: about Feb 25 – Apr 8
Macadamias need little pruning. Training young trees to a central leader prevents weak, splitting forks.
- Young trees: keep one central leader and remove competing vertical shoots.
- Remove dead, crossing and very low branches.
- Thin dense growth lightly for airflow.
Tools: Bypass pruners, Loppers
Fertilizing macadamia
Low-phosphorus feeding
When: 2–4 weeks after the last spring frost, then every 12 weeks (3 times a season).
- zones 8–10: about Mar 11–25
Macadamias have special 'proteoid' roots that take up phosphorus so well that normal fertilizers can burn them.
- Use a low-phosphorus fertilizer such as a native-plant or citrus feed (middle number 3 or less) at the label rate.
- Water it in well. Keep mulch thick and replenish it.
What to use: 🌿 Organic citrus food (e.g. Espoma Citrus-tone 5-2-6) · 🌿 Finished compost or composted manure · Low-phosphorus native-plant fertilizer (e.g. 10-2-6)
Caution: Never use bone meal, superphosphate or 'bloom booster' fertilizers on macadamias.
Soil, compost & mulch for macadamia
Refresh mulch
When: 2–6 weeks after the last spring frost.
- zones 8–10: about Mar 11 – Apr 8
Mulch keeps roots cool and moist, suppresses weeds and slowly feeds the soil. Applying it after the soil warms lets roots wake up first.
- Spread 2–3 in (5–7 cm) of mulch over the root zone.
- Keep mulch 2–3 in (5–7 cm) away from stems and trunks. Mulch piled against bark invites rot and rodents.
- Don't go deeper than 3 in (7 cm) in total. Too much mulch suffocates roots.
What to use: 🌿 Shredded hardwood or pine bark mulch
Frost & winter protection for macadamia
Frost protection for young trees
When: from 1 week before to 2 weeks after the first fall frost.
- zones 8–10: about Nov 24 – Dec 15
Young macadamias are damaged below about 28°F (−2°C).
- On frost nights, cover young trees with frost cloth to the ground and water dry soil beforehand.
Other care for macadamia
Collect fallen nuts
When: from 4 weeks before to 8 weeks after the first fall frost, then every 8 weeks (2 times a season).
- zones 8–10: about Nov 3 – Jan 26
Macadamias drop when ripe, over several months. Collect them weekly before rats, mold or sprouting.
- Gather fallen nuts every week. Remove the green husks within a day or two.
- Dry the in-shell nuts for 2–3 weeks before cracking them with a macadamia nutcracker or a vise. A regular nutcracker won't work.
- Dry nuts in a single layer in a warm, airy, shaded spot (or mesh bags hung indoors) for 1–3 weeks until the kernels snap rather than bend.
- Store dried nuts in the shell in a cool, dry place, or shelled in the fridge or freezer. Shelled nuts go rancid at room temperature.
Common macadamia problems and how to fix them
Frost damage
Signs: Young leaves and shoots blacken below about 28°F (−2°C).
What to do: Cover young trees with frost cloth. Mature trees tolerate brief light frost.
Phosphorus toxicity
Signs: Yellowing and leaf burn after feeding.
What to do: Use low-phosphorus, slow-release feeds. Never use bone meal or 'bloom' fertilizers.
Rats
Signs: Gnawed nuts under the tree.
What to do: Harvest fallen nuts promptly and keep the ground clear.
Root rot
Signs: Decline in wet soil.
What to do: Plant only on well-drained sites.
Macadamia care FAQ
When should I prune macadamia?
Light prune after harvest: from the last spring frost to 6 weeks after (around Feb 25 – Apr 8 in zones 8–10). Evergreen subtropical tree with rich, buttery nuts in rock-hard shells. It's frost-tender when young and grows best in mild, frost-free coastal climates. Self-fertile, but crops more heavily with a second variety nearby. Bears from about year 5. Macadamias are sensitive to phosphorus, so use low-phosphorus fertilizer.
What is the best fertilizer for macadamia?
Macadamias have special 'proteoid' roots that take up phosphorus so well that normal fertilizers can burn them. Good options: Low-phosphorus native-plant fertilizer (e.g. 10-2-6); Organic citrus food (e.g. Espoma Citrus-tone 5-2-6); Finished compost or composted manure.
What soil does macadamia need?
Deep, well-drained, rich in organic matter. Preferred pH 5.5–6.5. Thick organic mulch. Avoid high-phosphorus fertilizers and bone meal.
How much sun and water does macadamia need?
Sun: Full sun; shelter from strong winds, as the branches are brittle. Water: Regular deep watering, especially while nuts fill. Mulch heavily: the roots are shallow.
What are common macadamia problems?
Frost damage: Young leaves and shoots blacken below about 28°F (−2°C). Cover young trees with frost cloth. Mature trees tolerate brief light frost. Phosphorus toxicity: Yellowing and leaf burn after feeding. Use low-phosphorus, slow-release feeds. Never use bone meal or 'bloom' fertilizers. Rats: Gnawed nuts under the tree. Harvest fallen nuts promptly and keep the ground clear. Root rot: Decline in wet soil. Plant only on well-drained sites.
More nut trees care guides
Timings are given relative to your average frost dates, with examples for typical US climates. Always read and follow product labels.