Macadamia integrifolia aka Queenslandnut

Macadamia integrifolia is an evergreen tree grown for edible nuts. It belongs to the Proteaceae family. Its native range runs from southeast Queensland into northeast New South Wales. It grows in rainforests in eastern Australia. Growers also raise it in warm regions beyond Australia, including Hawaii. People use it as a crop, shade tree, and ornamental.

Garden trees reach 30–50 feet [9.14–15.24 metres] tall. Their spread ranges from 20–40 feet [6.10–12.19 metres]. Growth is slow, and the crown becomes dense and broad. Trees may have more than one upright trunk. Glossy green leaves stay on the tree throughout the year. Each simple leaf has a long, oval or lance-shaped outline. The edges have slight waves rather than deep cuts. Leaves grow in whorls, most often in groups of three. They reach about 0.67–0.83 feet [0.20–0.25 metres] long.

Small, scented flowers open in winter and spring. Their colour ranges from white to a pale pink tint. They hang in narrow racemes from the leaf axils. These clusters reach about 0.67 feet [0.20 metres] long. Bees visit the flowers and help pollinate them. Green husks wrap the nuts as they grow. Each husk holds a smooth, hard shell around a cream-coloured seed. Harvest comes in summer, according to North Carolina State Extension. Trees begin to bear fruit at six or seven years old.

Give this tree full sun and rich soil that drains well. It prefers moist ground with plenty of organic matter. Young trees need ample water, while older trees can withstand drought. Steady rain suits it better than long dry spells. Protect the tree from strong winds and frost. Missouri Botanical Garden lists USDA zones 9–11 for outdoor growing. North Carolina State Extension also includes zone 12. In cold regions, pots allow growers to move trees into greenhouses. Its broad crown gives shade, and its flowers add seasonal interest.

People eat the seeds raw or cooked and grind them into flour. They also use the seeds in cakes and ice cream. The seeds yield edible oil, which also has cosmetic uses. Hard shells can serve as fuel, and rotted husks enrich potting mixes. No medicinal use is recorded in the supplied evidence. Missouri Botanical Garden reports no major pest or disease problems. Yet fungal flower blight has affected trees in Australia. The nuts are food for people but toxic to dogs. Signs in dogs include weakness, vomiting, tremors, and depression. The substance that causes this poisoning remains unknown.