how-do-macadamia-nuts-grow

How Do Macadamia Nuts Grow? Slowly — But They’re Worth the Wait!

As natives of northeastern Australia's rainforests, macadamia trees (Macadamia spp.) thrive in frost-free climates with plenty of rain and cool coastal breezes to temper summer's heat. In the right conditions, they begin producing nuts in five to seven years while doubling as lovely, evergreen shade trees. If you supply those conditions, the biggest challenge to growing them will be cracking their shells!

Where Do Most Macadamia Nuts Come From?

Today, Australia leads the world in commercial macadamia production followed by:

  • South Africa
  • Hawaii
  • Central America
  • New Zealand
  • Coastal California
  • Central and south Florida

USDA Hardiness Zones

In the U.S., macadamia trees grow in the parts of USDA plant hardiness zones 9 through 11 that meet their climate requirements. Elsewhere, container growing is an option as long as you have a sunny indoor location for overwintering a sizeable tree.

How Macadamia Nuts Grow

Like almonds and pistachios, macadamia nuts are the seeds of fruits classified botanically as drupes. All drupes consist of three layers:

  • The exocarp, or fibrous outer husk .
  • The mesocarp, or pulpy flesh.
  • The endocarp, or hard shell protecting the nut.

How Macadamia Drupes Develop

From mid-winter to early spring, a mature macadamia tree bursts into bloom with cascades of sweetly scented flowers. After being pollinated by bees or wind, each bloom cluster typically yields from one to 20 drupes. By harvest time, the drupes’ green outer husks have split along one side to release hard-shelled inner nuts. The nuts drop from the trees as they ripen.

Harvest Timing

In the Northern Hemisphere, most macadamia nuts ripen between between late fall and early spring, depending on location and tree cultivar. Because nuts on the same tree mature at different rates, completing a harvest may take from six to 12 weeks.

Macadamias for Home Gardens

Two tree species — Macadamia integrefolia and Macadamia tetraphylla — account for all commercially grown macadamia cultivars. Two cultivars stand out as home garden choices:

  • ‘Beaumont’ puts on a late-winter show with glossy, coppery-pink leaves and pale-pink flower clusters. Standing 15 to 20 feet tall with an upright, rounded canopy, it features a lengthy harvest of very large nuts.
  • ‘Vista’ is a pyramidal, medium-sized tree prized for nuts with shells thin enough to succumb to an ordinary nutcracker. Even better, it yields a harvestable crop in just three years.

By their 10th harvests, most macadamia trees yield from 30 to 60 pounds of nuts per harvest. That rises gradually as they age — and many produce for a century or more!