The first stage in the development of a macadamia nut is flowering. During August and September trees produce masses of small flowers in long bunches called racemes. Macadamia integrifolia flowers are cream coloured, while Macadamia tetraphylla flowers are pink. During flowering, a range of animal species including bees, flies, ants, beetles, moths, butterflies and birds will visit the flowers in search of food (pollen or nectar). In doing so they will transfer pollen from the flowers of one tree, to flowers of a different tree. This is called cross-pollination and is essential for the development of good nuts.

Once pollination has occurred, the ovary at the base of the flower will start to swell as it starts to form into a nut. In the early stages, the small nuts are referred to as “nutlets”. Not all flowers or nutlets will grow to maturity. Many are shed by the tree, based on the resources (i.e. water) available. From October the nutlets continue to grow and by late December they have reached their maximum size. At this point however, they still haven’t developed their hard shell, so they are very attractive to sucking insects, particularly the Fruit Spotting Bug.

During January and February the shell hardens and oils accumulate within the kernel (the bit that we eat). From March to September, depending on the variety, the nuts reach maturity and drop off the tree. It is at this point they can be harvested.