Monkey apple fruit: white, purple and magenta

Syzygium smithii is now classified as an unwanted organism (in forest and scrub) under the Biosecurity Act 1993. Photo / Getty Images

Lilly pilly or white monkey apple (Syzygium smithii; formerly Acmena smithii) is a summer-flowering, winter-fruiting evergreen tree that can live for more than 100 years and grow to about 15 metres.

Like pōhutukawa, rātā, mānuka, kānuka, feijoa and guava, it belongs to the myrtle family Myrtaceae.

The species became naturalised here in 1982 and is now classified as an unwanted organism (in forest and scrub) under the Biosecurity Act 1993. S. smithii is listed on the National Pest Plant Accord, meaning it is banned from propagation, distribution, and sale. These restrictions apply throughout New Zealand.

However, lilly pilly still grows in gardens because there is no mandate to remove plants that were in the ground before the species was identified as a pest.

Kererū and rosella eat the fruit and disperse the seeds. Seedlings establish in forest under low-light conditions and are difficult to remove.

I first encountered monkey apple in North Shore bush reserves where it forms dense thickets.

The genus Syzygium contains more than 1200 species globally.

New Zealand has one endemic species, S. maire (common names: swamp maire, maire tawhake), and several introduced species.

Some of these are distinct, like S. jambos (rose apple), which has large, pinkish fruits that look a bit like guavas but are more or less hollow. They smell and taste like rose water. This species is relatively uncommon in cultivation, as is S. floribundum (weeping lilly pilly, weeping myrtle, weeping satinash).

Two other species of Syzygium are common in NZ and are routinely used as hedge plants. These are S. australe (brush cherry, creek satinash, purple monkey apple), and S. paniculatum (brush cherry, magenta cherry, magenta lilly pilly). Both are native to Australia, like S. smithii.

At first glance, the flowers and foliage of these plants are quite similar. New leaves are red or purple, which is one of their attractions as a hedge plant. However, some differences separate them. S. australe has distinctive "pockets" just above where the leaves attach to the main branch on young branchlets. This is a good diagnostic character once you know what to look for.

Neither S. paniculatum nor S. smithii has these pockets. The fruits of S. smithii are usually white, whitish pink or pale purple, whereas S. australe and S. paniculatum fruits are magenta.

S. australe is particularly susceptible to myrtle rust, a deadly plant disease caused by the fungus Austropuccinia psidii. Plants are often found covered in yellow spores in summer when myrtle rust is most active. This increases the spore load in the environment and puts our native and economically important myrtles at risk of infection.

All three common Syzygium are often confused with one another, even by nurseries and avid gardeners. To add to the confusion, they are sometimes sold using overlapping and vague common names like lilly pilly, monkey apple and acmena.
For botanists, this is annoying. We like plant labels to be correct.
Plant names should always be written in italics with the first letter of the genus a capital letter and the rest lower case.

The ripe fruit of all lilly pilly species are edible and contain vitamin C.
On one of my recent walks, I found a mature tree in Springvale, identified it as S. paniculatum and started picking the low-hanging fruit with the permission of the property owner.

My delicious sugarless porridge with a pinch of turmeric and pepper has become more colourful.

The timber makes good firewood. It's a very heavy, wet wood that takes 18 months to two years to season.

Sources
https://bioheritage.nz/whats-in-a-name-demystifying-lilly-pilly-hedges/
https://www.nzpcn.org.nz/flora/species/syzygium-paniculatum/