Plant Doctor Archive

Spotted pittosporum

WE planted a new hedge last autumn of various types of pittosporums and they are growing like wildfire. But two of them look like they have a mould and black spot. What should I do?

ALTHOUGH the leaves you sent were dry and rather shrivelled, the problem looks typical of the kind of leaf spotting found on some pittosporums, especially lemonwoods (Pittosporum eugenioides). But the good news is there should be nothing to worry about.

This type of spotting is usually caused by insects, such as aphids or psyllids, feeding on new growth. As the insect population dies off in winter, the problem should cease and when you next trim the hedge you'll probably remove much of the spotted leaves, which will encourage healthy new growth.

Pittosporums can usually tolerate pest infestations with no need for spraying. Check them next spring and summer and trim off any affected shoots.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.