The Back Yard

Justin Newcombe's tips for creating a gorgeous and productive garden

Justin Newcombe: Fruity dilemmas

By Justin Newcombe

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Landscape gardener and Life columnist Justin answers your questions

A spray may save ailing passionfruit vines. Photo / Thinkstock
A spray may save ailing passionfruit vines. Photo / Thinkstock

Q: I have an avocado tree that is around 10 or 11 years old and has been bearing fruit for the past three or four years. Not sure what breed, they're not hass, as the skins don't go black, or reed, as the skins aren't smooth and shiny. Fuerte maybe? It was in flower in September/October and I'm wondering how long the process from fruit-setting to maturity should take? I have found past crops are very thin skinned, the fruit is watery, tasteless, and almost sour, and the seed inside is dried and loose inside the fruit. If I leave them on the tree, either, the birds start pecking at the bottom of them, or the ends go black. Also, sometimes the flesh inside is "thready"and goes black easily. Basically , I need to know when to pick them. - Many thanks, Sheridan

A: I think your avocado may be a fuerte. These have poorer keeping qualities than both the hass and the reed. To improve the fruit, dress the tree with blood and bone as well as a good dose of compost. Mulch and keep well-watered. Also look at pruning the tree to open the canopy. This will allow more light on to the fruit. I would also suggest removing some of the young fruit to improve the quality of the remaining fruit.


Q: We have a passionfruit problem we are hoping you can help with. We inherited an established passionfruit vine when we moved to our house in March this year. We harvested lots of fruit and even gave some away to friends. It survived very well in the winter - few leaves fell off and the vine stayed green. We were expecting another good season, however, in mid to late September the leaves started to turn yellow and fall off and the vines withered as well. It looks like it is dying. But there are parts where you see new leaves shooting out. We have put some Thrive Granular Citrus Food and sheep pellets around the root in September. Does that have something to do with the vine suddenly becoming ill? Or is it some disease? - Sarah Liu

A: Sound like last year's crop was a lot to live up to. There are many things which could be affecting your vine. Firstly passionfruit require lots of watering but also good drainage is essential. So make sure the roots have lots of good quality mulch and compost around them and that the soil is not a clay-type soil and holding too much water. Because the vine was so prolific last year it may need a jolly good feed, so dress it with blood and bone and water in a cup of magnesium sulphate diluted in a 10-litre bucket of water. Another possibility is your vine could have a virus spread by sucking insects like psyllid or a bad infestation of white fly. Try spraying your passionfruit with a baking soda and oil spray (1 Tbsp each of of baking soda, olive oil and garden-friendly dish soap, mixed in a litre of water). Make sure you spray under the leaves especially and repeat spray every 10 days. If your passionfruit hasn't recovered it may have a viral or bacterial infection, in which case I would remove it, ASAP.


Q: We live in an apartment with a sizeable planter box on our terrace. Last year we successfully grew tomatoes, runner beans, silverbeet, parsley and sweet basil. That is until one morning we awoke to find the beans and basil were completely destroyed and the silverbeet looking sad. A street light shines directly on to our terrace and it seems likely night moth is the culprit. We were destroying at least 20 caterpillars every day for some time. Covering the planter box could be a problem because the wind would likely lift it off. The sprays that have been suggested to us are Egmont's Beat-a-Bug Insect Spray and/or Yates' Mavrik Insect and Mite Spray. We would welcome your advice please. - Shirl

A: Try covering the pots with a microfibre, which is a fine mesh fabric. This will stop the butterflies landing on your pots. Also try moth traps, which are yellow plastic squares and in a confined space like yours will do a good job. I have heard that you can suffocate the caterpillars with flour. I'd be really interested to see if it works. Do try it and report back to us, please.


Do you have a gardening, DIY or landscaping question for Justin? Email gardening@nzherald.co.nz with your question and we will be happy to answer it in our pages

- NZ Herald

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