Your Gardening Questions Answered - January

Your Gardening Questions Answered - January

There’s always something going on in the garden and if you come across a problem – we’re here to help!

We love hearing about your garden in our Garden Forum and are happy to answer any questions you may have, whether it be about insects, disease, plant varieties or planting advice.

Here are some of our most viewed questions from the past month. Have a read, you might just learn something new!

When is the best time to prune feijoas?

The best time to prune a feijoa tree is after it has finished fruiting. Prune on a dry day to limit the chance of fungal infections. You don’t have to prune every year but prune to allow enough space for air flow and to let the birds pollinate the fruit and for sunlight to get through.

What spray should I use to get rid of a heavy infestation of woolly aphids?

There are many options available to control woolly aphids. We recommend Grosafe Enspray 99 spraying oil. It is a certified organic spray.

Mix the spray according to the label on the bottle. Spray in the evening or early in the morning as it is less harsh on the plant then in the middle of the day. Spray the whole plant including the undersides of leaves. This should fix the problem.

WCoffee groundshat can I use coffee grounds on?

These can be used as a mulch, in your compost bin, worm farm or Hungry Bin. They can be mixed with potting mixes (in low quantities) or just mixed in your soil to improve the general health of the soil.

We have recently got ourselves an olive tree. Do you have any advice or tips on how to best grow an olive tree? Also, are there any sprays for protection we need to use or specific fertilisers needed?

The best way to prevent insects and diseases on any plant is to have a healthy plant, to do this, olives like well-draining soil and don’t mind a bit of a breeze.

We would recommend the use of organic fertilisers (seaweed, compost tea, fish fertiliser) to enhance and improve the overall health of the soil (i.e. more worms) as artificial fertiliser tends to kill the worms and hence does not improve the overall health of the soil. Maybe a combination of both e.g. slow release fertiliser only gets applied every 3-6 months while organic fertiliser is applied every month.

My passionfruit vine is loaded with fruit but some have a spot on them. They shrivel up and drop off the vine. What should I do?

Passion vine hopperSounds like you might have Passion Vine Hoppers on your plant. These are moth like bugs that lay eggs that look like little bits of white fluff.
Check your plant, and if you find any use Debug Diatomaceous Earth. This product is organic so it’s fine to dust over the fruit as well as the leaves.

For more tips on growing passionfruit, check out our video guide

What can I use to spray for white fly on my citrus trees? I have never had this problem before until now.

Recommendation for white fly on citrus is Enspray Oil. White fly have an extremely quick life cycle so will require 2-3 sprays relatively quickly after each other (over 14 days). A general spray programme for citrus is spray alternately every 4 weeks with Free Flow Copper then Enspray Oil in the middle. At this time of the year, give them a treat with an organic liquid fertiliser (compost tea, fish fertiliser or seaweed fertiliser) this way your citrus should always be clean of fungus and insects. All sprays mentioned are BioGro certified so safe to use on edibles but don’t spray during hot sunny days.

We have a Luisa Plum Tree that we bought with us when we shifted house. We have lost a lot of fruit with the high winds we have had recently. The fruit still seems to be dropping even as it is getting bigger. Is the tree lacking in something? We keep it well watered and has good drainage.

Luisa plumIf you have shifted this year, then we would suggest the shift, wind and general stress is causing the fruit drop. The tree will only carry as much fruit as it is able to maintain and will drop off the weaker ones.

Ensure it only gets deep watering when really required. To reduce the stress, spray on a liquid organic fertiliser such as seaweed, compost tea or fish fertiliser. You could also do a diluted spray with Enspray Oil but don’t spray during hot sun. This will help with preventing evaporation during stressful times such as high winds.

I have 8 young avocado trees, and on the 2 Hass (on Zutano) ones there is a small area on a branch that has white growth on it. Under that is a brown discolouration with evenly spaced dots in the bark. I’d love to know what this is and what to do about it.

It sounds like a few of your avocados have a fungus problem. You can cut the infected branches out if it is not affecting too much of the tree. Spray the whole tree with a liquid copper to control the fungal infection.

Things to check and adjust:

  • Make sure the soil is free-draining.
  • Adding compost and mulching improves the soil.
  • Fertilise regularly so the plant in getting what it needs.
  • Try not to overhead water and instead water at the base as overhead watering spreads fungal diseases.
  • Keep the area free of damaged or diseased branches.

I have a few citrus plants and also a hedge that has black soot on the leaves… just wondering what I can do to treat it?

The black soot that you see on the citrus and hedge is a sign that you have an infestation of insects. It is a type of fungus that grows on the sugary excretions of these insects. The insects could be either scale, whitefly or aphids or any other sap-sucking insect. The sooty mould itself is generally not a big problem but it is unsightly, the insect infestation will soon cause the plants to lose vigour.

Once you treat the plants for insects it should cure your problem, The sooty mould will soon subside.

Spray with an insecticide such as Grosafe Enspray 99 spraying oil. It is a certified organic spray. Mix the spray according to label instructions. Spray in the evening or early morning when it is not so hot. Spray the whole plants as best you can including as much as the undersides of leaves as you can get. Repeat the procedure in a few weeks time if needed.

This should fix the sooty mould issue!