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YOUR GARDENING QUESTIONS THIS MONTH

Your questions answered.

QLONG LIVE DAFFS

I used to plant daffodil bulbs each autumn. They’d flower furiously the following spring but as each year passed they would dwindle. Nearby there’s a daffodil patch that has lasted for years but no-one knows the variety. Which daffodils will keep growing in Auckland without chilling? DOMINIC TOON, AUCKLAND

APaul Hoek from NZ Bulbs says most daffodils should grow well in Auckland. Sometimes in warm locations the double daffodils can fail to open their buds, but the single daffodils are usually quite reliable. One variety Paul recommends as a healthy, strong grower is ‘Carlton’, a yellow trumpet variety which does very well in long term plantings in all areas of New Zealand.

Daffodil patches can become infested with narcissus fly, which lays its eggs at the leaf bases in spring. The grubs hatch and burrow down into the bulbs where they can eat out the centre of the bulb, right where the developing flowerbud is located. This is more of a problem in sheltered areas as the narcissus fly are fairly lazy and don’t like windy locations.

Other reasons for daffodils failing to flower in following seasons are overcrowding (lift, separate and replant every 3-4 years) or not letting the foliage die down naturally. If the foliage is cut off early or tied into a bundle for neatness, the leaves can’t photosynthesise to build up the energy reserves needed for flower formation within the bulb for the next flowering season.

Barbara Smith

QWHITE GRASS

During the wetter months, I get small patches of strange white grass that last a couple of days. They appear on the shadier front lawn, but not on the back lawns. What is it? STEVE TAYLOR, CHRISTCHURCH

ATurf expert John Tutt from Newton Seeds identified the white patches on your lawn as slime mould – a quite common occurrence in lawns. It’s not a bad problem and certainly not one to make an urgent dive for the sprayer over.

Slime moulds share some characteristics of fungi and single celled organisms. The white coating on the grass is made up of the spore producing bodies of the slime mould and can appear suddenly overnight. They can be various colours but are most commonly grey, purplish-brown or white.

The spore structures are fragile and won’t hurt the lawn – they are just using the grass as a host to park up for a while. Slime moulds don’t eat plants. Instead, as single-celled amoeba-like organisms, they engulf microscopic bits of organic material like bacteria. Environmental conditions like lack of nutrients trigger spore production. They’ll often vanish spontaneously or you could wash them off with a strong jet from the hose or cut the lawn short over winter to deter them.

John also recommends scarifying the lawn thoroughly to remove all the thatch and dead material that’s visible to reduce the risk of other diseases getting a foothold in there. Once the weeds start growing again send them packing as well.

Barbara Smith

QMYSTERY FRUIT

We’ve had these trees for some time but the labels have faded. One has fruit (about 10mm across) for the first time. There are spikes on some of the branches. What are they? CORNELIA ROL, WAIUKU

ATree crops expert Sheryn Dean has identified your fruit as tropical apricots. The variety available in New

Zealand is a hybrid between two types of dovyalis: the Sri Lankan gooseberry or kitembilla ( Dovyalis hebecarpa) and its close relative the Ethiopian kashun ( Dovyalis abyssinica). Both these parents are seriously thorny shrubs with seriously sour fruit, but their offspring, a natural hybrid that popped up in a Florida garden about 50 years ago, is much more friendly to both skin (with only a few spines scattered in random clusters along its branches) and palate.

In September 2014, our Northland columnist the late Russell Fransham said you can pick ripe fruit from it almost every day of the year, but it has two main flushes of fruit: in spring and again in autumn. In good soil it grows pretty fast initially, preferring similar conditions to citrus, but if frosted it defoliates, especially when young. If left unpruned the tropical apricot bush can grow up to 5m high. If you don’t have room for this, they make a terrific container plant,and will fruit prolifically from an early age when the roots are constricted. A regular dose of rose fertiliser will encourage the fruit to keep coming in a steady stream.

The intensely tart fruit freezes well and makes delicious cocktails, desserts, chutneys and curries.

Barbara Smith

QIS IT A MUTANT? I found this grapefruit under our tree. It looks as if each segment has developed separately. What would cause this? Can anything be done to prevent it happening again?

ALAN DOUBE, HAMILTON

AThis grapefruit developed this unusual shape because the flower was infected by citrus bud mites, Aceria sheldoni.

The tiny mites – only 0.15mm long are a pest worldwide and are found on all varieties of citrus. Grapefruit and mandarins are usually less likely to be infected than other citrus varieties like lemon and navel oranges.

There can be up to 100 minute mites within a leaf or flower bud. They feed by puncturing the cell walls to access the contents. The foliage and flowers develop abnormally with thickened cell walls and deformed shapes. When the fruit start to develop the mites puncture the cells of the rind so the fruit becomes distorted as it grows. Apart from direct damage by the mite, the gaps and crannies in the fruit provide shelter and entry points for other pests such as spider mites and mealybugs.

Healthy, well-fed and evenly watered trees are better able to resist build up of mite populations.

Control small infestations by removing damaged leaves and deformed fruit as soon as you spot them. Burn or put infected material in the rubbish rather than composting it. Avoid spraying as predatory insects that eat the mites will be killed too.

For severe infestations, try Yates Nature’s Way Citrus, Vegie and Ornamental spray, Conqueror Oil or Grosafe Enspray 99.

Barbara Smith