SOME GARDEN CONUNDRUMS ANSWERED
GARDENERS ASK THE BEST QUESTIONS
THE most satisfying aspect of being a horticulturist is the great feeling of satisfaction when able to solve any of the many gardening problems presented by enthusiasts such as Carnival gardeners, vegie growers, gardening talkback listeners, and plant collectors.
Now not all problems can be solved, but, rest assured, I’ll give it a good go, and in the process, learn more about plants than I did the day before.
Let’s take a squiz at a few questions from fellow gardeners over the last few months, and some possible solutions.
MARGARET asked about using fungicides on her roses. She had heard that some types could burn plant foliage if used incorrectly.
The main culprit for causing leaf burn is lime sulphur.
This fungicide should be applied immediately after the winter pruning of roses, when the plant is without leaves.
If lime sulphur is applied to soft, new rose leaves (i.e. applied too late), it will likely burn and damage the tender new growth.
BRETT wanted to know about repotting citrus trees.
What’s the best potting mix, and how to repot into the same size container?
By far the best potting mixes for citrus trees are any of the premium mixes containing a high percentage of peat or coir fibre, as well as a long-term controlled release fertiliser (8-12 months).
To repot into the same container, remove the tree from the pot, tease the old, broken down potting mix from the bottom of the root ball, then partly fill the bottom of the pot with the new mix.
When repotting the plant, remove a little mix from the sides of the root ball, place the plant into the pot (keeping the top of the root ball a few centimetres below the top of the pot), and refill with new mix around the sides of the root ball. Water in with a weak seaweed solution.
PHIL was concerned about mistletoe plants in some of the native trees around his property.
He’d heard that they may eventually kill the trees.
The simple answer to this is that mistletoe may well eventually kill a tree that it has parasitised, but it could take many years to do so.
A tree that has been weakened by disease or drought may well succumb to a large infestation of this intriguing plant.
A small clump of mistletoe could theoretically be removed from a plant to “save” it, but in many cases the culprit will reoccur.
Many mistletoes attract native birds to the garden.
SANDRA wanted some information on whether adding wood ash to the garden was beneficial or detrimental to the soil.
In most cases, the addition of wood ash to your garden beds will be beneficial.
Wood ash is fairly high in potassium, an essential element for flower and fruit production, so the greatest benefit will be seen in the vegie and fruit tree garden.
It will also help to hold nutrients and water in a soil.
However, be careful not to over-apply to a garden, as it is about half as alkaline as garden lime, so it will raise the pH over a period of time.
For those living on alkaline black soils, it’s best used in the compost heap to reduce acidity.
BRIAN had a problem with scale on his citrus trees.
A steady stream of ants up and down the stems and trunk is a sure sign of these little sap suckers, and a large infestation can easily reduce a small tree’s vigour.
Scale can be treated with a range of organic remedies, including dousing with soapy water, but by far the best treatment is a spray with a plant-based oil product derived from tea-trees and eucalyptus.
BEVERLEY wanted some information on treatment for azalea lace bug.
A sure sign of azalea lace bug (ALB) is a silvering of the upper leaf surfaces, and small brown and black spots on the undersides of the leaves.
ALBs will be active through the warmer months in our region (September – May), so now is a great time to treat them.
As for scale, a dousing with soapy water will discourage these pests, however, a natural oil spray will give good control (spray oils when the weather is cool or late in the afternoon).
Some gardeners report good results from spraying fish emulsion fertiliser to the underside of the leaves.
For new plantings, look for Encore azaleas, in particular “Autumn Royalty” and “Autumn Twist”, as they have been touted as “lace bug resistant”.
JANE was wondering why her daylilsies weren’t flowering as well as they did a few years ago.
There’s usually a couple of reasons why daylilies won’t flower well.
The first is that they need an absolutely full sun aspect to produce their best blooms.
If the plants are in some shade for part of the day (nearby trees and shrubs may have grown taller over the years), they will not flower well.
In addition, as a daylily clump grows larger, the individual plants compete for space, light, nutrients and water.
This will almost certainly reduce their ability to produce maximum blooms.
To keep them at their peak, lift and divide in autumn or straight after winter.
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