EVERGREEN AZALEA PLANTING HINTS
The cultural requirements for these plants are very similar to those for rhododendrons, though they have finer roots and are even less able to penetrate heavy sticky soil types. We recommend that more attention should be given to the texture of the soil in which evergreen azaleas are planted. One should aim to have a fluffy, airy, humus filled soil, but one that is still able to hold moisture. Materials to provide such a mix are peat, rotted leaf mould, garden compost, rotted pea straw and granulated bark. We recommend not to use animal manures unless they have been outside for a season, are well leached and have all the soluble salts leached out of them.
Evergreen azaleas do not have high fertiliser requirements but the addition of fertiliser at the time of planting is important. The use of a slow release fertiliser such as Cross Hills Long-Life Fertiliser is the safest method. The two most common deficiencies that can occur are Iron deficiency and Magnesium deficiency. Please scroll through our garden products and add Long-Life Fertiliser to your shopping cart.
IRON DEFICIENCY Shows as a yellowing of the leaf with the veins remaining dark green. Iron Sulphate applied direct to the soil will correct this problem.
MAGNESIUM DEFICIENCY This symptom is very similar to Iron deficiency. It probably pays to treat for this deficiency at the same time using Magnesium Sulphate (Epsom Salts). Remember extra time spent in preparing the soil is rewarded later with healthier stronger plants which are less prone to disease and pests. In hotter areas of New Zealand you may find that some will suffer to some degree from sun scald, when planted in full sun. They are easy to shift, so some experimentation may be required.
PESTS The most common pest that attacks evergreen azaleas would be the leaf roller caterpillar. It is easy to pick up on your plants by its characteristic habit of curling the leaf tip under and hiding in the curled up tip. The most practical solution is spraying with a systemic insecticide such as Cross Hills Super Thrips Killer. Check after two or three days to ensure the caterpillars are dead. Please scroll down and add Super Thrips Killer to your shopping cart.
PRUNING Pruning early in the life of an azalea is the best time to ensure your plant will end up a good shape. The easiest way to achieve this is by pinching out the terminal buds during spring or early summer (after flowering). This will cause several buds to shoot out below the pruned point. Don’t pinch or prune too late in the season or you will lose next year’s flower buds.
The pruning of older plants is sometimes necessary to keep them the right shape or to rejuvenate them. If pruning to shape and the plant is still very leafy, pruning back just after flowering will allow the plant time to shoot and hopefully set flower buds for the following season. The pruning of old open bushes has to be done with greater care and probably spread over two years. Remove any dead wood and then prune back still leaving some leaves on the stems. This first prune back should encourage shooting from lower down on the bush.
It is important to apply a light dressing of fertiliser (and wash in) to pruned plants, to give them an extra boost.
LICHEN If your old evergreen azaleas, or deciduous azaleas, are covered in lichen the reason for this is most likely the condition of the soil they are growing in. It may be sour or waterlogged with virtually no goodness left in it. The plant will not look healthy and the growth will probably be stunted. Lichen can be removed but the overall growing conditions have to be improved e.g. soil, light and nutrients.
Lichen has to date, been difficult to remove. In the past we have sprayed our deciduous azaleas with copper oxychloride in July, with reasonable success. We now use Surrender a product developed to be plant friendly and at the same time giving excellent results in controlling Moss and Lichen, Liverwort and Algae on plastic tunnell houses, fences and that shady side of the house.
When deciduous azaleas are at their most dormant stage, mid winter, Surrender can be sprayed over them to control lichen. One spray should be sufficient. The dead lichen can be rubbed off after two or three weeks or left to rot off or be pushed off as the plant grows. You will know it has worked when the lichen has turned white in colour.
Although Moss & Lichen Killer has proven safe when in contact with most plant foliage, in the case of lichen on evergreen azaleas extra care should be exercised. Only the affected stems should be sprayed, if contact is made with leaves, lightly irrigate foliage after 30 minutes. It can be used on other plants affected with lichen. 1 litre can make up to 100 litres of mix depending on dilution required for job on hand. Please scroll through our garden products and add Moss & Lichen Killer to your shopping cart.