When life gives you lemons....
Citrus have always been popular. They are great tasting, vitamin rich, can be picked progressively over quite a long time and are relatively easy to grow. Early mandarins begin to ripen from early June with oranges, grapefruit and lemons holding on until January. This winter - early spring fruiting makes citrus so valuable when other fruit is more expensive. They are also very attractive trees with their glossy green leaves, fragrant blossom in spring and coloured fruit in winter.
Where to Plant
Citrus will grow in warm or mild climate zones. Providing frosts are not severe they will tolerate cool conditions. They will thrive in hot inland conditions providing they have water. They require a sunny position protected from cold winds. Citrus prefer a sandy or loam soil. They will tolerate clay soils providing they are planted on a raised area with lots of compost mixed into the soil.
How to plant
Refer to our blog What Makes a Good Soil
When to plant
Citrus trees are available most of the year and can be planted anytime provided they are watered regularly in summer. The best selection is available in autumn, which is the best time to plant.
After care
What do I feed my citrus tree?
Citrus are big feeders. A moderately sized mature tree requires at least 500g of Tui Citrus Food, ican Fruit Food, or Novatec each year (organic gardeners should use Tui Organic Fertiliser). Two thirds of this should be applied in late winter and one third in January. Pelletised Sheep Manure is a useful alternative. Do not cultivate under citrus trees as their feeding roots are relatively close to the surface.
How often do I need to water my citrus?
Citrus must be watered regularly through spring and summer. Irregular watering can cause fruit drop and fruit splitting, not to mention reduced yield and dry fruit.
Why should I mulch my citrus tree?
A layer of mulch spread over the surface under citrus trees will conserve moisture and improve performance. Take care however, to keep mulch away from the base of the tree trunk to avoid collar rot.
Pests and Diseases
Citrus trees can be attacked by white fly, scale insects, aphids, thrips, mealy bug and mites. The honeydew excreted by these pests then causes black sooty mould to build up on leaves and stems. Grosafe Enspray 99 oil applied every three months normally maintains satisfactory control. Increase the frequency if there is a build-up of insects. Verrucosis, a fungal disease which sometimes attacks lemons causing rough fruit, is controlled by spraying with Grosafe Free Flo Copper.
Whitefly can reproduce very quickly (they reproduce faster as temperatures rise in summer) so it is vital that you begin treatment at the first sign of them. Combine Enspray oil and Yates Mavrik and spray thoroughly, focussing on covering the underside of the leaves where they lay their eggs. Repeat after 10-14 days and a third time 10-14 days after that and ensure each time that you get complete coverage of the tree leaves. Especially the undersides. If you don't break the lifecycle, you won't get rid of the whiteflies.
If ants are all over your citrus tree, the ants themselves aren't a problem you need to treat but you can be sure that there is another type of insect on your citrus tree. Ants eat the honeydew produced by aphids, scale insects, whitefly etc so they will protect them, essentially 'farming' them! Get rid of the problem insects and the ants will go elsewhere to find food.
Do I need to prune my citrus tree?
Citrus tend to be self-shaping and so need little pruning in that regard. Most varieties can become quite dense and benefit from some thinning out. The benefit of thinning out is to maintain good airflow and light through the tree. Good airflow helps to minimise fungal diseases and pest infection as the centre is no longer sheltered and warm inside. Lemon trees can sometimes require pruning back to make them more compact and easier to manage. An old wives tale for how much to thin out a citrus tree was that 'a bird should be able to fly through it'. You don't have to test that theory but it gives you an indication of how open it should ideally be.
Make sure that any shoots that emerge below the graft are removed. These are easily identified as they have different foliage.
Citrus will fruit on 1 year old wood and/or on new seasons growth.
Making your selection
Lemons
What lemon variety should I choose?
Meyer variety is most popular because of it’s reliable high yield over an eight month picking period. The fruit is of medium size and sweeter than other varieties.
Yen Ben is an improved selection of Lisbon for those wanting a ‘real’ lemon for cooking. It has the best acidity and flavour.
Genoa is a variety which crops more heavily in summer when other varieties are very light.
Lemonade is a very sweet lemon that tastes like delicious lemonade and deserves its increasing popularity. Ripens during spring, but some ripe fruit can be found most of the year.
Grapefruit
What Grapefruit variety should I choose?
Golden Special, is the traditional grapefruit with pale orange skin and a strong grapefruit taste. Excellent for those who like a strong marmalade. Ripens July—Oct.
Wheeny is a larger sweeter variety ripening Oct—Dec and is inclined to biennial cropping. This means it has a very heavy crop one year and a light crop the following year.
Limes
Limes have become very popular in recent years, largely because of the interest in cooking created by the many cuisine programmes on TV, and in magazines.
Limes need protection from frost until established. They will not tolerate heavy frosts.
Most popular is the Tahitian Lime or selections such as Bearss Lime.
Kaffir Limes—mainly grown for the leaves, an essential ingredient in Asian cuisine.
Oranges
NZ navel oranges are rated very highly compared to imported oranges for flavour.
Which is the best orange variety to grow?
Carters or Washington navel oranges are reliable in all but the coldest climates of NZ. They ripen from Oct—Dec in most areas.
Lue Gim Gong is a Valencia type ripening from Oct—March
Mandarins
Very popular with families because they are great in school lunch boxes due to the easy peel nature of most varieties.
Which variety of Mandarin is best for me?
Silverhill or Miho are Satsuma types, ripening July and are easy peel.
Aoshima is another easy peel, ripening September-October.
Clementine has good flavour, is a high yielding reliable cropper ripening August—October but is not an easy peel.
Encore is a good late season variety ripening Nov-Dec.
Afourer is good for a long season harvest.
Tangelos
These are a very reliable cross between grapefruit and oranges, ripening Oct– Jan.
For full details on growing citrus including soil preparation, recommended varieties, feeding, pest and disease prevention and control become a subscriber to Pro Advice