CITRUS CULTURE

First plantings in the garden usually include at least one citrus plant - usually a lemon. Citrus overall embraces an interesting and attractive range of plants from more ornamental dwarf types to the larger and more commercially productive varieties. Unfortunately, because they appear non-complaining, citrus is usually left to look after itself; however, they do require some care. The following notes are a guide to situation, feeding, caring and ensuring the health of these wonderful plants.

SITE

A position protected from winds and heavy frost in full sun is ideal. Without as much sun, they will not set as much fruit but for the home gardener this may still be sufficient.

SOIL

A deep, friable slightly acidic loam soil type is best for the citrus. They will grow in light or heavier soils provided some soil preparation is done. Light soils will require some additional WATERWISE crystals and a mushroom or cow & compost mix to help retain moisture and add nutrient to the soil. Heavy soils may require mushroom compost and organic matter to aerate, as well as GYPSUM CLAY BREAKERto open soil and ensure sufficient drainage. Good drainage is essential for citrus.

PLANTING

Make sure the root-zone is moist before planting and then thoroughly water in after placing in position. Be careful to keep the tree level with the surrounding soil. Soil build-up around the trunk can cause collar rot. If you have clay soil do not dig into this. Raise the bed or plant the tree as above the subsoil clay level if possible. By digging into it a pool can be formed which will collect water below the surface and kill the tree.

WATERING

Citrus are not deep-rooted trees and thus require watering regularly.

Mostly their roots will be 1.2m to 1.5m below the surface. Care must be taken to ensure they have adequate watering during the hot summer months. In addition, be sure not to over water either.

MULCHING

Mulching in spring can help conserve moisture around citrus trees in the hot summer months. A combination of mushroom compost, cow compost and WATERWISE water crystals or PEATMOSS will provide excellent moisture holding capacity. Do not build up mulches to closely round trunk. It is advisable to remove the previous year’s mulch before putting a new one down. Do not dig around citrus trees as their feeding roots are close to the surface and they resent disturbance.

FEEDING

Citrus should be fed with THRIVE GRANULAR CITRUS food in early September and again in early March. They require a large amount of nitrogen, some of which can be provided by digging in a little cow manure or mushroom compost in early spring.

PRUNING

Pruning is really only necessary to remove dead wood and to cut out branches that are rubbing against each other. There is some advantage in training young trees to produce evenly spaced branches to allow light penetration into the centre of the tree. Citrus that have become too tall may be pruned back severely, make sure you cover the wounds with a tree wound dressing such as STERIPRUNE. It is advisable to ‘skirt’ trees. This means removing all shoots to a height of at least 45cm to avoid disease problems, which may occur if branches are able to touch the ground. Remember to remove all shoots that come from below the graft. These shoots may occasionally arise from under the stock and if not removed will grow more strongly then the graft and eventually kill it. Thus, a tree that started as an orange may end up producing lemons, which is the type of under-stock.

PESTS

Follow directions on the chemical packaging precisely. Remember to pay particular attention to the time from when you spray until when you can safely eat the fruit.

BORERS - may cause die back of limbs that are badly affected. Severely damaged limbs should be completely removed. Pour MALATHON or CONFIDOR concentrate into the holes to kill the insect and spray STERIPRUNEover the damaged bark to stop wood-rotting fungus disease.

BRONZE ORANGE BUG - these insects suck the sap from new shoots. Control the problem with FOLIMAT, CONFIDORor MALATHONas recommended.

CATERPILLARS - several types of these pests attack citrus. Spray with MAVRIK, success, DIPEL or pyrethrum to control.

FRUIT FLY - these puncture the fruit causing it to discolour and become infected with larvae. Spray with NATRASOAP or lebaycid watching timing of spray to final harvest of fruit.

SCALE - various types of scale affect citrus trees. WHITE OIL, PESTOIL or SCALE GUN should get rid of these. Bad infestations may need spraying twice two weeks apart.

DISEASES

Follow the directions on the chemicals precisely. Remember to pay close attention to the time from when you spray until when you can safely eat the fruit.

BLACK SPOT - this fungus causes slightly sunken brown or black spots on the fruit. Common on Valencia oranges grown in humid coastal areas. Spray with TRIFORINE, ZINEB, COPPER OXYCHLORIDE or MANCOZEB plus.

COLLAR ROT - the bark splits and becomes soggy near the base and gum may be exuded (this is caused by a fungus). Clean away the damaged bark and spray with ANTI-ROT. Seal the wound with a dressing such as STERIPRUNE.

MELANOSE - this fungus disease causes a brown stain or clusters of tiny brown spots on the fruit, leaves and stem. It may accompany die back of twigs.

SOOTY MOULD - this is a symptom of scale or aphid attack. It grows on the honeydew excreted by these pests. Spraying with COPPER OXYCHLORIDE will kill this problem but the pests causing it must also be controlled. FOLIMAT and clear white oil combined may be useful.