Citrus sinensis

This evergreen citrus grows to around 5m tall and 7m wide.

Leaves are mid-green and mature to quite leathery to touch. Star-shaped single white, highly scented flowers bloom in spring, followed by spherical bright orange edible fruit which mature by winter.

Prefers full sun and very well-drained soil is essential. Citrus can get root rot easily in wet conditions over winter.

Always choose healthy, well-grown, plants and plant after autumn rains, when the soil is moist and warm allows trees to establish a good root system well before summer. Planting is often improved on clay soils by adding extra topsoil and forming raised beds. Incorporate coarse sand, bark, peat, compost or other organic material to improve soil structure. Before planting ensure the root ball is saturated and remove the planter bag or pot with minimal root disturbance. Trim any broken roots or branches and plant at the same level as in the container. Dig a hole twice the diameter of the root ball to plant in. Long term slow-release fertilisers may be added at this stage. As soil is placed in the prepared hole tread firmly to bring soil in close contact with the root-ball. Unless the soil is very wet, water thoroughly making sure that moisture penetrates to the depth of the root-ball. In windy positions, staking may be required. Use wide ties that hold securely without chafing. Tie firmly but allow room for the trunk to increase in girth without constriction. This allows the plant to move a little in the wind encouraging the development of a strong root system without the risk of chafing or root damage.

Apply mulch annually to help suppress weeds and conserve moisture. Oranges are the heaviest feeders in the citrus family so on soils with low fertility an application of nitrogen is beneficial. 1-2kg of blood and bone can be applied to each tree mixed with sulphate of potash at a ratio of 1:9 especially if there is a large amount of fruit. This protects against yellow foliage and little fruit set. A lack of phosphorus results in sour fruit and too much potassium results in more acidic fruit. Thin fruit on small plants after natural fruit drop has finished. This should be carried out in January, on young trees all fruit should be removed for the first two years so the plant can put all its energy into growth. Older plants need fruit thinning to one fruit per cluster, these should be well spaced down the branches. Small, young trees can have branches broken by fruit too heavy for them, plus too much fruit on young trees results in the fruit being of poor size, quality and taste and will sap the young tree of all its energy which will be detrimental to its growth.

Pruning should be done after fruiting has finished. Any dead, diseased or crossing branches should be removed. Trees should be kept pruned to allow plenty of air movement around the fruit. A vase-shaped tree should be aimed for by the removal of some of the central branches. This also helps keep the trees to a manageable size and increases light into the centre which helps more fruit set. Do not prune from the outside of the tree inwards as most of the following years fruit is carried on growth from the previous summer. Avoid pruning in September and October as new cuts may encourage borer to lay eggs in the new cuts.

Root rot can be a problem on wet sites. Scale insects, aphids and citrus whitefly can also be troublesome. Aphids then produce honeydew which in turn leads to sooty mould on lower leaves. This doesn’t affect the plant but does look unsightly. It can be easily wiped off with a damp cloth.

Orchard