How to Care for Citrus Topiary

General Care

Citrus are Mediterranean plants and to understand their requirements it is useful to think of the conditions they are accustomed to in that environment. They have hot dry summers and a year long exposure to high light levels, well drained soils and rain that falls mainly in winter.

Growing citrus in this country can be very satisfactory especially if you take care of the growing conditions.

Citrus prefer to be outside in the summer months where the light levels and air circulation is beneficial to the health of the plants. Make sure they are protected from damaging cold winds. In this country they are best suited to container growing.           

Winter Care

All citrus must be protected from the winter cold in this country. All citrus prefer a cool winter rest period. Lemons require a minimum winter temperature of 10 degrees centigrade and Calamondin Oranges require 13 degrees centigrade whilst others can withstand 7 degrees centigrade. Citrus require high light levels so it is sensible to locate them close to a window, preferably in a cool greenhouse or conservatory. However try and ensure that the temperature levels do not fluctuate too much as low temperatures can cause failure to flower or loss of leaves. Take care not to overwater in winter, water only when the top layer of compost has dried out, you are more likely to overwater rather than underwater during winter. In winter it is necessary to continue feeding your citrus plant but change to a balanced fertilizer, this helps prevent leaf drop and contributes to the general health of the plant during winter but does not encourage excessive growth. You can keep the air around your plant moist by putting gravel in the saucer underneath the pot and keeping this damp, do not let this water come above the level of the gravel as it may come into contact with the roots and cause them to rot. This moist gravel will also aid the blossom to set fruit 

Pruning

The main reason for pruning citrus trees is to maintain their shape and size and to increase the air flow within the tree. There are 2 types of pruning for citrus plants. Firstly any misplaced shoots or branches can be removed in February. At this time you can also shorten any branches necessary to keep the tree bushy. Secondly, during summer pinch out the ends of any vigorous shoots that are going to grow too tall for the shape of the tree.

If there is a lot of young fruit you will probably find that the tree will shed a certain percentage of this which is normal as the tree is protecting itself from overbearing. 

Watering

Although citrus enjoy a humid atmosphere, it is important to avoid overwatering. Water freely in a hot summer, ensuring the pot is not standing in water and during winter only apply water when the surface of the compost has dried out. Too much watering in winter can cause yellowing of leaves or loss of leaves. Yellowing of leaves can also be a symptom of dry roots so check the soil before you take action. 

Feeding

Citrus are heavy feeders. Use a fertilizer with a high nitrogen content from spring to late October when you can change to a balanced fertilizer for the winter. Continue to feed during winter. Try to apply fertilizers on a regular basis.

Potting On

The best time to pot on citrus is during early spring. When potting on citrus us a loam based compost such as John Innes No 2, preferably using the ericaceous variety if you have a hard water supply as citrus prefer a slightly acid growing medium. Additional grit added to the mix helps the drainage. Special citrus composts are also available. Only pot on to one size larger at a time. 

Temperature

Temperature control is important for citrus. Too much heat or excessive cold can cause the leaves to drop. Fluctuations in temperature are most damaging. However, no citrus will tolerate prolonged cold weather. Keep within the minimum temperatures. Hot and dry conditions can cause the leaves to become scorched, using gravel in a saucer under the pot helps to avoid this very drying atmosphere. 

Pests

Red spider mite, scale insects and woolly aphids can cause problems particularly when under glass. If only a mild infestation, try removing affected leaves. If heavily infected then you will need a recommended insecticide and follow the instructions carefully.