Cleaning houseplants regularly is important as plant foliage in the home collects dust just as the furniture does and, apart from making the plants look dirty, it impairs leaf functions and periodically should be removed by sponging or spraying. Large-leaved plants can be cleaned by wiping the leaves with a sponge, or soft cloth, dipped in soft water.
A little milk added to the water gives them a soft sheen, and any oil or grease on leaves can be removed by adding a few drops of vinegar to the water. A supporting hand should be put under the leaves as they are wiped to avoid any risk of damage and, whether they are cleaned with tepid water, soft soap and water, milk, skimmed milk, white oil emulsion or furniture polish, is a matter of choice. Oil has the advantage of acting as a pesticide against red spider, because it prevents the red spider moving around to feed. A weak mixture is advisable, not more than one dessert spoon to a gallon of water, otherwise the leaves may suffer as the oil will clog the pores a little and attract further dust. The plant must be kept in the shade until it is dry.
Fine leaved plants can be cleansed by close spraying with a mist sprayer but plants with hairy or downy leaves, cacti and succulents, can be more effectively freed from dust with a fine camel-hair brush.
Fallen foliage and dying flowers should be promptly removed, the surface soil lightly pricked over when necessary and moss growth removed.
House plants rarely suffer attack from insect pests, especially if the plants are given proper care and attention, examined about once a week and cleaned occasionally. However, sometimes one is unlucky enough to obtain a plant that is already infected, or to find that pests have invaded from outside. Infestation can usually be effectively controlled, if action is taken immediately pests are seen, usually by using lethal insecticides. It is, nevertheless, wise to remove an infested plant from the room to prevent any spread of infestation and also to carry out treatment. This should be done, either out of doors or in a well ventilated room or cellar, where insecticides can be used without harming household furniture or upsetting humans or pets.
House Plant Pests
The following descriptions are of pests that an owner of house plants may, on some occasions, be unlucky enough to find. Descriptions and methods of treatment are also included.
Ants are only likely to encroach from the garden if they have access to a fairly large area of dry sandy soil. They can cause much damage to roots and can be eradicated by dusting the soil with special powders.
Aphids attack all parts of the plant and seriously damage the tissues by sucking the juices from them. Colonies of these greenflycan sometimes be eradicated by hand, otherwise they must be sprayed with an insecticide, paying strict attention to the manufacturers instructions and applying it as a fine mist from a small syringe.
Mealy Bug is a slow moving insidious pest, which is covered with a mealy wax so that colonies of them look like small pieces of cotton wool. Under the protection of this covering they suck the sap from the leaves of the plant. The plants should be sponged with a spray-strength solution of a white oil emulsion, or the colonies dabbed with a swab of cotton wool on the end of a matchstick dipped in methylated spirit.
Red Spider feed in very large numbers on the undersides of the leaves of a wide range of plants, causing considerable debilitation and damage. The symptoms are yellow mottlings with a greyish cast on the upper surface of the leaf which in extreme cases will wither and drop off. They are barely visible to the unaided eye but an ordinary magnifying glass will show them up quite clearly. Spraying with liquid derris, persistently, at ten day intervals is an excellent non-poisonous remedy. They usually occur when conditions are warm and dry.
Scale Insects are strangely immobile insects that attach themselves like small brown limpets to the shoots and undersides of the leaves of plants. Syringing with an insecticide two or three times at ten day intervals is a good remedy but, for plants with large leaves, sponging with a spray-strength solution is probably a better method.
Thrips or blackflies are tiny, dark brown insects which attack both leaves and petals in large numbers causing much damage.
Insecticides or spraying with a soft-soap solution will control them.
White Flies are readily recognized as a rule as small white flies on the undersides of leaves and damage plants by sucking the sap. They are susceptible to insecticides and in plant rooms the growing of a few plants of African Marigolds has a deterrent effect.
