Dwarf lemon trees are a hybrid lemon tree cultivated for home growing. Their evergreen foliage, colourful fruit and delicious-smelling blossoms are attractive to gardeners and chefs alike. Also called Meyer lemon trees, dwarf lemon tree problems are few and all have simple solutions.
Bloom and Fruit Drop
While some bloom and fruit drop is to be expected on dwarf lemon trees, excessive dropping is an indication of inadequate watering. When the tree becomes too dry, the fruit drops off within a few days after heavy watering. The best remedy for this is to adopt a consistent watering schedule that provides adequate moisture for the tree. Dwarf lemon trees planted in the ground should be watered deeply at least once a week. Indoor and outdoor container trees will require watering at least twice a week.
If the foliage of the dwarf lemon tree turns yellow, it could be the result of excessive watering or inadequate fertiliser. When the trees are overwatered, the root tips begin to rot and do not take up the necessary nutrients. Dwarf lemon trees like deep, infrequent watering so that they always remain slightly dry. A moisture meter, an inexpensive tool that can be purchased at garden centres, will gauge the true moisture levels of the soil.
Yellow foliage can also indicate a lack of available nutrients in the soil. Proper application of fertiliser will correct this problem. Since dwarf lemon trees need heavy doses of nitrogen, fertiliser should contain more nitrogen than phosphorous and potassium. Specialised citrus fertilisers available at most garden centres can help take the guesswork out of choosing an appropriate fertiliser.
Similar to yellow foliage, leaf drop is a symptom of overwatering or insufficient watering. The same is true if the twigs of the plant die back. Maintaining a consistent watering schedule with the help of a moisture meter is the best remedy for these dwarf lemon tree problems.
Good Growth, No Fruit
Dwarf lemon trees that have vigorous growth and overall health but do not produce fruit may be affected by a root sucker below the graft line of the tree. Since dwarf lemon trees are grown through grafting, each tree will have a diagonal scar--the graft line--on the lower portion of the tree. When growth comes out below that line, it is called a sucker because the shoots of new growth suck the vitality from the top of the tree where fruiting occurs. To remedy this, prune the new shoot below the graft line as soon as it is discovered.
Insects and Pests
Occasionally dwarf lemon trees experience problems associated with insects and pests, including ants, scales, aphids and mites. Some insects like spiders, ladybugs and lacewings are beneficial, but the pests should be removed immediately by spraying the tree with a solution of mild dish soap and water, or horticultural oil. The most common symptoms of bug infestation are sticky leaves, small black or brown spots, or white speckled leaves.