Evergreen, spreading shrub to small tree that produces lemon fruit in winter.
Flowers and foliage
Small, highly scented, white flowers are produced in summer, followed by rounded yellow lemons from June to November.
Unlike most citrus, lemons are tolerant of both sandy and clay soils. Select sheltered sites in full sun and with good drainage. The sunnier the position, the sweeter the fruit will be.
Preparation for planting
All citruses prefer well-drained fertile soil, so use gypsum to loosen heavier soils if required. Always choose healthy, well-grown plants and plant after autumn rains. Before planting, ensure the root ball is saturated and remove the planter pot with minimal root disturbance. Trim any broken roots and plant at the same level as in the container. Dig a hole twice the diameter of the root ball, press in and water once planted. Make sure plants are watered well until established if planting in a drier period. Plant with some slow-release citrus fertiliser and then every spring apply organic fertiliser (such as blood and bone) at a handful per square metre.
Apply mulch annually to improve soil health and moisture retention and suppress weeds. Citrus are heavy feeders, so feed every 6 weeks with citrus fertiliser through spring and summer. The first summer and autumn after planting are critical for young plants, so water thoroughly during dry periods. Plants in containers should also be watered regularly. If they don't get enough water, growth will be poor and fruit will either drop or be bitter tasting.
Citrus are heavy croppers, so in the first few years, it is recommended that all fruit is removed. This will ensure the tree puts its energy into growth. In subsequent years, early removal of approximately 1/3 of heavy crops is best. If fruit is left on the plant, the weight will damage the tree and the resulting fruit will be of poor quality. Removal of a portion of fruit will also guard against biannual cropping (production of fruit only once every two years). Most citruses are grafted and can occasionally produce shoots from below the graft. These should be removed as they may eventually take over the main plant.
Pruning is only required for shape and is best done after flowering. However, if large limbs are taken off, paint the cuts with pruning paste. This will discourage borer infestation. Citruses have shallow roots, so planting underneath the tree is not recommended (other than annuals, which also have shallow roots).
Ecological and biodiversity benefits
Pests and diseases
Citruses are susceptible to magnesium deficiency, shown by yellowing of the leaves. A magnesium deficiency can be remedied by applying Epsom Salts or Sequestron Plant Tonic. Aphids can also be troublesome, as they secrete honeydew which encourages unsightly sooty mould. This can be removed with a damp cloth.
Although lemons are fairly tough, they are more susceptible than other citruses to borer beetle and verrucosis scabs on the fruit.
Location at Auckland Botanic Gardens