Plums were introduced into South Africa in 1656. The trees require a low temperature in winter (winter chilling) to enter into a rest period (dormancy).
The minimum air temperature during this period should be between 2,5°C and 12,5°C for a period of 850 to 1 000 hours.
Plum trees prefer deep, well-drained soils, ranging from sandy loam to sandy clay loam, with an effective depth of at least 600mm.
The trees are more tolerant of heavy or waterlogged soil than most other stone fruit types. The soil should have a pH of between 5,5 and 6,5.
Take the following into account before establishing the trees: slope, plant density, orchard design, planting date and planting depth.
Plant density will depend on the properties of the selected rootstock and the training system to be used. Under normal circumstances, you should plant the trees between 1,5m and 2m apart within the row, and establish the rows 4m to 5m apart.
If the soil is ridged, plant the trees 2m apart in the row and with an inter-row spacing of 4,5m.
Your fertilisation programme should be based on the results of soil and leaf analyses. Fertilise newly planted trees in the first year after new leaves have appeared in spring.
Place the fertiliser at, and slightly beyond, the canopy edge of the tree, never against the tree. Repeat in the second year.
Pest and disease control
The most common pests of plum trees are banded fruit weevil, scale (red and pernicious), thrips, American bollworm, fruitfly and codling moth. You can control these biologically, culturally, physically or chemically.
Birds are useful predators of these pests, and chickens and guinea fowl can be used to reduce weevil numbers. If weevils are a particular problem, remove weeds from the rows and place sticky bands around the trunks of the trees to prevent the adult weevils from reaching the canopy.
Source: ‘Plums’. 2008.