Fruit trees and Cross-pollination
Fruit trees are a fabulous addition to any garden: not only do they add a home-grown element to your table, but they also promote a healthy ecosystem.
While growing fruit trees is a hobby even a novice gardener can succeed at, it’s important to know which trees you can plant individually that will fruit, and which require a mate for cross-pollination.
What is cross-pollination?
Cross-pollination is when the pollen of one plant fertilises the female parts of another plant, resulting in the formation of fruits or seeds. Pollination is especially important for fruit trees to crop successfully.
Many fruit trees are self-fertile and can pollinate themselves. Others, including certain varieties of apple, pear, plum, fig and cherry trees, are self-sterile and need a second tree for pollination. You’ll need to take this into consideration when planning to plant fruit trees: the size of your garden may determine whether you opt for self-pollinating trees, which are more conducive to smaller gardens, or those requiring a pollinating second tree.
Self-sterile versus self-fertile fruit trees
There’s no ‘one-size-fits-all’ scenario when it comes to fruit trees being either self-sterile or self-fertile: each type has varieties that can self-pollinate, and others requiring assistance to bear fruit.
Pear trees are a popular choice for the garden, both for their pretty blossoms and delicious fruit. They require little maintenance and thrive in regions with cold, wet winters and mild summers. Some varieties, such as the ‘Kieffer’, ‘Le Conte’ and ‘Packham’s Triumph’, can self-pollinate and will crop well in the lowveld. If you’re planting the ‘Early Bon Chretien’ pear tree, ensure that the ‘Forelle’ variety is planted nearby to act as a pollinator.
Who can resist the amazing blossoms of plum trees, and the sweet, juicy plums picked from your own garden? If you’re considering planting a plum tree, check which varieties are self-pollinating or need cross-pollinating, as space for two trees could be an issue.
Plum trees with the same colour fruit rarely cross-pollinate. Ideal cross-pollinating plum trees to plant are ‘Sapphire’ (red fruit) with ‘Sun Kiss’ (yellow fruit), ‘Harry Pickstone’ (red fruit) with ‘Purple Majesty’ (purple fruit), and ‘Sun Gold’ (yellow fruit) with ‘Laetitia’ (red fruit). Plums grow well in areas with cold winters and hot summers, such as the Boland region.
Mainly trouble-free and undemanding, fig trees are easy to grow in the ground or in containers, in climates with warm, dry summers and mild winters. The common fig tree can self-pollinate, and is the most common variety of fig tree that we find in gardens.
Figs that require cross-pollination have both male and female flowers. They’re pollinated by tiny wasps that collect and distribute the pollen.
Cherry trees are very susceptible to the elements and are only suitable to grow in certain areas. They don’t like the wind and hot sun, preferring cold but frost-free winters. Sour cherries are self-fertile, whereas sweet cherries are self-sterile so need a ‘partner’ tree.
Nothing tastes quite as good as a freshly picked, home- grown apple, and autumn/winter is the best time to plant them, while the soil still retains some warmth. The Western Cape is well suited for growing apple trees, with its long periods of low temperatures, although with so many varieties available, apple trees can grow successfully almost anywhere in the country.
Apple trees flower in mid-to-late spring, depending on the cultivar. Some are self-fertile and therefore ideal if space is at a premium, but most apples are self-sterile and need cross-pollination.
To cross-pollinate, apple trees must flower at a corresponding time. The alphabet method is used to label trees for cross- pollination, where ‘A’ corresponds to trees flowering earliest in the year. If one variety is labelled ‘A’, the compatible pollinator variety will also be labelled ‘A’, and so on. Groups ‘C’ and ‘D’ flower later and are the most popular cultivars.
These delicious fruiting trees are self-fertile so fruit well from a single tree. They’re pollinated by bees and other insects and can also be hand-pollinated to ensure a bountiful crop. Most cultivars thrive in colder regions as they need a cold winter to produce fruit, but some peach trees have been bred to grow in warmer areas.
All citrus trees are self-fertile and don’t require another cultivar for pollination. These health-giving, juicy fruits are available in a variety of different types, including oranges, lemons, naartjies, kumquats, grapefruits and minneolas. Citrus trees will grow in most frost-free areas of the country, but need some shelter from cold winds.
With their stunning blossoms, almond trees are a gorgeous addition to any garden. They aren’t self- pollinating so need a suitable pollinator with an overlapping blossom time. They are best suited to the Western Cape climate.
This nutritious fruit grows best in subtropical climates. The ‘Fuerte’ and ‘Hass’ varieties are self-fertile, although other cultivars need a compatible ‘partner’ in order to fruit.
Most types of fruit trees have both self-fertile and self-sterile cultivars. By selecting the right cultivar for your outdoor space and climate, you can soon enjoy home-grown apples in your pie, or garden-picked avos in your salad.