Raspberry plants are not suitable for full sun. However, their natural distribution areas provide information about the requirements of the berry bushes. Some shade supports healthy growth and improves the harvest of your raspberries.
Natural Occurrence
Raspberries are considered undemanding plants that spread uncontrollably in the garden due to the lack of pruning measures. They are among the pioneer plants that prefer to grow in forests. The shrubs colonize bare areas and are therefore among the first plants to thrive in newly formed forest clearings or at the edges of forests. Rubus idaeus is widespread in the temperate to boreal climate zones of Europe. In the Mediterranean zone, the species is increasingly disappearing the further south it goes. Here their range is limited to the high altitudes in the mountains. This occurrence gives you valuable information about the site conditions, which you should consider when planting raspberries in the garden. Ideal growing places are:
- West side of a walnut tree ensuring shady conditions until midday
- Dry stone walls protecting from the midday sun
- North wall of a garden shed in the open space
Sun exposure problems
Some gardeners plant their raspberries in full sun. The harvest is only guaranteed if the water balance does not get out of balance during the hot summer months. Such locations are not ideal, because berry bushes suffer from increasing summer heat and prolonged drought as part of climate change. To protect against excessive evaporation, the stomata of the leaves are closed so that the metabolism slows down. The fruits that have already formed are exposed to the sun without protection. Sunburns on the leaves and fruit damage are the result. When the air temperature rises above 30 degrees, the first signs of raspberry degeneration appear. If the temperature in the fruit tissue rises above 40 degrees for more than two hours, irreversible damage follows. If the air temperature is otherwise above 40 degrees, the tissue of the berries slowly turns milky white.
Tip: Train your bush berries into a bush. Here the delicious fruits hang inside the plant and are better protected from too much sunlight.
prevent fruit damage
The damage is most severe when the previously shaded berries are suddenly exposed to the blazing sun. Due to lack of water, the cover of leaves collapses. In the fruit, not only does the tissue temperature increase, but also the respiration rate. Clumping and the death of proteins and enzymes occur, resulting in tissue breakdown. Climate change and increasing extreme conditions are also increasingly influencing the choice of location. To prevent fruit damage, you should pay attention to these site conditions:
- Raspberries need high humidity
- attach great importance to cool summer temperatures
- pay attention to a balanced light ratio
- ideal locations offer morning and evening sun
- sunscreen is recommended during lunchtime
Tip: In the case of raspberry plants in sunny locations, thinning out should only take place after the harvest so that the fruits are better shaded during ripening.
Varietal-dependent site selection
The location where your raspberries feel particularly at home depends on the variety you choose. Most of the cultivated forms prefer a semi-shady location. Still, few strains are hardy enough to tolerate full sun all day. Only the original species can also be planted in the light shade. Although the shrub also thrives in low-light conditions, planting in full shade is not recommended. Here the raspberry plant invests more energy in leaf development, so fewer flowers are formed and the harvest is very weak. These are recommended breeds for different locations:
- Sun: 'Saxa Record'
- Penumbra: 'Aroma Queen', 'Pokusa', 'Black Jewel', 'Golden Queen'
- Shadow: wild raspberry