In Italy and Spain, the sometimes very large bushes with the tireless splendor of flowers can be seen everywhere: even further north, for example in Ticino, many gardeners enjoy the magnificent shrubs in the garden. But even if you have discovered wonderful oleanders in the gardens in Bologna or on Lake Lugano: In Germany, planting out is not a good idea due to the very low frost hardiness.
Oleander thrives better outdoors in warmer regions
Oleander tolerates little frost
Oleander is only winter-proof down to about minus five degrees Celsius and can only tolerate these low frosts for a very short time. Deeper or even permanent minus degrees, as is common in many regions of Germany, are usually deadly for the Mediterranean shrub. The plant does not die immediately when its above-ground shoots freeze: In this case, simply cut the frozen bush back to just above the ground and it will sprout again. Deadly, however, is ground frost, in which the roots are affected and die off. Once the oleander roots have been frozen through, the plant can no longer be saved.
Planted oleander is more robust - but only with a plant pot!
For this reason, planted oleanders - whose roots are in the protective soil - are significantly more robust than tub oleanders, whose roots freeze faster through the planter. In mild winters, you can also hibernate the shrub by burying it (if possible in spring) in a suitable place in the garden. However, the plant pot must not be removed in order to be able to quickly dig up the oleander again when there is a threat of frost and put it in a safe winter quarters.
Properly wintering oleanders
Oleanders hibernate best in a frost-free, but cool and bright room at temperatures of around five degrees Celsius. For example, unheated greenhouses (€72.95) or conservatories, stairwells, attics or basements are ideal. Even if the location is dark, you can put the shrub there, but then the temperatures should not rise above two degrees Celsius. Do not forget to water the oleander about once a week, but you should stop fertilizing in late summer.
tips
As long as the temperatures are still mild, you can overwinter your oleander outside. In this case, it is best to pack it carefully with bubble wrap and/or gardening fleece and make sure that it is protected from wind and rain as much as possible.