Most gardeners have long understood that sea buckthorn is planted only in pairs, but this is not the whole list of paired crops.
The fact is that there are self-fertile plants that simply lack a neighbor pollinator responsible for cross-pollination for pollination.
These are not only trees, but also bushes.
For normal fruiting of a self-fertile species, the partner plant is planted no further than 6 meters.
It may be a plant of another variety, but its flowering and fruiting period should coincide with the self-fertile one.
This information should be clarified at the time of purchase of seedlings, otherwise you will not get a harvest from a single crop.
Apple tree. Even an apple tree needs a pollinator if it grows in the north-western regions. But closely related varieties (for example, Antonovka with Antonovka) should not be planted next to each other.
Neighbors and pears are needed, but there are not many such varieties. The problem is solved by planting two seedlings of different varieties, which contributes to cross-pollination.
Felt cherries should also grow in pairs with their relatives.
It happens that there are such trees among cherries and plums, but in most cases these are self-pollinating varieties.
But peaches and apricots grow and bear fruit without a pair.
First of all, this applies to gooseberries and currants. If, with proper care, the crops do not bear fruit or give a bad harvest, try to plant a neighbor of another variety to them.
It is also worth considering that sometimes the problem is solved by vaccination.