1) According to the temperature of this moment. I have read that it can snow until April. The ideal time to prune the mulberry tree is before the spring vegetative growth but avoid the intense frost of the coldest months.
2) The mulberry tree is a plant exuberant, most of the bud is able to bear fruit. Therefore, you can operate without much thoughts. Since, even in the event of drastic interventions, specimens don't fail to recover quickly.
- Pruning should be carried out by removing the branches damaged by the weather, dried, dressed, thinned or weakened. You also remove the branches that overlap between them, in such a way as to give more air and sun inside the foliage, for the maturation of the fruits even more inside.
- The branches of greater diameter must be trimmed to a third of their length, but, if necessary, it can also halve. In doing so we must always remember that the more buds are left on the mulberry, and the more the fruits are small, so if you want less blackberries, but full and juicy, you can perform pruning more pronounced.
- it is always general rule that you should not remove more than 30% of the total leaf area of the mulberry tree, to avoid imbalances in energy to the plant.
The pruning will always be in this period, performed in the same way.
And finally, an interesting advice: from the pruned branches can be removed mulberry bark, and set aside to ligatures in the garden (for example, those tomatoes and zucchini). This method 'ecological' avoids the use of synthetic strings!