When the trees flower, they need to be pollinated by other species. This is done by bees or by wind and takes place when the trees flower. The importance of cross-pollination differs between the areas and the local conditions you farm in. In the coastal areas it is more important to have more than one variety of mac-trees on your farm than in other areas. You want to have different varieties flowering at the same time. Now, trees will flower when there is a dry spell. You will have flowering in off-season and some varieties will flower 2-3 times a year. A Beaumont will flower at the same time as the A4 so they go together very well. A 791 will flower 3 times a year throughout the year.
In Mpumalanga it is easier to predict the flowering since the weather stays dry for long spells. There are also more bees available throughout the year than in the coastal regions. Therefore, it is more important to have more than one variety in the coastal areas.