What does it mean when you are told to plant in threes?
Planting in odd numbered groups is done to provide a more natural, non-linear look to the landscape. Instead of rows plants are grouped in clusters. Three is the smallest group size that will give you a non-rectangular shape (triangle). Even in the most formal of gardens
you will find odd numbers of plants, with a center focal point and balanced plantings on each side. For most people the results of planting in odd numbers is most pleasing to the eye