Certified Professional Horticulturist (CPH) Practice Exam

Dividing is the recommended technique for thinning out overcrowded plants. This method involves carefully separating the root systems of existing plants to create smaller, individual plants. By doing so, it not only alleviates overcrowding, allowing remaining plants to access more nutrients, light, and water, but it also promotes healthier growth and can rejuvenate the plants.

This technique is particularly effective for perennial plants and can contribute to the overall longevity and health of garden beds. Dividing can also create new plants, which allows for expansion of your garden or sharing with others.

While transplanting, pruning, and sowing have their own benefits in various contexts, they do not specifically address the issue of overcrowded plants in the same direct manner that dividing does. Transplanting could help by moving some plants away from each other, but it does not necessarily promote immediate benefits for the plants left behind as effectively as dividing would. Pruning generally involves cutting back foliage or branches to shape or reduce size, which would not address the root congestion. Sowing pertains to planting seeds and does not apply to existing overcrowded plants.