Certified Professional Horticulturist (CPH) Practice Exam

Using a knife to cut a root ball that is surrounded by a mass of roots prevents the formation of which type of roots?

1. Too many feeder roots

2. Root rot

3. Girdling roots

4. Tap roots

The correct answer is: Girdling roots

Using a knife to cut a root ball that is surrounded by a mass of roots is a practice that directly prevents the formation of girdling roots. Girdling roots occur when roots grow in a circular pattern around the root ball or along the surface of the soil, effectively encircling the trunk or other roots. This can restrict the plant’s growth and limit access to essential nutrients and water, as well as cause girdling which can eventually lead to plant stress or death. By cutting through the densely packed roots at the edges of the root ball, the practice encourages new growth by allowing the remaining roots to spread out into the surrounding soil instead of continuing to grow in a circle. This naturally promotes a healthier root system, enabling better nutrient uptake and overall plant health. The other options do not relate to the primary issue that cutting the root ball addresses. For example, while feeder roots are important for nutrient uptake, cutting does not lead to an excessive number of them; root rot is typically a result of over-watering or poor drainage rather than root ball manipulation, and tap roots are not adversely affected by cutting the surrounding roots since they serve a different function.