Certified Professional Horticulturist (CPH) Practice Exam

What is the major reason weeds are considered to be undesirable in the landscape?

1. They are not as pretty as other plants

2. They compete with other plants for water

3. They do not grow as well as other plants

4. They need specific growing requirements

The correct answer is: They compete with other plants for water

Weeds are primarily considered undesirable in the landscape because they compete with cultivated plants for essential resources such as water, nutrients, and light. This competition can hinder the growth and health of desirable plants, leading to reduced yields in gardens and landscapes. Weeds often have aggressive growth patterns and can quickly overshadow or outcompete more desirable species, which can disrupt the intended design and ecology of the landscape. While aesthetics may play a role in how weeds are perceived, their impact on resource competition is a fundamental reason for their classification as undesirable. Weeds' ability to thrive in a variety of conditions can make them particularly problematic, as they tend to adapt quickly and invade spaces where they can overpower other plants. Therefore, the correct understanding of their disadvantage largely hinges on their competitive nature.