Certified Professional Horticulturist (CPH) Practice Exam

If your customer's potted plant has brown, crisp petals, what could be causing it?

1. Lack of primary nutrients

2. The plant is rootbound

3. Soluble salts

4. Lack of a porous container

The correct answer is: The plant is rootbound

The condition of having brown, crisp petals on a potted plant is often indicative of water stress, which can be exacerbated when a plant is rootbound. When a plant becomes rootbound, it means that the roots have grown to fill the pot and may be circling around the edges, restricting access to water and nutrients. This can lead to issues such as poor water retention and, consequently, dehydration. As the plant struggles to obtain adequate moisture, the petals can become desiccated and turn brown and crispy. While the other factors listed—such as lack of primary nutrients, high soluble salts, or inadequate container drainage—can also cause stress indicators in plants, rootbound conditions are a direct and specific cause that correlates with visible symptoms like brown, crispy petals. Ensuring that plants are in appropriately sized containers allows for ample root space, promoting healthy growth and hydration, thus preventing the symptoms associated with rootbound plants.