Causes of Leaf Folding in Clivia and Methods for Controlling Edible Fungus Diseases and Pests

Leaf folding in Clivia is a normal physiological trait in the newer-generation Que Lan, Heng Lan, and old Changchun Lan cultivars such as "Ranchang." In other words, all of these cultivars, or any offspring carrying their genetic material, possess this trait. According to current aesthetic standards, severe leaf folding greatly diminishes the ornamental value of Clivia and is considered an undesirable leaf condition.

So then, when leaf folding also appears in other cultivars besides those mentioned above, what causes it? Experience shows that improper fertilization is a main cause. Heavy application of base fertilizer, side-dressing, and solid fertilizer, although long-lasting in effect, ferments and releases its nutrients all at once, far exceeding the amount the plant requires. Because this period lasts a relatively long time, it creates a prolonged excess of nutrients, putting the roots into an abnormal state of absorption and leading to deformed leaf growth. From observing folded leaves, a regular pattern can be seen: first, folded leaves are never longer than normal leaves; they are all shorter than normally grown leaves, and thick and hard. Second, if a folded leaf is spread out, its width is generally greater than that of a normally grown leaf.

From the above analysis, the conclusion can be drawn that excessive fertilization is an important cause of leaf folding. After discovering folded leaves on a plant, measures should be taken promptly: replace the soil with fresh humus soil and suspend fertilizing until new flat, smooth leaves grow out.