Causes of Yellow Leaves on Potted Flowers and Methods for Pest and Disease Prevention

Potted flowers are limited by growing conditions, and improper daily management can easily lead to yellowing leaves. In mild cases it affects normal growth; in severe cases the whole plant withers and dies. Therefore, during care you should always observe closely, judge correctly, figure out what is causing the yellow leaves, take corresponding measures, and correct the problem promptly.

Overwatering: when the potting soil stays wet and waterlogged for a long time, the roots suffocate and rot, and cannot normally absorb water and nutrients, causing yellow leaves or even leaf drop. If you find yellow leaves, stop watering immediately, loosen the potting soil, and place the plant in a ventilated, dry spot to speed up evaporation. Watering should follow the principle of watering when dry and keeping it moist, and watering thoroughly when you do water; never water in small dribs and drabs. In addition, never spray water on the flowers during the blooming period.

Lack of water: if the leaves droop from lack of water, spray water on the leaves immediately to speed up the plant's water absorption, then water the pot. At this point, be careful to water only a little, just enough to moisten the soil, and never water heavily.

Improper fertilizing: during the growing period of potted flowers, going a long time without fertilizing or applying too little fertilizer can cause yellow leaves; applying too much concentrated fertilizer burns the roots and affects water absorption, which likewise causes yellow leaves, so you can water more to dilute it and wash the fertilizer out of the soil. A lack of fertilizer can cause the potting soil to harden, with leaves turning yellow, thin and scrawny, and branches slender, yellow and tender; in that case, fertilize immediately.

High alkalinity: because potted flowers are watered over a long period, salt and alkali accumulate in the potting soil, and in severe cases this causes the leaves to turn yellow and drop. You should replace the soil with new soil or spray a ferrous sulfate solution on the leaves; you can also apply alum fertilizer water and fermented rice-washing water, both of which give good results, but never apply too much.

Dry air: some flowers grown in the north that like humid air, such as camellias and orchids (Cymbidium), often develop dry leaf tips, scorched leaf margins or scorch spots on the leaves, and curled, wrinkled edges turning brown when the air is too dry. This is especially severe in areas where coal fires or heating are used indoors in winter. At such times you should often spray and wash the branches and leaves with water close to room temperature to increase air humidity.

Big flowers in a small pot: when the flowers are large and the root system is extensive, they need more water and fertilizer, and a small pot cannot meet the plant's growth needs, so the old leaves become dry, yellow and lusterless, and the new leaves are yellow and thin. You should repot into a pot of appropriate size, and add 30% humus soil to the soil so the flowers grow normally.

Overly dense branches and leaves: luxuriant branch and leaf growth plus a long period without pruning leaves the inner branches and leaves short of light, causing leaves to turn yellow and drop. You should prune the inner branches more heavily to improve ventilation, and fertilize appropriately.

Insufficient light: for sun-loving flowers such as Chinese roses and pomegranate, if they are kept in a place with too little light for a long time, the plant gradually weakens, with thin, yellow leaves and no or few flowers. You should move it to a spot with ample light.