Yellow Leaves on My Angel Wing Begonia

Angel wing begonia is a long-blooming plant that thrives in partial shade. The flowers are pink or red and the plant is tall for a begonia at 12 to 15 inches in height. The flowering begins in May and may persist until October. Angel wing begonia is an ideal house plant; it can also be grown outdoors in planter boxes or flower beds. The shape of its leaves are the source of the name, as they taper into graceful points. Begonias in the landscape may experience several cultivation problems.

Poor Rooting

• Angel wing begonia is often propagated by cutting. The cuttings need plenty of time to grow a broad root system before they are transplanted. In the interest of commerce this is often not the case, and your begonia may be an unintended victim of early sale. Cuttings need less water while rooting and a soil-less potting mix. If the cutting was moved into a potting mix and watered too early, the leaves will yellow and fall off.

Leaf Spot and Other Fungal Diseases

• Leaf spot is one of many fungal diseases. Fungus is transferred via spores which can be carried on the wind or in water droplets. As soon as they find a moist, warm location they bloom and eventually fruit. Leaf spot can make holes in leaves, discolor the edges, create a mosaic effect or simply turn the foliage yellow. You can apply a fungicide but a better control method is cultural. Repot the begonia in a soil mixture with half peat that will minimize the amount of moisture held in soil. Begonias that are grown indoors can be placed in a room with a fan to minimize humidity. Never water begonias from the top; place a long watering spout at the base and water the roots only.

Shock and Environment

• Most plants will experience shock when they are moved, and the angel wing begonia is no exception. Shock may cause the plant leaves to yellow. The shock can be from transplant or from moving the plant into another location where temperature, humidity and lighting are different. The plant should not be placed in a window in full sun as this can cause it to discolor. The begonia requires warmth, which means the indoor begonia should not be near an air conditioner. The outdoor plant should be treated as an annual in cold climates or moved indoors to avoid yellowing leaves.

Poor Drainage

• Angel wing begonias appreciate evenly moist soil. When the plants are potted they need to have good drainage; roots sitting in water invites rot. The same is true of plants in the ground. Heavy clay soil will not drain adequately and the plant will become saturated, which can lead to leaf discoloration as the plant shows signs of illness. Of course, the leaves can discolor when there is not enough irrigation, but this is usually accompanied by shriveling and dry edges.

Mealybugs

• These armored tiny insects are sucking pests. They attach their mouth parts to tender stems and new growth and suck out the precious sap. This can cause the plant to lose its health as the sap contains the carbohydrates or plant sugars the begonia needs for continuous growth. Over time a heavy infestation of mealybugs will diminish the plant’s vigor and can cause the leaves to discolor and drop. Loss of leaves further lessens the begonia’s energy as it can no longer process the sun’s energy in photosynthesis.