House plants are a popular way to bring a bit of nature indoors. They are also a way to grow plants for those who do not have time to work in a traditional garden, or for those who may not have the space to garden in any other way. House plants are protected from a host of pests and diseases because they are indoors, but they are not entirely immune to disease.
African violets are compact, flowering plants characterized by their thick, deep green and fuzzy leaves. Depending on the cultivar, African violets bloom in a range of colors including blue-violet, pink, and white. Blooms may appear in double or semi-double rows. According to the University of Rhode Island, these plants are particularly susceptible to petiole rot, a disease that appears as a rust colored spot where the leaf stalk touches the soil or the edge of the container. Prevent this disease by covering the rim of the pot with aluminum foil. African violets are also susceptible to Botrytis blight, a disease that causes small, watery spots on the leaf undersides. The spots can enlarge and cause the leaves to turn entirely brown or black, and the flower petals may also suffer. This disease is often caused by mites, so prevent it by controlling mites with an insecticide.
According to the Amaryllis Bulb Company, a bulb distributor, this plant is one of the simplest to bring to bloom of all the types of flowering bulbs. Amaryllis produces large blooms in various colors including shades of pink, red, and orange. Red blotch is a fungal disease that is commonly found in amaryllis. It causes elongated, sunken, red blotches to appear on the leaves and flower stalks. This disease is difficult to control, so prevention is the key. Use sterilized potting soil and destroy any infected bulbs or plants.
Most popular for its colorful foliage, coleus grows in many colors including copper, crimson, and several different shades of green. Coleus is particularly susceptible to a disease called downy mildew. The mildew can be simply rubbed from the leaves, or, in the event of a major infestation, the disease can be treated by spraying a fungicide on the plant. Coleus is also susceptible to oedema, a disease caused when the plant cannot use water as fast as it takes it in. Overwatering is the main cause of oedema. Put a halt to watering for a few days once oedema has been identified, and place the plant in a sunny, breezy spot to help it recover.