The genus Streptocarpus has over 155 species. One of the most prevalent is common primrose. This streptocarpus plant features an African violet-like flower. This bloom has small flower petals with rich shades of purple, pink and red. It is compact and features hairy leaves on a stalk that ranges from 6 to 12 inches in height. The leaves of the streptocarpus may wilt and change colours for a variety of reasons if not cared for properly, and it is not unusual for streptocarpus leaves to turn yellow.
The soil for your streptocarpus plant is one of the many important factors affecting its health. If the flowers do not appear healthy, you should try a different soil composition. Use an African violet soil mixture in a shallow container. Combine 1 part of perlite mix with 1 part of vermiculite and 1.5 parts of peat moss to create the correct soil composition for your streptocarpus.
The fertiliser must also be the right type for your streptocarpus to keep its vibrant purple colour. Without proper nutrition, the plant will tend to wilt and the leaves will degenerate into a yellowish colour. For fertiliser, you should use either bone meal or an African violet fertiliser. Apply fertiliser twice a month. You can also use a phosphate fertiliser, but you will need to reduce the frequency of application to once a month.
Light and Temperature
Your streptocarpus can also turn yellow if the lighting and temperature conditions are not appropriate, and this will also cause wilting. The light should be medium and indirect. The plant should not be exposed to direct sunlight all day. Keeping them cool at night should not be a problem, but during the day, the streptocarpus should be kept between 12.8 and 23.9 degrees Celsius.
There are a variety of other possible causes for leaf yellowing. These include too much or too little water, overpruning or too little heat. If your leaves are wilting and turning yellow, you can try exposing them to more light to dry out the soil. Yellowing can also be caused by a mealybug infestation, and you will need to combat this problem with insecticide.