What does it mean when vinca leaves turn yellow?

Vincas with yellowing leaves are often reacting to a lack of iron, which is a common problem in alkaline soil. A lack of nitrogen in the soil can also cause yellowing leaves. Use of a fertilizer containing nitrogen, iron and sulfur helps to replace the nutrients while balancing the pH.Click to see full answer. Then, how often should I water vincas?Annual vinca is drought tolerant but does best if you water the plants whenever the top inch or so of the soil feels dry to the touch. Take care not to overwater this plant; it’s easily susceptible to root rot.Also, what causes yellow leaves on annuals? Abnormal yellowing of leaf tissue is called chlorosis. Leaves lack the essential green pigment chlorophyll. Possible causes include poor drainage, damaged roots, compacted roots, high soil pH, and nutrient deficiencies in the plant according to James Schuster University of Illinois Extension horticulture educator. Considering this, why are my vinca plants dying? Vincas, or periwinkles, can be infected with a fungal disease called aerial phytophthora. The disease spreads when the fungal spores in the soil are splashed on the plants when you water or when it rains. If rains or overwatering continues, the fungus can spread to the base of the plant and it can die.How do you care for vinca vines? Use & Care To control its height and spread, trim vinca back in early fall and cut back any unwanted vines as needed. Unless planted in a very hot part of the yard or in a dry climate, vinca will do well with little water. Vinca does not require fertilizer.