Lauren Addison of Salt Rock writes My star jasmines were flourishing but I lost at least six plants over a couple of months last year. The leaves that should be green turned a beautiful red before falling off or drying up. I thought it may have been because they were too dry in winter but the problem persisted last summer. I replaced the ones I had lost with healthy new plants but I see the new ones also have leaves that are turning red. I sprayed for ants and red spider, which I thought could be the problem, but to no avail. Any advice?
JJ replies Yes, leaves turning red is normally a sign of a lack of water and the soil could also be drying out too quickly. Plants from the nursery usually come in a bag with good quality potting soil. As the roots develop and grow past this potting soil, they often come into contact with sandy soil which causes them to dry out more quickly. If that happens during summer and the plants with underdeveloped root systems are exposed to excessive heat, you’ll see the negative effects sooner. Replace the soil, add compost and replant. When replanting, cut off about 20% of the plant to give the roots a bigger advantage. Feed with a fertiliser higher in nitrogen such as a 7:1:3 every two months.