Q: What causes my plants to have unhealthy leaves and how I can rectify the problem? These are photos of my rose (above) and hibiscus (below) plants. Also, how can I keep bugs off my plants? – Mary John-A: Both your plants need fertiliser. They appear to be deficient in magnesium and possibly also in potassium. Your hydrangea could additionally be lacking phosphorus.If possible, change the soils of the rose and hibiscus plants and add a fertiliser that includes phosphorus, potassium and magnesium. Follow instructions on the fertiliser package and do not over-fertilise. Some people use Epsom salts, which contain magnesium sulfate, as a source of magnesium.To control pests, you can mix neem oil with water in a 1:100 ratio and spray onto the plants.-Find out more in our Ready, Set, Grow! column in Star 2 – The Star [link in bio!]-If you have any gardening questions, send your queries to http://questions.eatsshootsandroots.com-* All questions are answered by Dr Christopher Teh, soil biologist and senior lecturer at Universiti Putra Malaysia #eatsshootsandroots #DearPlantDoctor #ReadySetGrowESR #TheStar #garden