|I have a star jasmine and some of the leave are yellow. Why?|
|If the yellowing leaves are the oldest (towards the center and on the lower stems), it is a natural shedding process. Evergreens such as jasmine drop their oldest leaves as they produce healthy new leaves. If the new leaves are yellowing, the plant might need to be fed or it could need more water. Or, there could be a population of insects such as aphids sucking the juices from the tissues of the plant. Inspect the leaves for these little critters and use Insecticidal Soap if you discover any.
Best wishes with your jasmine!