My blackberry vine is turning yellow. Is that normal?
The Gardener’s Answer
Hello, Lillian in California: Blackberries are such a treat to have in the home garden. Yellow foliage on blackberries can be an indication of too much moisture, lack of iron (chlorosis), or other potential problems. Blackberries are subject to several different insect and disease issues. Like all other plants they are more susceptible to problems when they are stressed and not growing in ideal conditions. Blackberries thrive when they are planted in a space where they receive full sun. They require nutrient-rich, well-drained soil with a pH between 5.5 and 6.5. Severe mite infestation can cause yellow foliage but if the veins of the foliage are green and the rest of it is yellow, you may be dealing with a nutrient deficiency. I can’t give you a specific answer without a sample of your plant but you can take a sample to your county cooperative Extension service. The agriculture/horticulture agent(s) will be able to identify the problem and give you suggestions for control. You can also have your soil tested through the Extension service, which may not be a bad if you have not already done so. You can visit the Orange County Web site at http://ceorange.ucdavis.edu. If you are interested in reading a publication on growing blackberries in California you can visit http://cesonoma.ucdavis.edu/files/27140.pdf.