Winter grub for your citrus tree we recommend using winter citrus feed during the colder months to ensure your citrus trees grow and maintain a strong crop of fruit and protect foliage buy winter citrus feed today from tree2mydoor uk using winter citrus feed is important during winter months to help maintain steady growth during colder and darker days winter citrus feed will help to prevent premature leaf fall and leaf discolouration our citrus feed is a nitrogen based fertiliser