Lemon trees produce delicious fruit, but that's only one of their many charms. Their lovely shape and dark green foliage makes them a beautiful addition to the landscape, and a few weeks out of the year, the blossoms fill the air with a sweet, citrusy fragrance. Unfortunately, of all the citrus trees, lemon trees are the most susceptible to cold. As a result, they can only grow in the warmest parts of the country and are especially prevalent in Florida, the Gulf Coast states, Arizona and Southern California.
Give the lemon trees a high-quality commercial fertilizer formulated especially for citrus during the growing season. Lemon trees need not only potassium, phosphorus and nitrogen, but micronutrients such as zinc, copper and magnesium. Because the amount depends on the size and age of the tree, it's important to follow the manufacturer's directions closely.
Water lemon trees deeply about once a week. It's good to let the soil dry out between watering, but keep a close eye on the soil around the tree, because allowing the soil to be completely dry longer than a day at a time can cause loss of leaves.
Prune lemon trees in midwinter. Remove any dead or damaged branches and remove low-hanging branches. Once you've done that, prune the remaining branches to keep the tree from becoming too tall, and remove branches that distort the shape of the tree.
Protect the lemon tree from possible freezing weather during the winter months. For young trees, protect the roots with a mound of leaves, mulch or soil built up to about 16 inches. If the trees aren't too large, they can be draped with a tree blanket, but don't leave the blanket on for more than a few days at a time because they need sunlight during the day.
Watch for yellowing of new leaves, which may indicate a lack of iron, which in severe cases, can result in shriveled or stunted leaves. If you suspect an iron deficiency, put an iron tablet in the soil near the tree.