Most lemon trees, especially standard varieties found in home gardens, possess thorns. This feature is a natural characteristic of plants within the Citrus genus. While many commercial orchards select for less thorny cultivars, these sharp projections are typical for most lemon trees. Understanding the reasons for these thorns and how they vary can help home growers manage their trees effectively.
The Biological Function of Thorns
The sharp thorns on lemon trees are specialized, modified stems that develop at the nodes of the branches. These structures evolved as a passive defense mechanism against herbivores. In the wild, thorns discourage browsing animals, such as deer or smaller mammals, from consuming the tree’s tender foliage and young bark.
This defense is particularly important during the tree’s juvenile stage when it is most vulnerable. Thorns help protect the growing tips, ensuring the young tree can establish a mature root system and canopy. As the tree ages and its bark toughens, the production of new thorns often decreases, though this varies by cultivar.
Thorn Presence Among Common Lemon Cultivars
The degree of thorniness depends heavily on the specific cultivar chosen. Traditional and vigorous varieties, such as the Lisbon lemon, are known for being quite thorny, bearing large, sharp spikes along their twigs and branches.
The popular Eureka lemon typically has fewer thorns than the Lisbon, sometimes appearing nearly thornless on mature growth. By contrast, the Meyer lemon, a hybrid cross between a true lemon and a mandarin or orange, is the least thorny option. Meyer lemons usually have only small, blunt thorns or are completely thornless, which simplifies pruning and harvesting.
Even in less-thorny cultivars, the newest, fastest-growing wood often features the sharpest thorns. These include vertical shoots, often called “suckers,” which should be removed. Furthermore, if the tree is grafted, any growth originating from the rootstock below the graft union will likely display highly thorny characteristics.
Safe Handling and Management of Thorny Branches
Working with lemon trees requires safety precautions to avoid painful punctures and scratches. Gardeners should always wear thick, heavy-duty gloves, such as leather or reinforced synthetic material, when pruning or harvesting fruit. Wearing long sleeves and eye protection is also recommended, especially when reaching deep into the canopy.
Removing thorny branches will not harm the overall health of the tree. The most aggressive thorns often appear on water sprouts and suckers, which are vertical shoots that grow quickly and drain energy from fruit production. These highly thorny growths should be cut back cleanly to their point of origin to improve tree shape and safety.
Pruning for safety can be done at any time of year. Focus on branches that hang low or protrude into walkways and may pose a hazard. When removing larger, thorny branches, use clean, sharp pruning shears to make precise cuts that heal quickly. This selective pruning reduces the risk of injury while maintaining the tree’s energy for developing productive, fruit-bearing wood.