The Ginkgo biloba, or maidenhair tree, is a unique and resilient species known for its distinctive fan-shaped leaves and bright golden fall color. Highly tolerant of urban conditions, pests, and disease, the ginkgo requires thoughtful pruning to maintain its shape and structural integrity. This process, especially during the tree’s formative years, is strategic guidance. Understanding the proper techniques ensures the ginkgo develops into a strong, long-lived specimen.
Ideal Timing and Necessary Tools
The optimal time for pruning Ginkgo biloba is during its dormant season, spanning from late winter to early spring, just before the buds begin to swell. Pruning during this period minimizes stress because the majority of the tree’s energy reserves are stored in the roots. This timing also allows the tree to begin its natural healing process, known as compartmentalization, as soon as the spring growth cycle starts.
Pruning outside of the dormant season should be limited to the removal of dead or damaged wood. Heavy cuts made when the tree is actively growing can stress the tree and potentially lead to excessive sap loss.
To execute precise cuts and prevent the spread of pathogens, use sharp, well-maintained tools and wipe the blades with a disinfectant, such as rubbing alcohol, between trees.
- For smaller branches, use sterilized bypass hand pruners.
- For limbs up to about 1.5 inches in diameter, use long-handled loppers for adequate leverage.
- Branches exceeding two inches in diameter require a handsaw.
Structural Training for Young Ginkgos
Formative pruning is the single most impactful action you can take to establish a healthy, long-term structure for a young ginkgo tree, typically within its first seven years. The primary goal is to establish a strong central leader, which is the single, upward-growing stem that will direct the tree’s vertical growth. Ginkgos have a natural tendency to develop multiple competing vertical shoots, known as co-dominant leaders, which must be addressed early.
Select the most vigorous and straightest shoot to be the single central leader, then remove or significantly shorten all other competing vertical branches. This action directs the tree’s energy toward the chosen leader, ensuring a structurally sound trunk. You should also select permanent scaffold branches that have wide angles of attachment to the trunk, ideally greater than 45 degrees, as these attachments are much stronger than narrow, V-shaped crotches.
Branches that form narrow crotches should be removed because they are structurally weak and highly susceptible to splitting under the weight of snow or high winds. When training a young tree, it is important to adhere to the “one-third rule,” meaning you should never remove more than one-third of the total live canopy in a single pruning season. This conservative approach prevents shock and ensures the tree retains enough foliage for robust growth.
The lowest branches that will eventually interfere with pedestrian or vehicle clearance can be temporarily managed by shortening them rather than removing them completely. Retaining some lower branches for a few years helps the trunk grow in diameter and prevents the tree from becoming top-heavy. As the tree grows taller, these temporary branches can be slowly removed over several seasons to achieve the desired clearance height.
Maintenance Pruning for Established Trees
Once a ginkgo is established, pruning shifts from structural training to routine health and safety maintenance. While general work is performed during the dormant season, the removal of dead, diseased, or damaged wood (the “three Ds”) should occur at any time of the year. Removing compromised wood eliminates potential entry points for insects and disease, maintaining the tree’s overall vigor.
Thinning the canopy is another important maintenance task, as it improves air circulation and light penetration, reducing fungal issues. This involves removing crowded or rubbing branches that cross through the interior of the canopy. You should also monitor for and remove water sprouts (fast-growing vertical shoots on the main branches) and basal suckers that emerge from the base of the trunk or roots.
All cuts must be made precisely outside the branch collar, the slightly swollen area where the branch meets the trunk or a larger branch. Cutting outside this collar allows the tree to seal the wound effectively using its natural compartmentalization process. Cuts that damage the collar or are made flush with the trunk create a larger wound that the ginkgo, which is slow to compartmentalize large wounds, will struggle to close.