1. Identify the suckers: Suckers are new shoots that grow from the rootstock of the tree, below the graft union. They can be identified by their vigorous growth and different leaf shape compared to the main branches of the tree.
2. Remove suckers as soon as possible: Suckers should be removed as soon as they are noticed, to prevent them from taking away nutrients and energy from the main branches of the tree.
3. Prune suckers close to their origin: Use sharp pruning shears to cut the suckers close to where they emerge from the rootstock, taking care not to damage the main trunk of the tree.
4. Apply a wound sealant: After pruning, apply a wound sealant to the cuts to protect them from pests, diseases, and moisture loss.
5. Monitor the tree for new suckers: Continue to monitor the tree for new suckers and remove them promptly to prevent their growth and spread.
6. Consider the cause: If suckers continue to appear, it may be due to an underlying issue, such as poor pruning practices or root damage. Address these issues to prevent future sucker growth.
7. Consult with a professional: If you are unsure about identifying or removing suckers on your Schubert cherry tree, it's best to consult with a certified arborist or horticulturalist to ensure proper care and maintenance of your tree.