There is no "special way" to enter this in TurboTax; removal of the trees would be entered as "repairs and maintenance" (Expenses) and the landscaping (e.g. shrubs, sod, retaining wall) would be be entered as an asset (Assets/Depreciation).
Just enter the costs in Expenses or Assets/Depreciation. How you paid for them at time of purchase (personal credit card) or reimbursed yourself from the rental properties checking account doesn't get entered in TurboTax. These are depreciable improvements to the property.
