1. da vincis invention is its seed (8) 2. Girl's name (5) 3. Sister to number 2 (9) 4. Maestro with an i (8) 5. Used for cricket bats (5,6) 6. Planted as windbreaks (8,6) 7. Pink candles (5,8) 8. 1er, 2er, 10er,12er etc (5,8) 9. Infusion used for sprains and bruises (4,5) 10. Catkin tree (4,6) 11. Type of foreign bird (8) 12. Cobnuts can be picked here (6,5) 13. Stockholm number 3 (7,9)
No. 7 Should be Horse Chestnut (or Sweet Chestnut). I'll leave it to you to sort them out?
Having said that, No.8 looks more like Horse Chestnut - as these terms are applied to the "conkers".
Before the "conkers " are formed, the flower clusters are called "candles".
9 The infusion for sprains and bruises is witch hazel- but as this is the wrong number of letters it might be wild myrrh, which is used as an anti inflammatory.