Here’s a comprehensive list of trees and shrubs that grow in the Kharkiv region and whose leaves can be used to make tea, ordered by flavor from sweet to bitter:

Sweet taste:
1. Apple tree (Malus)
2. Pear (Pyrus)
3. Plum (Prunus domestica)
4. Cherry (Prunus avium)
5. Red (Cornus mas)
6. Viburnum opulus
7. Linden (Tilia)
8. Currants (Ribes)
9. Raspberry (Rubus idaeus)
10. Blueberry (Vaccinium myrtillus)
11. Strawberry (Fragaria)
12. Sweet cherry (Prunus cerasus)

Bittersweet taste:
13. Black chokeberry (Sorbus aucuparia)
14. Walnut (Juglans regia)
15. Birch (Betula)
16. Aspen (Ailanthus)
17. Willow (Salix)
18. Poplar (Populus)
19. Hazelnut (Corylus)
20. Rosehip (Rosa canina)

Bitter taste:
21. Bird cherry (Prunus padus)
22. Rowan (Sorbus aucuparia)
23. Bitter almond (Prunus dulcis var. amara)
24. Dogwood tree (Cornus mas)
25. Thorn (Crataegus)
26. Bitternut (Juglans nigra)

Keep in mind that flavor and aroma can vary depending on many factors, including variety, preparation method, and growing conditions. It’s recommended to test and experiment to determine your favorite combinations.