[Minorest spoiler]
Plant all your seeds. Self polinate your plants to make sure you have seeds as backup.
First, cross polinate plants to make a Magic Tree of Fragrance. Self polinate it and plant the seeds, minus 2 as a backup. Sell the trees, but use the other seeds for other Magic Trees of Fragrance. Repeat this until you have made enough money to buy a soil upgrade. Then try to make a Fabled Rose of Isola. If this tree dies young, then make more money with Magic Trees of Fragrance to buy another soil upgrade. With Fabled Roses of Isola you will make a lot of money to continue your breeding program.

[WARNING: SPOILER!!!]
Plant all your seeds. Self polinate your plants to make sure you have seeds as backup.
First, cross polinate plants to make a Magic Tree of Fragrance (Four Petal Maple). Self polinate it and plant the seeds, minus 2 as a backup. Sell the trees, but use the other seeds for other Magic Trees of Fragrance(Fabled Lemon Bush). Repeat this until you have made enough money to buy a soil upgrade. Then try to make a Fabled Rose of Isola. If this tree dies young, then make more money with Magic Trees of Fragrance to buy another soil upgrade. With Fabled Roses of Isola you will make a lot of money to continue your breeding program.
Check http://www.ldwforums.com/ubbthreads/ubbthreads.php/ubb/showflat/Number/94929/page/1#Post94929 if you don't know how to make those plants.