Plant weeping cherry seedlings in early spring in all areas, while the seedlings are dormant. In warm areas of the country, plant in the fall as well, after the seedlings enter their winter dormancy. Mid-summer and mid-winter plantings lead to seedling suffering and possibly death.
Weeping cherries need bright sun for six to eight hours every day, with adequate space and quick drainage. Shade restricts blooming while standing water leads to root rot and tree failure. Give each tree 25 to 30 feet of space for growing.
Weeping cherry trees don't require rich soil, but do require good in-soil drainage. Mix decomposed granite, garden loam or organic compost into the planting site for looser soil, to encourage better soil drainage and root growth. Cherry trees in tight soil can suffocate or drown.
Give weeping cherry trees balanced 10-10-10 or 12-12-12 fertilizer in spring, along with new compost amendments, to encourage continued growth. Weeping cherries without adequate nutrition may restrict both growth and blooming. Irrigate the trees with 2 to 3 inches of water every week to keep them healthy, and use organic mulch to maintain soil moisture and restrict weed growth.