Why is my Little Princess Spirea shrub fading away?

I recently planted four beautiful shrubs,but now two of them have drying wilted leaves spreading on them. Am I over watering or ??? All are planted in the same bed,receiving full sun.

Why is my Little Princess Spirea shrub fading away?
Spirea nipponica 'Snow Mound'


Spirea x vanhouttei








Description: Spirea is a deciduous flowering shrub which has many varieties of flowers, foliage and some have graceful growing hadits. There are about 70 species and as might be expected in such a large genu, vary greatly in height, form, and flowering times


Flower: .Two flower forms. The spring-blooming spireas usually are borne in umbels(clusters in which all flower stems start from one point and are about the same lenght.) The summer-blooming sprieas are either flat-topped clusters or long plumy clusters borne at the tips of branches. Colors range from white, to pink, to red.


Foliage: Undistinguished leaves for most species, few have colored leaves in autumn and no decorative fruits.


Misc. info: All spireas are easy to grow and have no particular pests.


S. Anthony Waterer One of the most popular and widely grown of summer-flowering shrubs. Bright crimson flowers ocurring midsummer onwards.


S. Dolichica


S. Froebelli Pink Similar to Antony Waterer but growth habit is somewhat taller and wider.


S. Goldflame This is a very popular variety mainly for its foliage which emerge reddish-orange in spring and become bright yellow then green. But this beauty also has lovely deep rose-red flowers.


S. Little Princess Low dwarf mounding. Has pink to rose-crimson colored flowers in late spring thru summer and onward.


S. Norman


S. Limemound, G. mnd A compact dwarf shrub that forms pink clusters of flowers from mid summer onward. The foliage is yellow to yellow-green.


S. Shirobana Later flowering from mid summer on. Flowers are a mixture of white, pink and deep rose some times on the same head. This a dwarf growing shrub of about 3'.


S. Snowmound A small dense white flowering maound forming shrub.


S. Vanhouttei Vigorous growing shrub of 6-7' tall with arching branches. Flowers in mid-May borne in dense umbels along these gracefully arching branches.


S. Assorted


Site: Well-drained, deep moist soil. Full sun.