Snowmound Spirea

(Rosaceae - Rose Family)

Large View

• Form
  • small ornamental shrub
  • maturing at about 5' tall by 5' wide
  • upright vased growth habit in youth, quickly becoming arching with age
  • medium growth rate

• Culture
  • full sun to partial shade
  • performs best in full sun in moist, well-drained soils, but is very urban tolerant and adaptable to poor soils, clay soils, dry soils, soils of various pH, heat, drought, and heavy pruning
  • propagated primarily by rooted stem cuttings
  • Rose Family, with numerous potential diseases and pests, which usually do not manifest themselves
  • 'Snowmound' is abundantly available in container form
  • the numerous small dried fruits and pedicels can be easily removed in late Winter or early Spring (before bud break) by grasping the arching stems at their bases with a gloved hand and pulling the hand upward along the stems until the fruiting bodies have fallen away

• Foliage
  • blue-green, alternate, elliptical to narrowly obovate, about 1" long, with essentially no petiole, and sparsely serrated or notched at the apex of the leaf blade
  • fall color is green to chartreuse and ornamentally ineffective

• Flowers
  • white inflorescences of 1" diameter cover the arching foliaged stems of the shrub in late May, like a mound of snow (hence the common name)

• Fruits
  • many small clusters of greenish-brown miniature fruits cover the arching stems in Summer and are persistent into the following year, not at all ornamental but noticeable and slightly detracting from the foliage and growth habit of the shrub

• Twigs
  • dark brown-burgandy and ridged, with many stems originating from the base of the shrub and forming a vased to arching growth habit, and having many short, thin, and dense lateral twigs from which most of the flowers and fruits arise

• Trunk
  • not applicable

• ID Summary
  • pure white abundant inflorescences smother the stems and foliage of this vased and arching 3' to 5' tall shrub in late May, then abscise to reveal the blue-green, narrowly obovate, alternate, small foliage that is sparsely notched on the upper one-third of the leaf blade

• Function
  • specimen, group planting, informal hedge, border, entranceway, or foundation shrub

• Texture
  • fine texture in foliage and when bare
  • average density in foliage and when bare

• Assets
  • showy white inflorescences in late Spring
  • vased to arching low growth habit
  • urban tolerance
  • fine textured blue-green foliage

• Liabilities
  • poor fall color
  • persistent fruiting stalks

• Habitat
  • zones 3 to 8
  • native to Japan

• Alternates
  • urban-tolerant dense shrubs of 4' to 6' in mature height (Berberis x mentorensis, Forsythia x 'Arnold Dwarf', Syringa patula 'Miss Kim', Weigela florida 'Variegata', etc.)
  • late Spring flowering shrubs (Spiraea japonica, Syringa x prestoniae, Viburnum dentatum, Weigela florida, etc.)
  • small to medium-sized white-flowering shrubs (Abeliophyllum distichum, Clethra alnifolia, Fothergilla gardenii, Hydrangea arborescens 'Annabelle', Itea virginica 'Henry's Garnet', Rosa 'Kent', etc.)

• Variants
  • Spiraea nipponica 'Snowmound' - as described throughout, this is the standard cultivar of this species (the species form is virtually unobtainable in the nursery trade)
  • Spiraea nipponica 'Halward's Silver' - a slightly more compact form, to 4' tall by 4' wide

• Translation
  • Spiraea is from the Greek, denoting a plant used in wreaths or garlands.
  • nipponica translates as "of Japan".

• Purpose
  • Snowmound Spirea is an accent shrub when in flower in late Spring, and is one of the few small shrubs with a vased and arching growth habit.

• Summary
  • Spiraea nipponica is known as a low arching shrub that has urban tolerance and pure white inflorescences that blanket the plant in late-Spring, being a compact and later-flowering complement to Spiraea x vanhouttei (Vanhoutte Spirea).