Our Heralded Hydrangeas

Selected cuttings from the Washington Park Arboretum, (July 17 - 31, 2017)
David Zuckerman
Selected cuttings from the Washington Park Arboretum
(July 17 – 31, 2017)

1)   Hydrangea aspera subsp. robusta

  • This 10-foot shrub with large fuzzy leaves produces flat, light blue flowers to 12” across on petioles which may reach 14” or more!
  • Native to the region between the Himalayas, across southern China, to Taiwan.
  • This 1941 specimen is located in the Camellias, next to Franklin tree along Arboretum Drive.

2)   Hydrangea heteromalla                               Wooly Hydrangea

  • A tree-like hydrangea native to China and the Himalayas.
  • Another 1941 specimen that has an enormous trunk and is 20 feet tall!
  • Located on north-facing slope below parking lot #4 (Rhododren Glen).

3)   Hydrangea macrophylla ‘Goliath’                    Bigleaf Hydrangea cultivar

  • In hydrangeas, flower color is affected by the relative availability of aluminum ions in the soil.  Acidic soils with a pH of less than 5.5 produce blue flowers; soils with a pH greater than 5.5 produce pink flowers.  White flowers are not affected by pH.
  • A “mophead” or “snowball “ flower-type (rounded corymbs), containing all blue sterile flowers.
  • This specimen is just south of ‘Bluebird’ (#5 below) with puny flowers for its namesake. 🙁

4)   Hydrangea quercifloia                    Oakleaf Hydrangea

  • The large panicles contain both the showier sterile flowers and the many smaller fertile flowers opening just underneath.
  • In addition to its fantastic flowers, bold foliage and attractive peeling bark, this species develops stunning red to purple fall color.
  • Oakleaf Hydrangea is native to the southeastern United States.

5)   Hydrangea serrata  ‘Bluebird’                    Mountain Hydrangea cultivar

  • A favorite “lacecap” flower-type (flattened corymbs), containing blue sterile flowers and numerous fertile flowers within.
  • This species is native to the mountains of Japan and South Korea.
  • Mass blooming past Rhododendron Glen sign, east of Arboretum Drive.