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.