Among the gazillion hydrangeas on the market, our native smooth hydrangea (H. arborescens) remains the most reliable bloomer in our Indiana garden. This year, all hydrangeas have been exploding with flowers for weeks.
The straight species smooth hydrangea has a lace cap flower rather than the balls we usually associate with the plant. Popular varieties of ‘Annabelle’ and ‘Grandiflora’ look similar and several years ago, a hydrangea expert said he’s convinced many sold as ‘Annabelle’ are really ‘Grandiflora’.
Apparently, the ball tops were more popular than the flatter flowers because finding the straight species can be a challenge. Start with native plant sales, if interested in the straight species. White Dome (H. a.‘Dardon’), which has been on the market for about 20 years, has lace cap flowers similar to the native species and is quite attractive.
Almost all of the recent smooth hydrangea offerings are garden worthy. My favorite must-have variety includes the wonderful ‘Haas’ Halo’, which at about 4 to 5 feet tall and wide, is loaded with pollinator-pleasing flat lace cap flowers. Mt. Cuba Center in Hockessin, Delaware, rated hydrangeas a couple of years ago and ‘Haas’ Halo’ ranked high in a study of pollinator visits to its 8-inch flowers (see photo above).
The smooth hydrangea does fine in shade and tolerates more sun if watered as needed. I usually cut mine back to about 12 to 15 inches in spring. Leaving them upright provides winter interest. Plus, the flowers can be cut, and spray painted for container or indoor arrangements. Smooth hydrangea varieties are available with pink, ruby, mauve, and lime flowers.
