No other blossom greets summer with more beauty than the classic hydrangea. Ideal for this region, these low-maintenance shrubs will thrive in the heat and humidity of the Greater Philadelphia area. Their show-stopping elegance and lavish abundance of petals will turn any outdoor space into a magical setting.
“I have always felt that the backbone of the garden is made up from the shrub layer,” says Andrew Bunting, PHS Vice President, Public Landscapes. “In the spring, we have the myriad of azaleas and rhododendrons, but in summer, all eyes turn to the Hydrangea. Any conversation about summer flowering shrubs is not complete without the Hydrangea.
Native hydrangeas are favorites for their summer blooms. The smooth hydrangea, Hydrangea arborescens ‘Annabelle’ (pictured above) was introduced by J. C. McDaniel in 1962. It has remained the best-of-the-best in the hydrangea world for decades. It blooms on current season growth, therefore, can be pruned hard in March. “I prune the branches back to about four inches which keeps the shrubs at about four feet tall when they flower,” says Bunting. “In July, every stem is covered with a large, white, mophead flower. The flowers emerge lime green, turn pure white, and finally fade back to lime green and have tawny flowers for the winter.” ‘Annabelle’ received distinction in the Pennsylvania Horticultural Society’s Gold Medal Program in 2001.
Since 1962, many new varieties have been made including what is considered one of the holy grails of the hydrangea world, the “pink Annabelle”, Invincibelle® Spirit. The flower clusters are a little smaller than ‘Annabelle’, but the flowers are soft pink. Incrediball®, with massive heads, was developed as a non-flopping version of ‘Annabelle’. For smaller spaces, Invincibelle® Limetta is a dwarf version of the much-loved ‘Annabelle’.
“In recent years, Hydrangea paniculata has gone through an amazing horticultural renaissance in gardens,” says Bunting. “One of my favorites is ‘Limelight’ where the flowers transition from lime green to alabaster white.” If the planting space calls for something smaller in stature for a suburban or urban garden, he recommends Little Lime®, which matures at four feet tall with lime-green flowers, or ‘Dharuma’ with white flowers that fade to pink, and also remains small.
While the oakleaf hydrangea, Hydrangea quercifolia ‘’Snow Queen’ is native to the southeastern parts of this country, It is perfectly hardy in our area. Starting in July, this shrub — which can reach ten feet in height — has white cones of flowers atop leaves that look like red oak leaves and turn purple-red in the fall. “This older, but still popular cultivar, is also a PHS Gold Medal recipient,” explains Bunting. Other beauties include ‘Snowflake’, with double flowers which make them so heavy the clusters hang downward, and ‘Amethyst’ with white flowers which quickly turn deep pink-purple. For the smaller garden, consider ‘Pee Wee’, ‘Sike’s Dwarf’, and ‘Munchkin’.
To learn more about flowering shrubs, join author and educator Eva Monheim on Friday, July 17 at 12:30 p.m. for Selecting Shrubs for Four Seasons of Interest. This educational lecture and discussion, presented virtually, will be moderated by Bunting. Register here.