Spring hydrangea flowering starts in fall

The “BOBO” hydrangea has strong stiff stems that will hold the ower panicles upright while owering from July through September.
Photo by Ginny Rosenkranz

There are some wonderful hydrangea macrophylla that bloom in the spring with huge balls full of tiny flowers in brilliant shades of blue or pink- depending on the acidity of the soils.

These boring bloomers are not always reliable as they bloom on the stems that grew the year before and started forming their flowers in August and September for the spring flowering. If the winter is harsh, the flow buds can freeze, creating a lovely green shrub without any pretty flowers.

A more reliable flowering hydrangea blooms in late summer and fall with tiny flowers packed into long panicles or bouquets shaped like ice-cream cones.

These late summer and fall blooms usually have pure white, pink or green flowers, and they bloom on the growth that started in the springtime.

These are the hydrangea paniculate and usually grow about 6-15 feet tall and wide with dark green leaves and cone shaped flower panicles that grow 6-8 inches long, blooming from July through September.

They thrive in full sun for the best flowers, and prefer organically enriched soils that are moist but well drained.

One of the most popular is the “Limelight,” with flowers that start out pure white then mature to a chartreuse lime color and age to a soft rose color.

The four-petaled flowers fill the cone shaped panicle to about 8 inches long and can be left on the plant throughout the winter to provide texture in the dreary months of January and February.

The plants are slightly compact growing 6-8 feet tall and wide and are great as a summer hedge or as a bright flowering shrub accent.

“Strawberry Sundae” is a bit smaller plant, growing only 4-5 feet tall with our white flowers that change to pink and mature to strawberry red.

Strawberry Sundae’s flowers are backed onto a cone shaped panicle that can grow up to 7 inches long and 5 inches wide while filling the plant with beautiful white, pink and strawberry red flowers for up to two months.

“Sweet Summer” os also a newer, compact cultivar that produces flower panicles up to 5 inches long and 4 inches wide.

The flowers start out pure white and mature a light pink, and they start flowering at the base of the panicle with new flowers on top, creating pink and white flower bouquets all over the 4-5-foot shrub.

The smallest of the Hydrangea paniculata is “BOBO,” growing on 2-3 feet tall and 3-4 feet wide, fitting into tiny sunlit gardens or creating a low hedge that is covered with pure white flower panicles that can grow up to 11 inches long and mature to a soft pink to a light lavender.

“BOBO” has strong stiff stems that will hold the flower panicles upright, flowering from July through September.

All of the Hydrangea paniculata flowers can be cut for indoor flower bouquets or left on the plants to provide interest and texture after the leaves have fallen off the plants in the late fall through the cold winter months.

(Editor’s Note: Ginny Rosenkranz is a commercial horticulture specialist with the University of Maryland Extension.)