Hydrangeas offer rainbow of colors
This is the time of year our panicle hydrangeas begin to bloom. It is the last of the five types of hydrangeas in Ohio to bloom — but possibly the best.
It is a nearly carefree plant. Deer don’t love it. They do not need much pruning. Bloom color selections range from white to pink and even red to purplish. The only hard decision is choosing the right-sized plant for the right site and let it grow.
Panicle hydrangeas are the ones just budding this time of year. Nearly all will look creamy white to lime green as the flowers begin to open. They can be from 3 feet tall to more than 8 feet tall. The flower heads can be full and referred to as a mophead or open and airy (less showy flowers) and called a lacecap. The lacecap flower heads have many more fertile florets and thus are a pollinator magnet.
As these flowers come into full bloom in August, they fill a bloom time when many summer flowers have faded and autumn flowers have yet to bloom. Thus, they are an important pollinator plant.
From tall to short, there is a panicle hydrangea for every garden. If you want a showcase plant or a border between neighbors in summer, look at limelight at up to 8 feet tall or tardiva at about 6 feet tall. Limelight will have large, full blooms that fade to a lime green color and tardiva will have lacecap flower heads that fade to greens and pinks. This makes tardiva a wonderful pollinator plant.
Any of the panicle hydrangeas that get at least 6 feet tall can be pruned to one stem to make your own tree hydrangea.
If you want a short plant, Bobo at up to 36 inches and Little Lime at up to 60 inches are just two of the many options for shorter versions. Be sure to get the correct height from the plant’s tag. Bobo has so many blooms, they nearly hide the plant’s foliage.
Achieving the best bloom color is done by placing these plants in the correct site. Although many labels for these plants say you can have them in full sun, many cultivars can perform even better in part shade. By giving these plants morning sun and afternoon shade, you not only extend the bloom time — you allow for more vibrant colors in the blooms and faded blooms.
One example is Hydrangea paniculata Vanilla Strawberry white, which has blooms that begin as white, then fade to pinks and pinkish red colors. If located in more afternoon shade, the pinkish red color lasts longer and fades to an almost pinkish purple color in early fall.
Pruning for panicle hydrangeas should be done in the autumn after the leaves fall as they do not set next year’s blooms until late spring of the next year. In general, pruning to shape is all you need to do. Over-pruning (cutting more than a third of the plant down) on panicle hydrangeas with large, full flower heads will cause flowers to be even larger the next season. The large flower heads (many more than 12 inches tall) have a lot of wow power in the garden, but no matter how strong the stems — you will get flopping and a few broken stems.
There are many, many more cultivars of hydrangeas than I have room for in this article. The ones I mention are as examples, and no endorsement is intended. Whatever you choose as your cultivar, do a little homework and get the best possible one for your tastes and your garden site.
To learn more about hydrangeas, download my factsheet, chart and pictures at http://go.osu.edu/hydrangeafacts.
Barrett is the Ohio State University Extension educator for agriculture and natural resources in Mahoning County.