Hydrangeas for Kansas City
I am often asked what my favorite plant is. Picking a favorite is like asking a parent to name their favorite child. You cannot, nor should not, do it.
But asked me to name a plant I must include in my garden, then I can quickly name a few. One on my list is the hydrangea, Hydrangea arborescens, with the common name smooth hydrangea or known by the most popular variety Annabelle.
This shrub adapts to a variety of locations, is not fussy about growing and has the showiest blooms of any plant. What more could you want? That’s why you will find it dotting my garden.
Smooth hydrangea is an eastern U.S. native and can be found growing in Missouri, Iowa and Oklahoma. In its native habitat, it is a mixture of less showy fertile flowers and showy sterile blooms. Cultivars on the market now are bred to create large flowers packed with sterile blooms the size of a softball or bigger.
This plant is adaptable to part shade or full sun. As the exposure to sunlight increases, so does the stem strength. Due to the weight of the flower head, the stem strength in shade decreases, and some varieties can be prone to flopping. It is still an excellent addition for those looking for flowers in a shady location.
Like most plants, well-drained soil and even moisture are its preferred requirements. The more sun on the plant, the more water is needed. Drought stress will result in browning of the foliage and flowers in summer.
What I like best about smooth hydrangea is pruning. Since it blooms on new wood, it is best cut to the ground in the late winter as new growth emerges. I treat it like a perennial, removing all old-growth back to a few inches from the ground level. Each new shoot terminates in the showy flower. Left unpruned, it will flop more with smaller flowers.
The variety Annabelle has been around for years and why many know this species by this name instead of smooth hydrangea. Breeders are improving on this classic shrub. Other white flowering varieties include Incrediball, touted to have flower heads the size of a volleyball. In our Extension Master Gardener demonstration garden, we have the flower heads larger than Annabelle, a taller plant at just over 3 feet.
On the opposite end of the variety, Wee White is the miniature form. It has smaller flowers, baseball-sized, on a plant reaching less than 2 feet. If you prefer a lime-colored flower, try Limetta. All the white flowering types blooms turn from white to green for the rest of the summer.
Smooth hydrangeas are no longer just white as pinky-mauves shades are available. I have found these shades develop best with cooler spring conditions. Warm weather tends to muddy the color. Unfortunately, after flowering, the heads turn brown not chartreuse. Pink flowering varieties include Invincibelle Mini Mauvette, Ruby and Spirit II.
If you don’t have a smooth hydrangea in your garden, now is the perfect time to add one of my favorites. You will not be disappointed.
by Dennis Patton, horticulture turf and ornamentals agent
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