Crossville Chronicle, Crossville, TN

July 22, 2013

Plateau Gardening: Find hydrangea inspiration at Discovery Gardens

By C. Rae Hozer
Chronicle contributor

— The eye-catching white, pink, blue and part-blue-part-pink hydrangeas blooming in yards on my street right now are mostly Hydrangea macrophylla cultivars. The inflorescence of these big-leaf hydrangeas combines conspicuous sterile flowers and tiny, fuzzy, fertile flowers. The inconspicuous fertile/true flowers produce seed and attract pollinators. The sterile ones are long lasting and are the reason hydrangea blooms make such attractive dried flowers.

In mophead varieties (also referred to as Hortensia cultivars) showy flowers are on the outside of each round cluster hiding from view the real flowers on the interior. Lacecap varieties have a flatter floral form with an inner circle of small, fertile flowers surrounded by an outer ring of the flashy, sterile ones. The lacecap effect is striking and delicate when compared to the in-your-face visual impact of mopheads, but I find both appealing.

The large (between four and 12 inches), creamy white cone-shaped flower panicles on Oakleaf hydrangea are also a combination of fertile (interior) and sterile (outer) flowers. Despite their lighter color when first open, over time oakleaf flower clusters turn a rose color. Unlike other hydrangea species, H. quercifolia leaves have fall color and remain on the plant a long time. The foliage turns a dark, deep-reddish hue in autumn. Exfoliating bark makes this species a winter attraction, as well. Though most hydrangea need substantial growing space, a new (2010) release by the U.S. National Shrub breeding program in McMinnville called Munchkin (H. quercifolia 'Munchkin’) is smaller (3 feet tall by 4.5 feet). The foliage is dark green in summer and mahogany-red in autumn. Munchkin might be a good choice if you have a small yard.

If you share my admiration for hydrangea blooms and do have a suitable spot with at least five hours of sun (morning through noon) along with afternoon shade and moist well drained soil, surf the Internet to make a list of some having characteristics that appeal to you. Readers who wish to view a full sized oakleaf hydrangea (in the 2005 Tree and Shrub area) as well as other perennial plants in person rather than in pictures, should visit Plateau Discovery Gardens located just south of I40 exit 311 Plateau Rd., off Hwy. 70 N at the University of Tennessee Plateau AgResearch and Education Center, 320 Experiment Station Rd., Crossville.

Various theme gardens and university trial gardens within the Discovery Gardens complex are open for self-guided tours daily during daylight hours. Entry and parking behind the office are available without charge. Plant specimens growing there are labeled. Wherever you find plants to add to your landscape wish list, write down Latin plant names and note attractive features so you will be able to ask for the specific cultivar (or another with the same attributes in case the exact variety you want is not sold where you shop).

Few gardeners want a hydrangea that is just a big green bush with no blooms, but failure to flower is a common complaint of hydrangea owners. Too few blooms can be caused by incorrect pruning. Most (but not all hydrangeas) produce flower buds in the prior year for the current year’s floral display. As shrub experts say, “They bloom on old wood.” Get a chuckle while reading the online story "The Big Hydrangea that Wouldn’t Bloom" at Hydrangeas! Hydrangeas! (http://www.hydrangeashydrangeas.com/). This tale tells how Amy-Beth and the love of her life, David, learned to not prune hydrangeas after July 31. Find many hydrangea images and lots of good information on planting, transplanting and fertilizing hydrangeas from hydrangea enthusiast Judith King at that website.

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Plateau Gardening is written by Master Gardeners for gardeners in Tennessee’s Upper Cumberland Region. Contact UT Extension Cumberland County at P.O. Box 483, Crossville, TN 38557 (484-6743) for answers to horticulture questions, free publications and how to become a Master Gardener. Send email comments or yard and garden inquiries to Master Gardener Rae, MGardenerRae@frontiernet.net.