Hardier And More Colorful Hydrangeas

Summer Crush™ hydrangea

For over a quarter of a century, hydrangea breeders (Bailey's, Spring Meadows, and other nurseries) have introduced hardier, tougher, and more colorful bigleaf hydrangeas (Hydrangea macrophylla) that bloom on both new and old wood (USDA hardiness zones 5-8). 

Old wood flowers are set on last year’s growth and new wood flowers develop on current season's growth. It is important not to prune these hydrangeas late in the summer, as flower buds have already formed for the following spring.

Forver a quarter century, Proven Winners Colorchoice™ and Bailey’s Nurseries (Endless Summer™, Bloomstruck™, and Summer Crush™ brands) have introduced the newest hydrangea genetics. The Let's Dance™  series is worth a try in smaller gardens. A second option is to grow a different type of hydrangea Hydrangea serrata, or mountain hydrangea. New in this category from PW Colorchoice is the Tuff Stuff® series which have demonstrated superior bud hardiness and rebloom. Tuff Stuff Ah-Ha® reblooms heavily and has large doubled sepals on lacecap blooms, either pink or blue depending on soil (media) pH._­­­­­

Pruning Big Leaf Hydrangeas

photo credit: Dr. Ken Tilt, Auburn University

When mophead and lacecap hydrangeas (Hydrangea macrophylla) get too tall, leggy, or have outgrown their garden space, prune them now from mid-July thru mid-August. Our native oakleaf hydrangeas (H. quercifolia) are pruned at this time as well. Remove withered or faded flowers; some new flowers may replace those that you have deadheaded in September.

These two hydrangea species set their flower buds for next spring on old or current season’s growth on the terminal bud. Pruning in the fall or winter may remove flower buds or stimulate soft late shoots which die over the winter. Make all cuts at 1/4 inch above the last set of leaves (see photo) or cutback flush to a main branch.

Pruning improves the health of the plant, increasing vegetative growth. On older 4-5 year old hydrangeas, remove larger, thicker canes and prune them at the base of the stem. Remove one-quarter to one-third of these older branches. In 3-4 years the hydrangea will be completely rejuvenated.

Dead, dying, diseased stems and flowers can be removed at any time of year.

A Perfect Year for Hortensia Hydrangeas

2010 has been an exceptional year for big leaf hydrangeas (Hydrangea macrophylla), also called “hortensia” hydrangeas. Consecutive year blooming rarely occurs here in the southern Appalachian region (USDA zones 6 and 7). ‘Nikko Blue” hydrangea, which has not bloomed for over 15 years, has been beautiful in my garden this summer.

Why have big leaf hydrangeas been so “on” this summer? I asked Dr. Sandra Reed, USDA hydrangea breeder at the TN State University Nursery Crops Research Station in McMinnville. Sandra’s response… “the weather”. The 2009 autumn was unusual. October and November temperatures gradually declined. The winter was cold and temps stayed cold, not fluctuating wildly. Across most areas a perfect spring followed with no severe freezes or frosts.

Finally, new hardier cultivars are available such as Endless Summer®, ‘Penny Mac’, and ‘Pia’ (lacecap type). These varieties are remontant, able to bloom on either old or new wood.

If your hydrangea(s) did not bloom this year, check the plant’s light exposure and nutrition. Hortensia types want a minimum of one-half day sunlight, preferably in the morning. Feed shrubs in early spring with a water soluble or slow-release fertilizer according the manufacturer’s package directions.