Southeast: Michael Dirr

Huntsville, Alabama, Zone 7

Michael Dirr is one of those rare, driven individuals who make the rest of us look like we’re mired in Jell-O. I discovered this when my husband and I spent a whirlwind six hours with the celebrated, 50-some-thing teacher, researcher, and prolific author (my elbow has rested on his voluminous Manual of Woody Landscape Plants [Stipes Publishing, 5th ed. 1998] ever since I broke into the garden-writing racket) last summer at the University of Georgia at Athens.

What Dirr called his “50-cent tour” (the dollar tour, he says, takes all day) began with a bouncing pickup ride to a tree-canopied test plot planted with blocks of shade-loving shrubs and bordered by a hoop house stuffed to the gills with potted hydrangeas. One of Dirr’s current passions is the search for culti-vars of Hydrangea macrophylla that hold their heads up after a rain and bloom even after a severe winter.

Dirr lectured as he strode from row to row and we examined dwarf crape myrtles—another current passion—and searched among rows of golden spireas for individuals with resistance to sunburn. A tall man with the build of a football player, Dirr was sensibly outfitted in shorts, polo shirt, sun visor, and running shoes, and seemed unfazed by the 93°F heat. Mercifully, though, he took note of the diminishing turgor of his visitors and hauled us to his home in nearby Watkinsville, where his artist wife, Bonnie, kindly revived us with iced tea. Then, quickly, it was out into the Dirr garden—which I felt I knew as well as my own, so often is it mentioned in his writing. A spacious lawn meandered among masses of shrubs, most noticeably looming, white-speared bottlebrush buckeyes (Aesculus parviflora).

Soon back in the truck, we spun through portions of the university-run State Botanical Garden of Georgia, of which Dirr is former director, then barreled over to the beautifully landscaped garden of University of Georgia director of athletics and former Bulldog head coach Vince Dooley. The coach, an avid gardener and close buddy of Dirr’s, wasn’t home, but we met the next best thing: extra-hardy Hydrangea macrophylla ‘Dooley’, blooming in blue profusion by the garage.

Our last stop was the university’s greenhouses, where Dirr, his colleagues, and friendly, bright-eyed student assistants propagate a multitude of plants. Dirr works closely with the nursery industry to select and promote superior ornamental plants, most recently through his Noble Plants program. His web site,, is a bonanza for the plant-addicted.

To my joyous surprise, in parting, the professor loaded us down with new shrubs to take home and try: Hydrangea macrophylla ‘Endless Summer’, guaranteed to bloom on the current season’s growth; purple-leaved Loropetalum chinense var. rubrum ‘Suzanne’, named for his youngest daughter; festive Buddleia davidii ‘Bicolor’; and more—enough to fill the car.

Whew! The 50-cent tour was worth every penny. The dollar tour would have killed us.

To Do in the Garden: Early Spring

  • While it is still too early in all but the warmest parts of the South to set out tender annuals and tropical perennials, you can and should purchase and set out hardy perennials, shrubs, and trees while selections are at their best and temperatures are cool.

  • Divide chrysanthemums, discard their woody centers, and replant a few young crowns. Swap the rest for starts of your friends’ overgrown perennials.

  • Get growing with such early-season vegetables as peas, greens (spinach, turnips, cabbage), onions, and Irish potatoes.

  • Repaint metal or wooden outdoor furniture. Recover or replace damaged cushions. Discard aging resin chairs that may have become brittle.

Worth Growing:  Betula nigra ‘Dura-Heat’
One noteworthy plant we met in Coach Dooley’s yard was Betula nigra ‘Dura-Heat’ (USDA Zones 5-9), a new selection of our native river birch that Dirr predicts will replace B. n. ‘Heritage’ as the industry standard. More compact than ‘Heritage’, this graceful, multistemmed tree features prominently peeling bark and glossy, olive-green leaves that turn yellow in fall. Resistant to aphids, leaf spot, and bronze birch borers, and tolerant of heat (but not drought), B. n. ‘Dura-Heat’ likes moist acid soil. 

Related Posts:

  • No Related Posts

One thought on “Southeast: Michael Dirr

Leave a Reply