Dr. Dirr

Dr. Michael Dirr discusses: Parrotia Persica - Persian Parrotia, Persian Ironwood

Parrotia persica-Persian Parrotia, Persian Ironwood Michael A. Dirr What a great small tree! Roaming the Georgia campus in early March, I notice specks of bronzy green emerging from the dusty gray buds. Leaves will be fully formed by early to mid-April and persist until November-December when fall color signals time to rest. Leaves […]

Dr. Dirr Discusses: Aesculus pavia- Red Buckeye

The red buckeye is among the most beautiful eastern North American tree species, especially in flower, when the brilliant red panicles glow in the woodsy understory. The species occurs naturally in pinelands, pine-deciduous woods, wooded bluffs, stream banks and bottomlands throughout the range. The USDA Plants Database shows distribution in the wild from North Carolina […]

Dr. Michael Dirr's latest findings: Chionanthus retusus- (Chinese fringe tree)

Chionanthus retusus- Chinese fringetree Michael A. Dirr In 2018, I was asked to assist with our county’s (Oconee, Georgia) tree planting project for a new four-lane, 3.5-mile highway. The county commissioner emphasized the concept of a tree-lined gateway to the county seat, Watkinsville. After many meetings, nursery visits and suggestions, we agreed upon 760 trees, […]

Dr. Michael Dirr's Latest Findings: Magnolia Virginiana- Sweetbay Magnolia

In previous tree profiles, I discussed Magnolia acuminata and M. × soulangeana and herein highlight an increasingly important landscape species, M. viginiana. It is becoming more common in contemporary landscapes because of new cultivars with smaller sizes, increased cold hardiness, and fully evergreen foliage into zone 6 landscapes. The impetus for this discussion resulted from […]

Dr. Dirr's Spotlight: Acer Pseudosieboldianum - Korean Maple

Certainly, easy to become monochromatic about small maples when Acer palmatum and the numerous cultivars are readily available via garden centers and mail order sources. Why look further? Well, if you live in the zone 3 to 5 regions of the U.S., then Japanese maple culture is challenging, if not impossible. Enter, Acer pseudosieboldianum, Korean […]

Dr. Dirr's Tree Spotlight: Quercus Lyrata-Overcup Oak

The overcup oak, Quercus lyrata, languished in landscape obscurity until the 1990s when several Georgia nurserymen realized and developed its potential. The University of Georgia campus is rich with Q. lyrata, no two alike, so the thinking went can the species be clonally/vegetatively propagated. Mike Glenn, Select Trees, Athens, and John Barbour, Bold Spring Nursery, […]

Dr. Dirr Tree Spotlight: Magnolia x soulangeana- saucer magnolia

The hope of spring is tethered to this species and the many cultivars. Difficult to imagine a garden, park, campus, golf course, city street, commercial property almost anywhere in the U.S. without a least one saucer magnolia. From Chicago to north Florida to the West Coast, the species can be successfully grown. The late Roger […]

Dr. Dirr's Tree Spotlight: Liriodendron tulipifera (Tuliptree)

From the arborists’ point of view, the tuliptree has more than its share of liabilities including excessively fast growth, limb breakage, drought-induced premature leaf abscission, and aphid/honeydew issues. Yet it is one of the most noble trees in the eastern North American deciduous forest. In Joyce Kilmer National Forest, the towering slender bole and narrow […]

Dr. Dirr's Tree Spotlight: Acer triflorum - Three-flower Maple

A beautiful maple, resoundingly/photogenically magnificent in shades of orange and red in autumn. Colors long persistent, from initiation to the crescendo, easily 3 to 4 weeks. Although Acer griseum receives the majority of garden accolades, this is the most adaptable, cold hardy, heat tolerant and reliable. In truth I love both, also certainly Acer maximowiczianum […]

Dr. Dirr Tree Spotlight: Thuja occidentalis-Eastern Arborvitae

Dr. Dirr's thoughts on the Eastern Arborvitae: Not quite sure why I never fully respected this soft-textured needle evergreen but an epiphany occurred during a seven-day circuitous, whirlwind-like, 2018 tour of Vermont. From Brattleboro to Burlington, in cultivation and the wild, the species was ubiquitous. Screening evergreens are few in this cold climate state, with […]

« Previous 1 2 3 4 Next »

Articles & Tips