Buying Plants: Research Disease Resistance and Hardiness Before Purchase

My friend Von Woods asked: "Do you have a list of disease-resistant dogwoods? Heard a new fungus is killing wild trees in the Smokies."

Von's info is true, but not panic time in Atlanta. Discula destructiva killed thousands of native dogwoods along Atlantic seaboard. Scientists observed most infected trees on elevated mountainsides and in heavy shade. Most of our trees, landscape and woodland, are reasonably safe.

Researchers tested for discula resistance in early 1980s. Native flowering dogwood (Cornus florida) and Korean dogwood (Cornus kousa) are susceptible, but their inter-species hybrids are not. Rutgers University released patented disease-resistant dogwoods: 'Stardust', 'Stellar Pink', 'Celestial', 'Constellation'.

Even with hybrids, I wouldn't hesitate to plant less resistant dogwoods like white 'Cherokee Daybreak', 'Cherokee Princess', 'Cloud 9' or pink 'Stokes Pink', 'Cherokee Chief', 'Cherokee Sunset'. Discula appears in scattered Atlanta spots; most dogwoods get enough sun to keep leaves dry and fungus-free.

Key factor: summer moisture availability. If trees in full sun, water weekly during drought. Thick mulch under tree to branch ends keeps soil cool and conserves moisture.

COLD HARDINESS

Clint Hasty in Cumming wants to avoid "I told you so!" He writes: "Wife and I bought six wild potato bushes last summer at home improvement store, $36 each. Tag said hardy to -10°F. Beautiful shrubs with hundreds of small purple flowers. After first frost they lost all leaves. Wife thinks they're dead; I say they'll return like crepe myrtle. Tell me I'm right!"

Whew! Over $200 spent. But SURELY a store wouldn't sell non-hardy plants here?

Despite tag, potato bush (Lycianthes rantonnei) is not winter hardy outdoors in Atlanta. Grown in warmer spots but won't survive Atlanta winter. If Clint has tag, show nursery manager for refund.

As planting season swings, know plants beforehand. Unless positive about growth habit, pest resistance, hardiness, ask knowledgeable gardener or nursery person. I find "The Southern Living Garden Book" comprehensive and easy-to-use.

MORE INFORMATION
Dogwood Diseases in Alabama
Growing Dogwoods