The bark on the lower trunks of dogwoods will rot if the trees are planted too deeply. When planting a dogwood, you should be able to see the top of the root ball when you finish back filling the hole with soil. Lawn equipment damaging them. Dogwoods will decline or die rapidly if they are injured or girdled by lawnmowers or string-type weed trimmers. Kill the grass around the base of the tree with a herbicide, then mulch around the tree to prevent weeds.
More dogwoods die from lawn equipment damage than any other reason.
If your tree has already been damaged, contact your extension service to get recommendations for borer control. Cornus kousa dogwoods and hybrids of crosses between C. florida and C. kousa are gaining more popularity in home gardens for several reasons. Milky Way is a superior variety with much great flower and fruit production, making it showy and desirable, says Bill Kidd at McDonald Garden Center. Extension agent Jim Orband recently recommended York County plant Rutgan, a member of the Stellar Pink dogwood series. Among the hybrid dogwoods available, this dogwood demonstrates good disease-resistance, nice upright growth habit and lots of soft pink flowers, he says.