New Roses Turning Black with White Mold? They May Be Dead on Arrival

Roses bought 3 weeks ago from Home Depot had limbs turning black with white spots like mold. Gardener asked why and how to stop it.

Dead Canes Colonized by Fungus

Black growth = dead tissue. Fungi and bacteria colonize dead wood, producing surface spores. The roses likely died before purchase.

Last Resort

Cut all canes to 2 inches. If pith is pale green, they may resprout. Spray with black spot fungicide monthly. If canes are brown inside, they're dead—return them.