Q: I am stumped. Two months ago we bought a ‘Fat Albert’ Colorado spruce. We’ve left it in the container since then while we decided where to put it. Branches on the lower half are turning brown and dying. Michael Dirr’s “Manual of Woody Landscape Plants” lists many spruce problems but they don’t sound like ours. What could it be?

A: One factor that determines if a plant will prosper is its tolerance of cold weather. Experts like Dr. Dirr have rated blue spruce hardy in Zones 3 – 7 (-40 to 0 degrees). Theoretically, spruces should do fine here.

However, many plants that tolerate cold weather can not abide prolonged heat.

Since the USDA Hardiness Zone map only guides gardeners on the cold hardiness of a plant, the American Horticultural Society developed a Heat-Zone map of the country.

Colorado spruce does not like our summer heat. It is rated heat-hardy only in the upper reaches of North Georgia. Although I occasionally see Colorado spruce trees that have grown to a reasonable size, they are the exception rather than the rule.

Further, you didn’t do it any favors by leaving it in a container. The soil probably got very hot and caused the roots to shut down, leading to the problems you see now. I doubt ‘Fat Albert’ will recover.

My advice is to choose another tree to plant. Consider deodar cedar, ‘Emerald Green’ arborvitae, Arizona cypress or ‘Grey Owl’ juniper.

 Heat-Zone Map