Dahlia Garden a Complete Failure!
I planted an extensive dahlia garden this year that, unfortunately, met with complete disaster. I planted 22 tubers, all of which came up and did very well -- for a while. Then the plants started turning brown and crispy from the bottoms up. Some folks suggested that the hot Sacramento sun might be too much (they're in a full-sun location). But if it was too much hot sun, wouldn't they have crispified from the top downward, not the other way around?
Someone else suggested the redwood bark chips I laid down as a mulch was depleting the nitrogen. Could this be the culprit?
The dahlias are in their own section of a border garden. Most of the other plants had no problems at all. It was just the dahlias that turned into dried up twigs.
Any input gratefully appreciated.