Answer: Coneflowers and blackeyed susans and lance leafed coreopsis may germinate without a cold stratification period and so could be started almost any time. In some cases however they will not germinate and so a few weeks of cold chilling can be used to jump start them. In nature they will self sow during the summer, but as a gardener the choice is up to you. They will reach a larger size and possibly bloom sooner if planted during the summer and given that extra few months of growth.
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