Answer: Perennials in pots require more frequent attention than those in the ground. The soil in containers dries out faster and deteriorates more quickly, so perennials require extra water, topdressing with compost and fertilizer in addition to repotting. If your perennials are the type that spread readily, they'll need division more often, since they'll outgrow their containers more quickly that they would outgrow a plot of soil. They also need extra winter protection because the roots are not insulated by the ground. Other than that, they need the same deadheading, staking and other care.
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