Just before the weather gets warm enough for real marigolds, and after the weather starts to get too cool and rainy for them, pot marigold, Calendula officinalis, is at its best. It can bloom at any time of year, depending on when it gets planted, but prefers cool and humid spring and autumn weather. It is not so keen on frost in winter, or the arid warmth of summer that real marigolds enjoy.
They are just as versatile as real marigolds are, and work nicely in pots, but they are known as pot marigold because of their history as culinary herbs. They also have medicinal applications, and can bu used for dye. Mature plants do not often get bigger than a foot tall and wide, with somewhat coarse light green foliage. The two or three inch wide flowers are bright yellow or orange, and can sometimes be double.
It looks like sweet alyssum, but is not even close. The tiny white flowers and finely textured foliage work almost as well for similar uses in the landscape. In fact, the plants are most often grown as short term warm season annuals. However, candytuft, Iberis sempervirens, is really a perennial that can be cut back in autumn, regenerate through winter, and bloom for spring and early summer.
Tony Tomeo 