Our call centre capacity is currently reduced to ensure staff safety. Plant mums in fertile, moist, well-drained soil, as the soil warms in the spring. Please accept our apologies in advance should this result in your having to wait longer than normal in a call queue. The perennial type are often called hardy mums. Naturally dome forming and compact, they will make fabulous potted plants for outdoors, or neat little domes in beds and borders. They are best planted next to early bloomers. Since mums bloom so late in the season, they are non-descript, though not unattractive, in the border until blooming time. From late spring to mid-summer (about July 4)… Lines are currently open 9am-5pm, Monday to Friday. Nothing heralds the arrival of Autumn in the garden than good old-fashioned Chrysanths - and these amazing Hardy Garden 'Mums are just the ticket to fill your garden with colour late on in the season and on into Winter. Mums generally prefer full sun, but they will tolerate some light shade and may actually prefer some shelter in very warm climates. As these spring blooming flowers fade, the mums will fill in and hide their unattractive fading foliage. Order By Phone. There are several species of chrysanthemum, with some being hardier than others. Chrysanthemums are flowering herbaceous plants, but are mums annual or perennial? The answer is both.