When Do Hardy Mums in the Garden Start to Bloom?

Hardy Mums

• Florist mums are sold in pots and bloom when forced. They are grown in greenhouses and manipulated to bloom at certain times so they can be sold as gifts. These are different from mums planted in the garden. Mums sold as bedding plants are often called hardy mums, because they can tolerate cooler autumn temperatures. Although the blooming period of mums varies depending on a number of factors, the majority of hardy mums begin blooming in late summer to early fall.

Climate Considerations

• Climate plays a part in when hardy mums begin to bloom and for how long they continue to bloom. If your mums survived the winter, they may begin producing flower buds as early as late June. In hotter climates, they may not start blooming until the hottest part of the summer is over. Freezing temperatures may affect blooming as well. Some mums cannot survive hard freezes, but hardy mums are strong enough to survive as perennials in USDA growing zones 5 through 9. Still, freezes may kill them down to the ground, at which point it is prudent to cover them with mulch to help protect the roots from more freezing weather.

Cultural Considerations

• Improper care can adversely affect the blooming of hardy mums. Plants that are not cared for properly will not bloom in a timely manner. Chrysanthemums thrive in full sunlight and in rich, well-draining soil. Full sunlight encourages blooming and keeps them flowering longer into the winter. Well draining soil is necessary to prevent the soil from becoming waterlogged, which leads to root damage. Too little water will cause stunted growth, however. Keep the soil barely moist at all times.

Insect Pests and Diseases

• Fungal diseases often affect hardy mums. Most fungi spread on water, including rain or overhead irrigation. Damage may appear as spots on the leaves and blooms, wilting, or a thin layer of gray powder or sooty-looking mold, depending on the particular fungus. These diseases may prevent the flowers from blooming properly. Exposure to full sunlight will dry water quickly, reducing the chances of these diseases developing. In severe cases, a dose of spray-on fungicide may help.

  Aphids and spider mites are two sap-sucking insects that can also adversely affect the blooming of chrysanthemums. Severe infestations can even kill mum plantings. If you notice insect activity on your hardy mums, spray them with an insecticidal oil.