Mums, especially early season varieties, are sensitive to high temperatures during flower initiation. This phenomenon is known as “heat delay.” When short days are provided to initiate flowers, heat delay occurs when temperatures exceed approximately 85 degrees Fahrenheit.Click to see full answer. Consequently, what temperature can mums tolerate? Cold Temperatures In general, mums are hardy in U.S. Department of Agriculture plant hardiness zones 5 through 9, although this can vary slightly by species. According to the USDA map, the lowest minimum temperatures mums can survive are right around 20 degrees below zero Fahrenheit.Beside above, can you plant mums in the summer? Spring or summer – If planted in spring or summer, mums will have ample time to establish a good root system. If the soil is not too wet during the winter, they will overwinter just as other perennials. Mums will do best in raised beds or sandy soil. Similarly one may ask, will mums survive a frost? Frost Protection Mums do not respond well to frosts and freezes, which may not occur until December or January in warmer areas. If you don’t want your mums to suffer damage, you can protect them by moving them to a sheltered area such a garage or porch if they are potted.How long do potted mums last?Garden mums may be grown in containers, or planted in beds with existing shrubs and flowers. Flowers generally last about two or three weeks, depending on the outdoor temperatures and how far along the blooming process was when the plants were purchased.