When Does Forsythia Normally Bloom in Missouri?

Gardeners throughout the world look to border forsythia (Forsythia x intermedia) to signal that spring has truly arrived. While timing varies from year to year depending on weather, forsythias in Missouri can begin blooming anytime from March through April. In years with very mild winters, it can even be much earlier. In Missouri and elsewhere, many factors influence the timing and quantity of forsythia's flowers.

Forsythia blooms are not brought on by the occasional warm and sunny day. Instead, they coincide with soil temperatures warming to 50 to 55 degrees Fahrenheit. Gardeners watch for the blooms because this is the point when many annual gardening tasks should take place. As soil temperatures rise in early spring, forsythia bursts forth with bright yellow flowers that line its long graceful stems before its leaves arrive. The blooms dominate a landscape still hungry for color. The vibrant, bell-shaped flowers measure up to 1.5 inches in length and last for two to three weeks.

Proper pruning is essential to maximize forsythia's blooms. The early-flowering buds are formed the previous growing season. Pruning is best done immediately after flowering in spring, before the next year's buds develop. An alternative is to prune in late winter, intentionally taking out some upcoming blossoms. Stems can be easily seen then, and cut branches brought inside for forcing in a vase will bloom in about 10 days. Forsythia's branches generally reach 6 to 9 feet or more. Prune this vigorous shrub in keeping with its natural arching habit. A good rule is to take out about one-third of the plant's oldest stems at the base each year. This revitalizes growth and leaves plenty of buds.

For abundant blooms, consider both stem hardiness and bud hardiness when choosing a forsythia shrub for your U.S. Department of Agriculture plant hardiness zone. Frost damage, like improper pruning, translates to a loss of spring blooms. Because buds set prior to winter, choose a variety that is not only stem hardy in your area but bud hardy as well. Otherwise, you'll have a lovely green shrub in spring but very few gorgeous yellow blossoms. Border forsythia is generally both stem hardy and bud hardy throughout Missouri, from USDA zone 5 in the northern-most areas through USDA zone 7 in the state's southeast corner.

Many cultivated varieties extend the range and usefulness of this beautiful herald of spring. Heavy-flowering "Lynwood Gold" forsythia (Forsythia x "Lynwood Gold"), suitable for USDA zones 5 through 8, bears extra-large blooms and purplish fall foliage. "Meadowlark" forsythia (Forsythia x "Meadowlark"), bud hardy to minus 35 degrees, is suitable for USDA zones 3b through 8 and has foliage that takes on reddish fall color. An excellent choice for a groundcover shrub, "Arnold Dwarf" forsythia (Forsythia x "Arnold Dwarf") stays at just 2 to 3 feet in height while spreading to 7 feet. Suitable to USDA zones 5 through 8, it's attractive throughout the year but especially when its yellow blooms signal that spring has arrived.