For many, the deciduous forsythia shrub (Forsythia spp.) provides the first sign of spring. In U.S. Department of Agriculture plant hardiness zones 5a through 10a, the graceful, arching branches, covered with yellow flowers, appear as early as January or February. All forsythias grow best in full sun, in a variety of soil types and with watering every few weeks. They are effective as hedges, espaliered on a fence, in a large garden border or as specimen plants.
A group of hybrid forsythias (Forsythia x intermedia), with flowers ranging from pale to dark yellow, is the one you might be most familiar with. Varieties within this species include large, upright forsythias such as “Beatrix Farrand” and “Spectabillis"; medium-sized shrubs such as 6-foot “Spring Glory” and “”Show Off”; and very small varieties like the 20-inch high “Gold Tide.”
So named because they thrive in cooler climates, hardy hybrids (Forsythia hardy hybrids) retain their buds even in minus 30 degree Fahrenheit temperatures. Varieties that can even be grown in USDA plant hardiness zone 4 include the mounding, 5-foot tall “New Hampshire Gold” and the erect, 8- to 10-foot tall “Northern Sun.”
Growing 1 1/2 to 3 feet tall and 6 feet wide, dwarf forsythia (Forsythia “Arnold Dwarf”) is classified as a creeping groundcover. Its blossoms are far less dense than other forsythias, but it does provide fast-growing erosion control for slopes and stream banks.
Both Korean forsythia (Forsythia ovata) and “Vermont Sun” (Forsythia mandshurica “Vermont Sun”) are erect forms that are early blooming. Weeping forsythia (Forsythia suspensa) is also an erect form but has long, drooping branches that often and easily take root, making it a good choice for erosion control along stream banks. Greenstem forsythia (Forsythia viridissima) grows 6 to 10 feet tall and has stiff branches with greenish-yellow flowers. It also comes as a dwarf form, “Bronxensis,” which reaches only 1 foot tall and 2 to 3 feet wide.
- The New Sunset Western Garden Book; Kathleen Norris Brenzel, ed
- The Garden Primer; Barbara Damrosch
- Jupiterimages/Photos.com/Getty Images