Connecticut Garden Journal: Forsythia
When I was a boy, my mother would always notice forsythias blooming in spring. I thought she was saying “for Cynthia” when she talked about the plant. I never knew who Cynthia was, and didn't learn the true name of this shrub until I grew up.
Forsythia is often overlooked as a common, messy-looking, deciduous shrub. But there many good reasons to grow it. The flowers make a stunning visual show and they're a great source of pollen for bees and pollinators. The plant can grow large for an excellent privacy hedge. And if it gets out of control, forsythia is easily pruned back severely and will regrow readily. Plus, forsythia blooming is a sign to spread corn gluten organic herbicide on lawns to kill emerging crabgrass.
The key is planting the right variety. For large varieties try 'Northern Sun' and 'Meadowlark'. These grow to 10 feet tall and have hardier flower buds making them good choices for colder areas. 'New Hampshire Gold' grows 4 to 5 feet tall and has red fall foliage color. Forsythia suspensa is a weeping version that can be trained up a trellis. 'Dwarf Arnold' is a dwarf variety that only grows 2 to 3 feet tall. And there's a white forsythia. Abeliophyllum is related to forsythia, but produces white flowers instead of yellow, usually a little earlier than forsythia.
Plant forsythia in full sun on well-drained soil. In cold areas, plant in a protected spot so the flower buds don't get killed from the winter's cold. Prune after flowering but don't prune after July or you'll be removing next year's flower buds.