The Yellow Bell Flower (Allamanda cathartica), also well known as the Golden Trumpet Vine or Buttercup Flower, is a fast-growing evergreen shrubby vine commonly enjoyed for its bright, bell- or trumpet-shaped blooms. It can be trained to grow on a trellis, a tree trunk, or another vertical support, or it can be maintained as a shrub. As a tropical vine, it is typically grown as an annual or wintered indoors in climates that experience freezing temperatures. It is rated for outdoor growth as a perennial in USDA Hardiness Zones 9b to 11.
The Yellow Bell Flower features large, glossy, medium-green leaves that reach to four or six inches in length. This foliage creates a fine background for the plant’s bright, lush, prolific blooms, which endure from spring deep into fall in warmer climates. Note that several cultivars are available featuring a variety of flower colors besides yellow.
The Yellow Bell Flower is propagated by seeds and vegetative cuttings. Seeds are readily available and potted plants can be purchased ready for planting in your garden.
The Yellow Bell Flower climbs with a twining growth habit, meaning it twists itself around a vertical structure to gain height. If you plan to use the plant as a climbing vine, you may need to attach it to the chosen structure until it has a firm hold.
For best flowering results, plant the Yellow Bell Flower in full sun. It does do quite well in light shade environments, however. The plant flourishes in a quick draining, rich, loamy soil, though it is adaptable to virtually all soils except those that are highly alkaline.
Prune annually for size. As indicated above, this plant can be pruned for growth as a shrub rather than a climbing vine. Use gloves when cutting the plant’s stems, as the Yellow Bell Flower’s sticky white sap is poisonous.