Florida gardening: Queen's wreath, a lovely vine for Treasure Coast
Q: I have a lovely tree with lovely lavender flowers. I live in Hobe Sound and have not been able to identify the tree. Thank you for your help.
— Cecilia, Hobe Sound
A: What an intriguing way to plant a queen's wreath. Your tree is actually a vine that has been cultivated as standard. A horticultural standard is a plant that has been trained to have a single stem resembling a tree with a trunk and leaves and flowers at the top.
Petrea volubilis — known as queen's wreath, purple wreath and sandpaper vine — is classified as a sprawling shrub or liana in the Verbena family.
The definition of liana varies by source. Merriam-Webster says, "any of various usually woody vines, especially tropical rain forests that root in the ground." Others report that lianas use rainforest trees for support, often hanging from trees. I think of them as woody vines, which describe petrea very well.
Queen's wreath is a twining vine with elliptical to oval, large leaves, 5 to 9 inches long. It is primarily evergreen, though some individuals have been known to lose their leaves infrequently.
They are rough and stiff, like sandpaper and opposite on the stems. Petrea is native to Southern Mexico, Central America, northern South America, and the Caribbean.
Petrea is sometimes known as tropical wisteria. It is reminiscent of the prevalent and, in some locations, invasive wisteria found in more northern climates. This vine has spectacular lavender/purple blooms in drooping 8 to 12-inch clusters.
The star-shaped flowers consist of tubular bluish flowers nestled inside the more showy and persistent purple calyces (the outside covering of the flower). When the flower's petals fall, the long-lasting purple calyx stays behind, extending the bloom.
The heaviest flowering occurs in the spring, but a new flush of flowers may occasionally appear throughout the year. When the true flowers are present, they are attractive to bees, hummingbirds and butterflies.
Use queen's wreath vine on arbors, fences, and trellis or as an espalier in full sun and shade, though the bloom is better in the sun or light, shifting shade. This vine climbs by twining rather than clinging, so it does not damage walls.
It is moderately salt and wind tolerant and highly drought-tolerant but not cold tolerant. Petrea will take a bit of frost, but temperatures in the 20s will damage or kill the vine. Adaptable to any well-draining soil, petrea is remarkably tolerant to South Florida's alkaline conditions.
The beautiful blossoms can be difficult to clip and use in flower arrangements. The blooms will soon wilt and fade if part of the woody vine is cut with the flower stalk. However, cut only the flower sprays and display them in a bowl or vase, and the arrangement will remain fresh for days.
Petrea is difficult to propagate by seed. It rarely sets seeds, but when it does, it may take several months for the seeds to germinate. Best propagation is by layers or cuttings.
Queen's wreath is a beautiful vine for the landscape or container. It is a delightful choice as a gift for a friend or family member who is missing the abundant blooms of the spring-time temperate gardens.
Carol Cloud Bailey is a landscape counselor and horticulturist. Send questions to carol@yard-doc.com or visit www.yard-doc.com for more information.