If you spot hummingbirds hovering around a tree, chances are good the tree has tubular flowers. The narrow blossoms are ideal for the birds' long beaks. Many of these trees are found in the warm climates of the tropics or deserts (USDA Hardiness Zones 7 to 11), and their showy flowers make an attractive addition to your garden.
The Bird-of-Paradise tree (Strelitzia nicolai) is related to the flower Birds-of-Paradise (Strelitz reginale). The tree, found in USDA Hardiness Zones 9b through 11, can reach a height of 15 to 30 feet. Its large, banana-like leaves, which can grow 8 feet long, form a spiral pattern around the trunk. The white and dark-blue tubular flowers bloom year-round and attract hummingbirds. It is a low-maintenance tree that makes an excellent accent in a garden.
Desert Willow Tree
The Desert Willow (Chilopsis linearis) is a slender-twigged tree that produces pink tubular flowers from May until September. According to Las Pilatas Nursery, it is not uncommon to find hummingbirds nesting within this tree. While the Desert Willow was named for its resemblance to the willow tree, it is actually related to catalpa trees, trumpet vine and yellowbells. The tree grows 10 to 14 feet tall and wide in Zones 7 to 9. Give your desert willow full sun and only enough water to keep it from wilting.
The Traveler's Tree (Ravenala madagascariensis) is often mistaken for a palm tree because of its showy, fan-shaped leaves. The banana-like leaves spread across the tree, which grows up to 30 feet high and 20 feet wide in Zones 10 and 11. According to the Oxford Journal, the tubular white flowers of the Traveler's Tree are approximately 2 inches long. The Traveler's Tree prefers full sun and fertile soil; it is a heavy feeder. Use fertilizer made for palms or tropical plants. The Traveler's Tree is somewhat drought tolerant.
The Boojum Tree (Fouquieria columnaris) is limited to desert regions and native to the Sonoran Desert. The Boojum Tree is a bizarre and strange-looking plant that will reach 70 to 80 feet tall. Elizabeth Davison of the University of Arizona Arboretum describes Boojums as being shaped like "snakey naked candles or spiny upside down carrots." Small tubular white flowers appear in spikes up and down the tree. Because it is a succulent, it will need sandy soil and regular watering in cool weather; it is dormant during the warm season. According to the University of Arizona, Boojums are protected and can only be purchased if grown from a nursery in the United States. As of 2010, the asking price for a Boojum tree is $1,000 per foot in height.