Introducing yellow flowering bushes into your landscape is a great way to add sunny color on gray days. Yellow-flowered bushes--especially those with thorns--can also provide privacy and security as screening hedges. Many of them have the added bonus of fragrant blooms and colorful fruits attractive to birds, butterflies and wildlife. Several varieties of thorny yellow flowering bushes do double duty as garden ornaments and shields.
Whitethorn acacia (Acacia constricta) belongs to the pea family. Reaching between 9 and 15 feet, whitethorn acacia bushes produce fragrant yellow sphere-shaped flowers from May to August, followed by 2- to 4-inch red beans. The narrow pointed leaves often drop off in dry weather, and the bark takes on a purple winter hue. The plant's older branches develop thorns.
Wild Whitethorn acacia grows in the high deserts of Texas, Arizona and New Mexico. It likes full sun and dry sandy or sandy loam soil. Flowers and beans make it a good ornamental addition to gardens; its thorns deter trespassers. The nectar attracts both bees and butterflies. Collect seeds for planting--they will be dark brown--when the bean pods are fully mature or plant it by root division.
Huisache bush (Acacia farnesiana) produces spiny twigs with feathery pale green foliage and fragrant globes of small yellow flowers with multiple protruding stamens. The plant gets its name, says the Lady Bird Johnson Wildlife Center, from a Native American word meaning "many thorns." In Europe the bushes are grown commercially for their flowers, a source of perfume.
Flowers appear between January and April in the United States, where Huisache grows wild along the Gulf, in the southwest, and in California. Huisache bushes need full sun but tolerate a wide range of dry soils including sand, loam and clay. The bushes send out suckers to form thickets, making them useful as privacy screening.
Gorse (ulex europeaus), another thicket-forming bush, is impenetrable due to the 2-inch razor-sharp thorns at the ends of its branches. Gorse, with glossy evergreen leaves, produces masses of yellow pea-like blooms followed by pods that burst and release large amounts of seed. In some climates, says Virginia Tech University, gorse will stay in bloom all year long. Its leaves may turn yellow in the spring, making an even more dramatic display.
While the fragrant showy blooms make it an attractive bush, controlling gorse is a tedious effort. Gorse will invade other plantings, and its high oil content makes the bush a fire hazard. Gorse likes shade and moist, well-drained soil.