A very popular hybrid Bougainvillea, 'Barbara Karst' is a free-flowering, vigorous, evergreen shrub or vine with particularly eye-catching clusters of bright red to magenta-red, papery bracts surrounding tiny white flowers. Blooming periodically throughout the year in warm winter areas, and from summer to fall elsewhere, the colorful blossoms give way to small inconspicuous fruits, 1/2 in. long (1 cm). The flowers are borne on stems clad with short thorns and dull, wavy-edged, ovate green leaves. They do not cling and may require tying for support.

• Fast-growing, this Bougainvillea can be of variable size, depending on how it is maintained and the support provided. If left unpruned, it could get as high as 25-40 ft. (7.5-12 m) and as wide as 5 to 40 ft. (1.5-12 m).
• Thrives in full sun or light shade, in acid, well-drained soils. Bougainvillea tolerates hot, dry locations fairly well, but dislikes constantly wet soils. Good drought tolerance once established but will look better if watered during dry spells. Water freely in summer and sparingly in the winter. Fertilize every two weeks during the growing season.
• Excellent choice for mass plantings, as specimen plants, wall-side borders, groundcovers for banks, in rock gardens, and containers. Can also be espaliered or trained on a standard or grown in a large basket.
• Deer resistant with a good salt spray tolerance. While it can be grown near the shore, some light protection should be provided.
• Regular pruning may be required to keep inbounds or shape the plant. Always prune this plant immediately after flowering. Be aware that repetitive pruning may reduce flowering as this plant flowers on new growth. Pinching the tips of new growth will encourage branching.
• Cuttings 4-6 in. long (10-15 cm), put under mist, will usually root in 4 to 6 weeks.