Balboa Sunset® trumpet vine

Campsis radicans ‘Monbal’

Seed pods of Campsis radicans at USU in August 2025, shown alongside reddish-orange flowers. Photo: S. Burlakoti

Summary

Campsis radicans ‘Monbal’ is a vigorous, woody, deciduous climbing vine in the family Bignoniaceae, derived from a species native to the southeastern United States. The plant has a strong climbing habit and attaches to structures using aerial rootlets, allowing it to rapidly cover trellises, fences, and arbors. Mature vines can reach 30–40 ft in height and spread several feet laterally. The foliage is dark green and pinnately compound, with 7–11 serrated leaflets per leaf, turning yellow in the fall before leaf drop. The plant produces clusters of large, tubular, trumpet-shaped flowers that are deep reddish-orange to scarlet with orange tones. Blooming typically occurs from late spring through early fall and the flowers are highly attractive to hummingbirds and other pollinators. After flowering, the plant produces long, bean-like seed capsules that split open to release winged seeds. This fast-growing vine thrives in full sun and a wide range of soil conditions once established. NC State Extension notes that Balboa Sunset is hardy in USDA Zones 4–10, while Monrovia reports that the cultivar performs well in USDA Zones 4–11. It tolerates drought, heat, and urban conditions. However, it can spread aggressively through suckers and self-seeding, requiring regular pruning to control growth. 

The growth of  Balboa Sunset was vigorous across all irrigation treatments, with plants developing dense foliage and strong climbing stems that rapidly covered the trellis during the growing season. Trellis coverage increased steadily from spring through late summer, with many vines forming a large canopy and providing substantial shade by mid-season. Flowering began in early summer and continued through late fall, with the highest flower density observed during midsummer. The large reddish-orange trumpet-shaped flowers created a striking display and were among the most visually attractive vines in the trial. Plants were highly rated during the 2025 open house evaluations, receiving average appearance ratings of 4.18, 4.30, and 4.32 for the 80%, 50%, and 20% ETo irrigation treatments, respectively. Foliage quality and overall appearance remained consistently high throughout the growing season, and pest or disease issues were minimal.

Survival was excellent, with 100% of plants surviving during both the 2024 and 2025 seasons, indicating high cold tolerance. Vigorous vegetative growth and consistent flowering were observed even in the 20% ETo treatment, suggesting strong drought tolerance. Following flowering, elongated seed pods typical of trumpet vines developed and persisted into the late season. Although plants climbed well on the trellis, some stems tended to grow outward away from the structure, requiring periodic pruning and training to maintain coverage on the trellis.  Balboa Sunset was one of the most highly rated vines during open house evaluations due to its dense foliage and abundant flowering.