Ageratum 'Blue Hawaii 5.0'

Ageratum houstonianum ‘Blue Hawaii 5.0’ is a compact, blue-flowered annual for low borders and containers. [University of Illinois Extension](https://web.extension.illinois.edu/hortanswers/plantdetail.cfm?PlantID=1&PlantTypeID=1) lists ‘Blue Hawaii 5.0’ at 6–12 inches tall; [UW–Madison Extension](https://hort.extension.wisc.edu/articles/ageratum/) describes ageratum flowering from late spring into fall in frost-free weather. ## Garden use and season Use it along bed edges, in mixed containers, or as a low mass of blue among warmer-colored annuals. Its small, rounded mound suits the front of a planting, while the fuzzy flower heads and green foliage make a soft contrast with fine-textured or upright companions, as described in [UW–Madison Extension’s ageratum guide](https://hort.extension.wisc.edu/articles/ageratum/). ## Growing conditions Give plants full sun or partial shade and moist, well-drained soil. Ageratum is frost tender and is generally grown as a warm-season annual; the exact length of bloom depends on local temperatures and planting date. ## Maintenance Keep the root zone evenly supplied with moisture while plants establish, then water when the soil begins to dry. Remove faded flower heads when they look untidy; deadheading can prolong flowering on varieties that hold old blooms. Protect plants from frost if extending the display into autumn.