Hardenbergia violacea
The prodigious flower display on the lone Hardenbergia 'Happy Wanderer' in February 2026 after a year and a half of deficit irrigation at UC Davis. Photo: JA Sisneroz
Summary
While often known as the Lilac Vine, Hardenbergia violacea is a vigorous evergreen native to the landscapes of Australia. It is hardy in USDA zones 9-11. This vine’s structure is composed of many thin wire-like vines, with a tendency to grow a little sporadically when not trained. Once established on a structure, these vines get entangled with each other, forming excellent dense foliage cover throughout the year. The foliage consists of leathery, deep f was a consistent performer across the deficit trial. This species est-green leaves with a long, narrow, elliptical shape that tapers down towards the end. From late Winter to early Spring they extrude in clusters of small, vivid purple flowers. Each individual bloom has a unique, almost orchid-like shape that provides a sharp visual contrast against the foliage. While this vine may be temperamental during its initial establishment, it becomes a solid and hardy landscape piece once settled in.
South Coast REC Results & Discussion
The Lilac vine, while visually stunning in a few individuals, experienced establishment issues that led to high variation and significant mortality during this trial. As a result, a little less than half of the vines were remaining by the end of the trial. Nearly all of the plants that died were rated as unacceptable starting from the time of their establishment and up until their deaths. The vines that had poor establishment displayed sparse, narrow leaves and woody core branches.
Of the plants that did survive, the large majority remained at or above an acceptable appearance. They tended to cover a large portion or the entirety of the trellis. Some individuals also sprawled outwards and resembled a large bush or wall of green. These plants remained relatively constant throughout the second year of the trial. There was a blooming period that lasted throughout spring and into early summer. When blooming, the vines created a vibrant wall of violet flowers, attracting many pollinators that included swarms of bees. In fact, the buzz of bees swarming the vine could be heard when approaching the plant. The blooming season for these vines ended around early summer. Only a small portion of individuals retained an even smaller portion of flowers during the 2025 Summer Open House. They still retained an acceptable appearance throughout the season. Furthermore, they continued to vigorously push new growth, eventually expanding outwards from the trellis. There was no sign of yellowing in the leaves, and by the time of the 2025 Fall Open House, participants rated these vines as a very acceptable vine, although not quite a model vine.
Basic Info
| Submitted by: | |
| Site(s): | UC Davis & SCREC |
| Trial Exposure: | Sun |
| Year evaluated: | 2025 |
| Height & Width after 2 years: | |
| Reported Height & Width at maturity: | |
| WUCOLS plant type: | S V |
| Water Needs & WUCOLS Region: | N/A - Region 2 Low - Region 3 |
| Mean Overall Appearance rating (1-5 Scale, 5 is highest) | SCREC - 3.7 |
| Flowering Months: |
Growth and Quality Data
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Hardenbergia violacea at SCREC in October 2025, under the low water treatment with full coverage and dense foliage. Photo: N Lo
Hardenbergia ‘Happy Wanderer’ at UC Davis. Photo: JA Sisneroz
Hardenbergia ‘Happy Wanderer’ at UC Davis in the mid-day sun. Photo: JA Sisneroz