Vine
Purple Lilac Vine
Hardenbergia violacea · Fabaceae
Also called: Lilac Vine, Purple Coral Pea, Happy Wanderer, False Sarsaparilla
Purple Lilac Vine (Hardenbergia violacea) is a low-water vine well suited to Tucson and the low desert. It grows to 10-16 ft H x 6-10 ft W (slender twining stems) in full sun to partial shade, with a moderate growth rate.
Purple Lilac Vine at a glance
- Water use
- Low (established)
- Sun
- Full sun to partial shade; in the low desert it performs best with afternoon shade or filtered light and protection from intense reflected heat.
- Mature size
- 10-16 ft H x 6-10 ft W (slender twining stems)
- Growth rate
- Moderate
- Bloom
- Violet-purple, pea-like flowers in pendent sprays (also pink and white cultivars), Winter into early spring (roughly January-March), a valued cool-season bloomer
- Cold hardiness
- Hardy to about 24-25 F (USDA zones 9-11); frost-sensitive at the colder end and may suffer foliage damage in hard freezes.
- Soil
- Needs well-drained soil; tolerates alkaline desert soils but resents soggy conditions. As a legume it fixes some of its own nitrogen.
- Native range
- Australia (eastern and southern Australia)
- Best used as
- Trellis, arbor, and patio post cover, Cool-season color screen, Fence and wall accent, Container vine on supports
- Wildlife
- Pea-like flowers attract bees and other pollinators.
- Toxicity
- No significant toxicity reported; not listed among toxic landscape plants.
How to grow Purple Lilac Vine in Tucson & the low desert
Watering
Water regularly during establishment; once established it is fairly drought-tolerant but looks best with deep irrigation every week or two in summer. Avoid overwatering and poor drainage, which cause root problems.
Fertilizer & nutrients
Low fertilizer needs; being a nitrogen-fixing legume it requires little to no nitrogen. A light feeding after bloom in spring is sufficient; iron may be applied if chlorosis appears in alkaline soil.
Pruning & care
Prune lightly to shape and control after the late-winter/spring bloom finishes; avoid heavy pruning before flowering since blooms form on older wood. Pinch young plants to encourage fullness.
Notes
Evergreen twining vine valued for rare winter-into-spring purple color when little else blooms. Needs sturdy support and appreciates a sheltered microclimate; mass-blooming sprays are a strong seasonal feature. Does best with some heat protection in Tucson.
Sources: AMWUA Landscape Plants for the Arizona Desert; University of Arizona Cooperative Extension; Arizona-Sonora Desert Museum; Tohono Chul / Tucson Botanical Gardens