Great Design Plant: Sandpaper Verbena (Glandularia rigida) — Purple Ground Cover

Flowering ground covers paint low garden areas in color. Drought-tolerant sandpaper verbena (Glandularia rigida) delivers vibrant deep purple from spring through fall, attracting butterflies. Beyond needing good drainage, this South American native is unfussy about soil and thrives in full sun — handling 100°F+ down to 0°F. It excels in drier climates where water limits its spread.

Caution: Avoid in hot, humid climates (Florida, Southeast) where it can become invasive.

Botanical name: Glandularia rigida (syn. Verbena rigida)
Common names: Sandpaper verbena, rough verbena, tuberous vervain
Origin: Southern Brazil and Argentina
Zones: 7 (hardy to 0°F)
Water: Drought-tolerant once established; best with deep watering twice monthly in summer, every 3 weeks in spring/fall, monthly in winter (no rain); low desert: weekly in summer, biweekly in spring/fall
Light: Full sun
Size: 1–2 ft tall, 3–4 ft wide
Benefits: Drought-tolerant; attracts bees and butterflies
Seasonal interest: Flowers spring, summer, fall
When to plant: Spring or fall from seed or transplants

Distinguishing Traits

Clusters of deep purple flowers on stiff stems over dark green, sandpaper-textured leaves (2–4 in long). Deciduous in winter but regrows rapidly from rhizomes in spring. Handles cold to 0°F; mulch helps in sub-freezing temps. Not recommended for warm, humid Southeast where it's naturalized. Popular in arid Western landscapes.

Shown: Sandpaper verbena along a dry river bed with Mexican evening primrose (Oenothera mexicana), fernleaf lavender (Lavandula multifida), germander sage (Salvia chamaedryoides).

Deep purple flowers are a highlight: clusters of 3–5 one-inch blooms spring through fall on rigid stems. Bees and butterflies love them. Prune to ground in early spring; new growth follows. Severe pruning 1–2 times in summer controls size and boosts flowering and fresh foliage.

How to Use It

Plant along winding paths or by large boulders to showcase color and upright stems. Suitable for slopes — summer carpet of purple. Thrives in street medians with limited soil and reflected heat.

For cool palettes: pair with moss verbena (Glandularia pulchella), blackfoot daisy (Melampodium leucanthum), bush morning glory (Convolvulus cneorum), Parry's penstemon (Penstemon parryi).

For texture/color contrast: plant beside large boulders and blue-gray common sotol (Dasylirion wheeleri).

For bold color contrast: combine with angelita daisy (Tetraneuris acaulis), golden barrel cactus (Echinocactus grusonii), firecracker penstemon (Penstemon eatonii), Mexican honeysuckle (Justicia spicigera).

As understory: plant before taller shrubs — Blue Bells (Eremophila hygrophana 'Blue Bells'), Cape honeysuckle (Tecomaria capensis), little-leaf cordia (Cordia parvifolia), red bird-of-paradise (Caesalpinia pulcherrima), yellow bells (Tecoma stans) — for color contrast with their flowers.

Shown: Sandpaper verbena alongside lamb's ear (Stachys byzantina 'Big Ears'), purple Tapien verbena (Verbena Tapien hybrids), orange 'Hallmark' bulbine (Bulbine frutescens 'Hallmark').

Planting Notes

Not fussy: full sun, well-drained soil. Reseeds itself. Prune to ground as needed in spring/summer to rejuvenate.

Shown: Sandpaper verbena next to artichoke agave (Agave parryi var. truncata).

Browse plants native to other U.S. regions.