Herb
Stevia
Stevia rebaudiana · Asteraceae
Also called: Sweetleaf, Sweet Herb of Paraguay, Candyleaf, Sugarleaf
Stevia (Stevia rebaudiana) is a moderate-water herb well suited to Tucson and the low desert. It's a moderate-growing herb. Expect white blooms late summer to fall.
Stevia at a glance
- Water use
- Moderate (established)
- Sun
- Full sun in mild months but provide afternoon shade in Tucson's summer—intense low-desert heat and reflected light scorch the foliage and stress transplants.
- Mature size
- 1–2 ft tall and about 18 in wide.
- Growth rate
- Moderate
- Bloom
- White, Late summer to fall (short-day bloomer); small white flowers. Pinch off buds to keep leaves sweet.
- Cold hardiness
- Frost-tender; tender perennial hardy to USDA 9/10–11. Tucson (9a–9b) is borderline—it is often killed or knocked back by winter freezes and is best grown as a warm-season annual or protected/containerized over winter.
- Soil
- Well-drained, loamy soil rich in organic matter; prefers slightly acidic to neutral pH (6.5–7.0). Tucson's alkaline, fast-draining native soil should be heavily amended, or grow in containers/raised beds with quality potting mix.
- Native range
- Subtropical highlands of Paraguay and Brazil.
- Best used as
- Natural calorie-free sweetener (fresh or dried leaves, tea), Container and raised-bed herb gardens, Edible ornamental
- Wildlife
- Late-season flowers offer minor nectar for pollinators.
- Toxicity
- Non-toxic; leaves are a recognized natural sweetener and safe for people and pets.
How to grow Stevia in Tucson & the low desert
Watering
Plant transplants in spring after frost danger passes and nights stay above ~50°F; avoid planting in midsummer heat. Has shallow roots and is not very drought-tolerant—keep soil consistently moist (water 2–3 times weekly in summer) but never waterlogged, which causes root rot.
Fertilizer & nutrients
Light feeder—too much nitrogen reduces leaf sweetness. Amend with compost and use a low-nitrogen, balanced organic fertilizer sparingly during the growing season.
Pruning & care
Pinch tips early and often to promote bushy growth and more leaves. Harvest leaves before flowering for peak sweetness (flowering reduces sweetness); cut plants back after bloom.
Notes
In the low desert, avoid midsummer planting and give afternoon shade to establish spring transplants. Leaves are 30–40x sweeter than sugar—harvest before flowering. Does best in amended raised beds or pots where soil moisture and pH can be managed.
Sources: Growing In The Garden (Phoenix low-desert) – How to Grow and Use Stevia; Missouri Botanical Garden Plant Finder – Stevia rebaudiana; University of Arizona Cooperative Extension herb guidance; Wikipedia: Stevia rebaudiana