Cold hardiness

Future

2050

2100

These values are location-based: this location's current hardiness is the baseline, and the 2050 value is a projected future climate for this same location.

Now

Zone 6b

USDA

Published baseline for this location from 1991-2020.

Source: USDA Plant Hardiness Zone Map 2023 (1991-2020 climatology) via ArcGIS FeatureServer

Won't grow here

2050

Zone 7a

Plotwright

Projected zone for this same location in 2050 (2041-2070) using SSP3-7.0 (regional rivalry).

Won't grow here

In plain terms: This location is in Zone 6b today. Its hardiness profile is cold winters, and coldest nights are typically around -3°F. By 2050, the projected hardiness zone is Zone 7a based on SSP3-7.0 (regional rivalry). That is a +0.5-zone shift from Zone 6b to Zone 7a by 2050.

✕

Out of range today and still out of range in 2050.

Heat tolerance

Future

2050

2100

Heat tolerance values are location-based too: heat days today are observed at this site, and the 2050 value projects this same location under a future climate.

Loading AHS heat-zone data for this location...

Where this plant fits

Suitable across 17 ecoregions — 11 climate-resilient through 2070 · 6 newly possible by 2070. Best matches first.

Atlantic coastal pine barrens

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California coastal sage and chaparral

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Central Pacific Northwest coastal forests

Eastern Australian temperate forests

New Zealand North Island temperate forests

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Northern Pacific Alaskan coastal forests

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What it needs

Conditions

Light

Full sun / Part sun / Part shade

Water

Moderate water

Spacing

18"

Habit

Tender perennial herb with weak, floppy stems, grown as an annual in most climates

Care tips

•

Use rich, consistently moist but well-drained soil — well drainage matters to prevent root rot.

•

Snip off flower buds as they appear; the sweetest, best-quality leaves form before the plant flowers.

•

Harvest leaves in fall and dry them; dried leaves can be ground into stevia powder in a blender.

Lifecycle

Planting

Grow in rich, consistently moist but well-drained soil in full sun (tolerates part shade). In St. Louis it is grown as an annual: set out starter plants after the last spring frost, or start seed indoors and transplant out once the soil has warmed. Well-draining soil is important to avoid root rot (Missouri Botanical Garden PlantFinder).

Transplanting

Transplant starter plants or indoor-grown seedlings into the garden after the danger of frost has passed and the soil has warmed; plants may also be grown in pots set out on patios during the growing season (Missouri Botanical Garden PlantFinder).

Early growth

Keep the soil consistently moist (medium water) in a rich, well-drained mix; the stems are weak and floppy, so a sheltered spot or light support helps. Pinch growing tips to encourage branching for more leaves.

Maturity

Snip off flower buds as they appear — the best-quality leaves occur prior to flowering — and harvest leaves in fall. Dried leaves can be ground in a blender into stevia powder (Missouri Botanical Garden PlantFinder).

Propagation

Grown from starter plants or from seed started indoors; tender stems can also be rooted from cuttings. It is winter hardy only in zones 10-11, so most gardeners replant each year or overwinter plants indoors.

Pollination

Self-incompatible

Stevia rebaudiana bears small, showy white tubular flowers in July and August; the species is largely self-incompatible and insect-pollinated. Pollination is irrelevant to the leaf harvest, however, because the best-quality leaves occur prior to flowering, so growers snip off flower buds as they appear (Missouri Botanical Garden PlantFinder).

For people

Edible

Grown for its sweet-tasting leaves, which contain glucoside compounds; the dried leaves may be ground in a blender into stevia powder used as a no-calorie sweetener. The best-quality leaves occur prior to flowering (Missouri Botanical Garden PlantFinder).

Native range

AHS heat range

6-12

Climate notes

•

Missouri Botanical Garden PlantFinder lists Stevia rebaudiana for USDA hardiness zones 10 to 11, grown in full sun to part shade with medium water in rich, consistently moist, well-drained soil; height and spread 1 to 2 feet, with white flowers July to August.

•

A tender perennial native to Brazil and Paraguay: it survives winter only in zones 10-11, so across most of North America (including St. Louis) it is grown as an annual or overwintered indoors (Missouri Botanical Garden PlantFinder).

•

MBG notes well-draining soil is important to prevent root rot and that there are no serious insect or disease problems; plants can be grown in pots set out on patios during the growing season and brought in over winter.

In the designer

Growth over time

12-24" tall · 12-24" spread

Survives as a perennial only in zones 10-11 (or when overwintered indoors); elsewhere it is replaced each season as an annual.

Design roles: Edible · Container · Pollinator

Stevia

At a glance

Why it matters

Cold hardiness

Heat tolerance

Where this plant fits

What it needs

Lifecycle

Pollination

For people

Native range

Climate notes

In the designer

Sources & citations