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

Well-suited

2050

Zone 7a

Plotwright

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

Well-suited

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.

✓

Well-suited today and still thriving 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 45 ecoregions — 45 climate-resilient through 2070. Best matches first.

Appalachian mixed mesophytic forests

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Appalachian-Blue Ridge forests

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Arizona Mountains forests

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Atlantic coastal pine barrens

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Blue Mountains forests

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California coastal sage and chaparral

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Canadian Aspen forests and parklands

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Central Pacific Northwest coastal forests

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Central Tallgrass prairie

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Central-Southern Cascades Forests

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What it needs

Conditions

Light

Full sun

Water

Moderate water

Spacing

9"

Habit

Bushy upright branching warm-season annual

Care tips

•

Direct-sow after the last frost and re-sow every 2-3 weeks through June for bloom that never quits until frost.

•

Give full sun, space for airflow, and water at the base — powdery mildew is the one reliable zinnia problem.

•

Cut or deadhead often; zinnias are cut-and-come-again, and removing spent heads keeps new flowers coming.

Lifecycle

Planting

Sow seed directly in the ground in full sun after the last frost date, in humusy, evenly moist, well-drained soil. Sow at 2-3 week intervals through the end of June for season-long bloom (Missouri Botanical Garden PlantFinder).

Transplanting

Zinnias resent root disturbance; if started indoors, transplant young hardened-off seedlings carefully before they become root-bound. Direct sowing is generally more successful.

Early growth

Keep soil evenly moist while seedlings establish. Pinch the growing tip on young plants to encourage bushier branching and more flowering stems. Provide good air circulation to limit powdery mildew.

Maturity

Plants reach 1-3 feet (occasionally to 4 feet) and bloom continuously from June to frost. Deadhead or cut flowers regularly to keep new blooms coming; watering at the base rather than overhead reduces foliar disease.

Propagation

Grown from seed, sown directly after frost. As an annual it completes its life cycle in one season; seed can be saved from open-pollinated plants, though many garden zinnias are hybrids that will not come true.

Pollination

Self-fertile

Zinnia flower heads carry both ray and disc florets and are insect-pollinated; Missouri Botanical Garden PlantFinder lists the showy flowers as attracting butterflies and hummingbirds. A single plant can set seed, and zinnias are widely grown without any special pollinizer requirement, though insect visitation improves seed set.

Plants don't grow alone

Nectar forage

Butterfly

Painted lady (Vanessa cardui)

UW-Madison Horticulture lists zinnias among adult Vanessa cardui nectar flowers.

Nectar forage

Butterfly

Red admiral (Vanessa atalanta)

Nectar forage

Butterfly

Monarch butterfly (Danaus plexippus)

Zinnias are a well-documented nectar source for butterflies; Missouri Botanical Garden PlantFinder lists Zinnia elegans as attracting butterflies, and the flat, open, late-season flower heads are a favored monarch nectar plant.

Nectar forage

Bird

Ruby-throated hummingbird (Archilochus colubris)

Missouri Botanical Garden PlantFinder lists Zinnia elegans as attracting hummingbirds; the bright, showy flowers are a common ruby-throated hummingbird nectar source in summer gardens.

Nectar forage

Bee

European honeybee (Apis mellifera)

NC State Extension documents Zinnia elegans attracting bees and pollinators; honey bees forage the disc florets for nectar and pollen across the long summer-to-frost bloom.

Nectar forage

Butterfly

Skipper butterflies (Hesperiidae (family-level entry))

Skippers are frequent visitors to open composite flowers like zinnias; while the species pages cite butterflies generally rather than skippers by name, skipper nectaring on zinnias is widely observed.

For people

Not eaten by humans

Grown strictly as an ornamental and cutting flower — for mixed borders, beds, cottage and cutting gardens, and containers (Missouri Botanical Garden PlantFinder). Not a food crop; no part is grown for eating.

Native range

AHS heat range

6-12

Climate notes

•

Missouri Botanical Garden PlantFinder lists Zinnia elegans as an annual hardy in USDA zones 2-11, grown in full sun with medium water in humusy, evenly moist, well-drained soil; height 1-4 feet and spread 0.75-1 foot, blooming June to frost. As a frost-tender annual it is grown across that full zone range for a single warm season rather than overwintered.

•

PlantFinder notes the showy flowers attract birds, hummingbirds, and butterflies, and that the plant tolerates black walnut. NC State Extension separately documents Zinnia elegans attracting butterflies, hummingbirds, bees, and pollinators.

•

PlantFinder flags susceptibility to powdery mildew, leaf spots, root rots, blight, and Botrytis, and to Japanese beetles. Powdery mildew is the most common problem; good spacing, full sun, and base watering reduce it.

In the designer

Growth over time

5-19" tall · 4-5" spread

Seedling-to-juvenile stage 3-6 weeks after direct sowing; first true leaves and branching begin.

Design roles: Border · Filler · Pollinator · Container

Common zinnia

At a glance

Related products

Why it matters

Cold hardiness

Heat tolerance

Where this plant fits

What it needs

Lifecycle

Pollination

Plants don't grow alone

For people

Native range

Climate notes

In the designer

Sources & citations