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

18"

Habit

Tall, upright, short-lived perennial with rigid unbranched flowering spires

Care tips

•

Expect rust: give plants full sun and good air circulation, avoid overhead watering, and remove infected lower leaves to slow it.

•

Grow against a wall or fence for support and old-world cottage-garden effect; staking is rarely needed except in windy sites.

•

Treat it as a biennial or self-seeder — let some flowers go to seed so new plants carry the planting forward as the short-lived originals decline.

Lifecycle

Planting

Grow in average, medium-moisture, well-drained soil in full sun. Tolerates a wide range of soils and some light shade, but will not tolerate wet winter soils. Provides architectural height for cottage gardens and border backgrounds, and is effective grown against walls or fences (Missouri Botanical Garden PlantFinder).

Transplanting

Has a taproot and resents disturbance; set out young plants while small and avoid moving established specimens. Easiest to start fresh from seed where you want it to grow.

Early growth

Typically biennial: the first season forms a rosette of large, rough, heart-shaped (3-, 5-, or 7-lobed) leaves and the towering spire follows the second year. Watch for rust from the start — it is the plant’s chronic problem.

Maturity

Mature flowering spires reach 5-8 feet and usually do not require staking, though they may need it in windy sites. Spread stays narrow at 1-2 feet. Plants are short-lived but self-seed readily to persist for years (Missouri Botanical Garden PlantFinder).

Propagation

Seed is the standard path. Sow in place or start indoors; many strains flower the second year, while some short-lived-perennial selections bloom the first year if started early. Self-sows freely.

Pollination

Self-fertile

Hollyhock flowers are large, open, and showy and are visited by bees, butterflies, and hummingbirds; Missouri Botanical Garden PlantFinder lists the species as attracting hummingbirds and butterflies. The big mallow flowers offer abundant accessible pollen and nectar, so insect visitation is generous even though no pollinizer partner is required to set the prolific self-sown seed.

Plants don't grow alone

Larval host

Butterfly

Painted lady (Vanessa cardui)

Wisconsin extension and Animal Diversity Web name hollyhock (Alcea, Malvaceae) as a documented Vanessa cardui larval host; caterpillars web the leaves.

Nectar forage

Bird

Ruby-throated hummingbird (Archilochus colubris)

Missouri Botanical Garden PlantFinder lists Alcea rosea as attracting hummingbirds; the large funnel-shaped flowers offer accessible nectar through the June-August bloom.

Pollen forage

Bee

Common eastern bumblebee (Bombus impatiens)

The wide-open mallow flowers present abundant pollen that bumblebees readily work; Missouri Botanical Garden notes the species attracts butterflies and the flowers are broadly insect-visited, though the PlantFinder profile does not name a specific bee species.

For people

Parts edible

Hollyhock is a mallow-family relative of marshmallow; the flowers and young leaves are traditionally used as edible garnishes and in herbal teas, and the flowers are mucilaginous like other mallows. It is grown as an ornamental, not a food crop, and is not a documented toxic plant on the Missouri Botanical Garden PlantFinder profile. Treat culinary use cautiously and only with positive identification.

Native range

AHS heat range

1-11

Climate notes

•

Missouri Botanical Garden PlantFinder lists Alcea rosea for USDA zones 2-10 in full sun with medium moisture, blooming June to August at 5-8 feet tall and 1-2 feet wide; native range is given as "Garden origin" (not a wild North American native).

•

NC State Extension Gardener Plant Toolbox publishes a narrower horticultural range of USDA 5a-9b for Alcea rosea, with the same 5-8 ft height and 1-2 ft spread and full-sun requirement.

•

Both Missouri Botanical Garden PlantFinder and NC State Extension flag the same chronic problem: foliage is highly susceptible to hollyhock rust, plus leaf spot and anthracnose, with spider mites, Japanese beetle, and hollyhock weevil as additional pests. This makes hollyhock a high-maintenance choice (Missouri Botanical Garden lists Maintenance: High).

In the designer

Growth over time

60-96" tall · 12-24" spread

Self-sown seedlings carry the planting forward; the original plant is short-lived.

Design roles: Structure · Focal point · Pollinator

Hollyhock

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