perennial

Biennial Hollyhock

Alcea biennis

The Story

Plant Bio

Alcea biennis is a towering, rigid biennial forming a low-lying basal rosette of dusty, sage-green leaves in its first year before shooting a massive, unbranched flowering spike in its second. The foliage is covered in soft, velvety, star-shaped hairs, and the plant establishes a deep taproot to support its upright growth.

This species is distinguished by its soft grey-green to bright green new growth and its long, terminal flower spikes that carry solitary or clustered blossoms in gentle shades of pink, pale lavender, or creamy white. The flowers feature a prominent central column of yellow stamens that attract a wide range of native pollinators.

Uses & Benefits:

Provides dramatic vertical structure and soft pastel blooms perfect for the back of cottage garden borders.

Functions as a reliable self-seeding biennial that naturalizes easily in dry, well-drained soils.

Attracts and supports native bees, butterflies, and hummingbirds with its nectar-rich blossoms.

Essentials

At a Glance

Plant Type

Perennial

Height

80"

Width

36"

Light

Full Sun, Partial Sun

Zones

4, 5, 6, 7, 8

Water

Moderate

Humidity

Moderate

Lifespan

Biennial

Native To

Europe

Toxicity

Skin Irritant

Bloom period

Summer – Fall

In flower about 6 months of the year

Planting

How to Grow

Select a planting site in full sun with neutral to alkaline, well-draining soil.
Sow seeds in late summer or early fall to establish a strong basal rosette before winter.
Space plants 18 to 36 inches apart to allow adequate air circulation and reduce fungal disease risk.
Water regularly during the first growing season to establish the deep taproot, then reduce watering.

Pro Tip

Plant this biennial at the back of borders against fences or walls to shield the heavy, towering stalks from summer winds and avoid the need for manual staking. Ensure the soil is exceptionally well-drained and calcium-rich, as wet winter soils will cause the taproot to rot.

Keep It Thriving

Care Guide

Do

Clear away dead stalks annually at the end of the season to maintain garden hygiene.
Plant in highly permeable soil to prevent winter root rot.
Wear gloves when handling the foliage to avoid skin irritation from the bristly hairs.

Don't

Do not apply high-nitrogen fertilizers, which stimulate soft foliage that is highly susceptible to rust.
Do not water overhead; wet leaves encourage the spread of fungal pathogens.
Do not plant in low-lying, wet areas of the garden where water pools.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Deadhead
Fertilize
Pest Check
Prune
Winter Prep

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Back of BorderCottage GardenCut Flower GardenWildlife Garden

Companion Plants

Echinacea purpurea Salvia Nepeta Rudbeckia

Multiply

Propagation Methods

Good to Know

Common Questions

Biennial Hollyhock questions

What zones can Biennial Hollyhock grow in?

Biennial Hollyhock is hardy in USDA Zones 4–8. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Biennial Hollyhock deer resistant?

Not reliably. Deer may browse Biennial Hollyhock, especially tender spring growth — plan on repellents or fencing where pressure is high.

When does Biennial Hollyhock bloom?

Biennial Hollyhock typically blooms in summer through fall. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Biennial Hollyhock need full sun?

Biennial Hollyhock does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.

Is Biennial Hollyhock drought tolerant?

Yes — once established (usually after the first full season), Biennial Hollyhock handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.