Blacknight, Hollyhock Seeds

Blacknight Hollyhock Seed

Near-black maroon flowers create unforgettable vertical drama
Tall perennial spires anchor cottage-garden backgrounds
Single blooms reveal the refined Spotlight Series form
Excellent against pale fences and lighter flowers

See product details

Key Attributes

Botanical Name

Alcea rosea

Days to maturity

90 Days

Sun

Full Sun

Packet

15 Seeds

Zones 2–10 Check your growing zone

About Blacknight, Hollyhock Seed, Hollyhock Seed

Blacknight Hollyhock is a striking, tall-growing perennial known for its deep, almost black, maroon-purple blooms that add dramatic contrast to garden borders and cottage-style landscapes. Part of the renowned "Spotlight Series," this hollyhock variety typically reaches heights of 5 to 6 feet and produces single, saucer-shaped flowers on sturdy, upright stems from mid to late summer. It thrives in full sun and well-drained soil, attracting pollinators like bees and butterflies while also being relatively deer-resistant. Ideal for background planting or along fences and walls, Blacknight Hollyhock combines old-fashioned charm with a bold, modern color.

Growing details

Planting

Sow Depth

1/4"

Days to Germination

10–21 days

Germination Type

B - Warm-Water Soak

In-row plant spacing

18-24"

Plant profile

Life Cycle

Biennial

Plant Height

72 inches

Growth Habits

Clumping, Upright

Seed & variety

Seeds Per Ounce

4,594

Color

Black, Purple

Seed Type

Open Pollinated

Before Planting

Place hollyhocks in full sun with well-drained soil and airflow, preferably where tall flower stalks can remain undisturbed. Weed and loosen the bed, using compost modestly. Prepare a fine surface and soak seed in warm water before sowing to soften the coat.

Planting

Sow hollyhock outdoors in fall or start indoors according to its germination requirement; many perennial species benefit from a cool period before warmth. Maintain even moisture during germination and provide bright light after emergence. Harden indoor-grown seedlings before planting outdoors. Transplant while young to minimize root disturbance, and thin direct sowings after sturdy true leaves develop.

Watering

Water hollyhock regularly until established, then irrigate deeply only when the soil becomes dry. Avoid frequent shallow watering and saturated conditions, which encourage weak growth or root disease.

Fertilizer

Top-dress hollyhock with compost or apply one balanced feeding in spring. Additional fertilizer is rarely needed unless growth is weak or a soil test identifies a deficiency.

Harvesting

Cut hollyhock flowers when blooms are well colored and at the opening stage best suited to display. Harvest during the cool morning with clean shears, leaving healthy foliage for continued flowering.

Tips

Stake tall hollyhock plants before stems lean, using loose ties that allow growth. Pinch branching types when young, deadhead regularly, and leave selected seed heads for wildlife if desired.

Disease Resistance Abbreviations

Rust

Pests & Diseases

Hollyhock rust is the signature disease, producing yellow spots above and orange-brown pustules beneath leaves. Remove the first infected leaves promptly and cut stalks after flowering. Eliminate volunteer mallow hosts, avoid wetting foliage, and begin each season with clean plants rather than saving badly rusted seed stalks.

Aphids and thrips may cluster on hollyhock buds, while mites, Japanese beetles, slugs, and caterpillars feed elsewhere. Remove badly damaged growth, collect visible pests, and choose pollinator-conscious controls only when monitoring shows a need.