perennial

False Spirea

Astilbe simplicifolia 'Key Largo'

The Story

Plant Bio

Astilbe simplicifolia is a clump-forming herbaceous perennial native to the woodlands of Japan, valued for its glossy, deeply divided foliage and feathery flowering plumes. The species thrives in cool, shaded environments where consistent moisture is available, producing airy panicles of flowers that rise above the compact foliage mound in summer.

'Key Largo' is a compact cultivar distinguished by its bright raspberry-pink to shell-pink flower plumes borne on contrasting red stems. The finely dissected, glossy kelly green leaves emerge bright green in spring and darken as they age, maintaining a refined texture throughout the growing season.

Uses & Benefits:

Produces feathery, raspberry-pink plumes over glossy, finely dissected foliage on contrasting red stems.

Highly resistant to browsing by deer and rabbits, making it ideal for woodland borders.

Attracts bees, butterflies, and other generalist pollinators to shaded garden areas.

Essentials

At a Glance

Plant Type

Perennial

Height

18"

Width

15"

Light

Partial Sun, Shade

Zones

4, 5, 6, 7, 8, 9

Water

High

Humidity

Moderate to High

Lifespan

Perennial

Native To

East Asia (Japan)

Toxicity

Non-toxic

Bloom period

Mid summer – Late summer

In flower about 2 months of the year

Planting

How to Grow

Select a site in partial to full shade with humus-rich, organically rich, and well-drained soil.
Plant the crown just below the soil surface, ensuring it is not buried too deeply to prevent rot.
Apply a thick layer of organic mulch around the base to retain consistent moisture and keep roots cool.
Water regularly to ensure the soil remains evenly moist and never dries out completely.

Pro Tip

Mulch the root zone heavily with organic compost to preserve soil moisture; a single instance of the soil drying out completely during summer will cause irreversible leaf scorch and margin browning.

Keep It Thriving

Care Guide

Do

Maintain consistent soil moisture throughout the hot summer months.
Mulch annually with organic compost to enrich the soil and retain moisture.
Cut back dead foliage to the ground in early spring before new growth emerges.

Don't

Do not allow the soil to dry out, even briefly, during dry or hot spells.
Do not bury the sensitive crown too deeply when planting or mulching.
Do not prune into old, leafless wood mid-season.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Divide
Fertilize
Mulch
Pest Check
Spring Cleanup

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Shade GardensBorder EdgingWoodland GardensMass PlantingsRain Gardens

Companion Plants

HostaFerns Heuchera Carex

Multiply

Propagation Methods

Good to Know

Common Questions

False Spirea questions

What zones can False Spirea grow in?

False Spirea is hardy in USDA Zones 4–9. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is False Spirea deer resistant?

Yes — False Spirea is rated deer-resistant. Deer typically pass it over, though extreme hunger can override any plant's defenses.

When does False Spirea bloom?

False Spirea typically blooms in mid summer through late summer. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does False Spirea need full sun?

False Spirea does best in part shade.