Species

Clethra alnifoliaSummersweet

4 other cultivars

shrubN. America Native

Caleb Summersweet

Clethra alnifolia 'Caleb'

The Story

Plant Bio

Clethra alnifolia, commonly known as summersweet, is a deciduous native shrub prized for its fragrant summer flowers that bloom even in shady locations. It typically has attractive yellow fall color.

'Caleb' (marketed as Vanilla Spice) is distinguished by its exceptionally large, pure white flower spikes, which can be twice the size of the species. The fragrance is intensely sweet and spicy.

Uses & Benefits:

The large, fragrant white flower spikes are a highlight of the mid-summer garden, especially valuable for blooming in shady areas. The glossy green leaves turn a beautiful golden-yellow in the fall, extending its seasonal interest.

Its tolerance for wet soils and shade makes it an excellent problem-solver for difficult garden spots. It is also highly deer resistant. The flowers are excellent for cutting.

Clethra is a magnet for pollinators. It provides a crucial mid-summer nectar source for a wide variety of native bees, butterflies, and hummingbirds when many other plants have finished blooming.

SpeciesClethra alnifoliaSummersweet

Essentials

At a Glance

Plant Type

Shrub

Height

60 inches

Width

60 inches

Light

Full Sun, Partial Sun, Shade

Zones

4, 5, 6, 7, 8, 9

Water

High

Humidity

High

Lifespan

Long-lived

Native To

Eastern North America (species)

Toxicity

Non-toxic

Bloom period

Mid-summer – Late summer

In flower about 2 months of the year

Planting

How to Grow

Select a site with moist, acidic soil in sun or shade.
Amend soil with compost or peat moss to increase acidity and moisture retention.
Dig a hole twice the width of the root ball.
Place the plant in the hole, backfill, and water well.
It flowers on new wood, so prune in early spring if needed.
Mulch with pine straw or shredded leaves to maintain soil moisture.

Pro Tip

Plant near a patio or window where its delightful summer fragrance can be fully appreciated.

Keep It Thriving

Care Guide

Do

Provide consistently moist soil.
Mulch well to keep roots cool and moist.
Prune in early spring before new growth begins to shape the plant.
Plant in groups for a stunning floral and fragrant display.

Don't

Don't let the soil dry out, especially in summer.
Avoid planting in alkaline soils, which causes yellowing leaves.
Don't prune after new growth starts, as this will remove flower buds.
Avoid heavy fertilization.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Fertilize
Mulch
Plant
Prune

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Fragrant shrub for shady bordersEssential for pollinator gardensNaturalistic woodland plantings

Companion Plants

Itea virginica Fothergilla gardenii Rhododendron viscosum Osmunda cinnamomea Lobelia cardinalis

Multiply

Propagation Methods

Good to Know

Common Questions

Caleb Summersweet questions

What zones can Caleb Summersweet grow in?

Caleb Summersweet 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 Caleb Summersweet deer resistant?

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

When does Caleb Summersweet bloom?

Caleb Summersweet 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 Caleb Summersweet need full sun?

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