annualN. America Native

Snow-on-the-Mountain

The Story

Plant Bio

Euphorbia marginata is an erect, warm-season annual native to the North American plains, valued for its striking variegated foliage. The upper leaves and bracts develop clean, bright white margins that surround clusters of small, greenish-yellow flowers from mid-summer until the first hard frost.

The dramatic white coloration intensifies on the newest growth as the plant matures, creating a snowy canopy over medium-green lower foliage. All parts of the plant contain a caustic, milky white latex sap that deters mammalian herbivores but requires careful handling.

Uses & Benefits:

Provides striking, long-lasting white-and-green foliage contrast in sunny borders and mixed annual beds.

The toxic, bitter sap makes the foliage highly unpalatable to deer, rabbits, and other mammalian pests.

Attracts generalist native bees and small pollinating insects to its nectar-producing cyathia.

Essentials

At a Glance

Plant Type

Annual

Height

36"

Width

24"

Light

Full Sun, Partial Sun

Zones

4, 5, 6, 7, 8, 9, 10

Water

Low to Medium

Humidity

Moderate

Lifespan

Annual

Native To

North America

Toxicity

Highly Toxic / Skin Irritant

Bloom period

Mid-summer – Early fall

In flower about 3 months of the year

Planting

How to Grow

Select a site in full sun with sharply-draining, lean soil, avoiding areas with heavy clay or standing water.
Sow seeds directly into the garden after the last spring frost, pressing them lightly into the soil surface without burying them deeply.
Water sparingly once established, allowing the top few inches of soil to dry out completely between waterings.
Wear heavy gloves and long sleeves when handling the plants to avoid skin contact with the irritating milky sap.

Pro Tip

Plant in lean, unamended soil under full sun; excess nitrogen or shade causes the stems to stretch and flop while reducing the crisp white variegation.

Keep It Thriving

Care Guide

Do

Grow in full sun to maintain a compact, upright habit.
Ensure the planting site drains rapidly to prevent root rot.
Pinch young growing tips early in the season to encourage branching.
Wear gloves and eye protection whenever cutting or handling the stems.

Don't

Do not apply high-nitrogen fertilizers, which cause weak, leggy growth and fade the white variegation.
Do not plant in heavy clay or poorly-drained soils.
Do not overwater, as wet roots quickly lead to plant collapse.
Do not handle the plant with bare skin due to the risk of severe contact dermatitis.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Pest Check
Pinch
Plant
Winter Prep

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Cottage GardensAnnual BordersPrairie GardensRock GardensMass Plantings

Companion Plants

Echinacea purpurea Rudbeckia fulgida Salvia nemorosa

Multiply

Propagation Methods

Good to Know

Common Questions

Snow-on-the-Mountain questions

What zones can Snow-on-the-Mountain grow in?

Snow-on-the-Mountain is hardy in USDA Zones 4–10. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Snow-on-the-Mountain deer resistant?

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

When does Snow-on-the-Mountain bloom?

Snow-on-the-Mountain typically blooms in mid-summer through early fall. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Snow-on-the-Mountain need full sun?

Snow-on-the-Mountain does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.

Is Snow-on-the-Mountain drought tolerant?

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