Cold hardiness

Future

2050

2100

These values are location-based: this location's current hardiness is the baseline, and the 2050 value is a projected future climate for this same location.

Now

Zone 6b

USDA

Published baseline for this location from 1991-2020.

Source: USDA Plant Hardiness Zone Map 2023 (1991-2020 climatology) via ArcGIS FeatureServer

Won't grow here

2050

Zone 7a

Plotwright

Projected zone for this same location in 2050 (2041-2070) using SSP3-7.0 (regional rivalry).

Won't grow here

In plain terms: This location is in Zone 6b today. Its hardiness profile is cold winters, and coldest nights are typically around -3°F. By 2050, the projected hardiness zone is Zone 7a based on SSP3-7.0 (regional rivalry). That is a +0.5-zone shift from Zone 6b to Zone 7a by 2050.

✕

Out of range today and still out of range in 2050.

Heat tolerance

Future

2050

2100

Heat tolerance values are location-based too: heat days today are observed at this site, and the 2050 value projects this same location under a future climate.

Loading AHS heat-zone data for this location...

Where this plant fits

Suitable across 32 ecoregions — 22 climate-resilient through 2070 · 10 newly possible by 2070. Best matches first.

Arizona Mountains forests

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Atlantic coastal pine barrens

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California coastal sage and chaparral

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Central Pacific Northwest coastal forests

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Central-Southern Cascades Forests

Eastern Australian temperate forests

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Eastern Great Lakes lowland forests

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Edwards Plateau savanna

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What it needs

Conditions

Light

Full sun

Water

Low water

Spacing

12"

Habit

Bushy upright-mounding aromatic sub-shrub

Care tips

•

Prioritize drainage — sweet marjoram rots in saturated soil far more readily than it suffers from heat or drought.

•

Outside zones 9-10, treat it as a warm-season annual or a pot herb brought indoors before frost; it rarely overwinters reliably.

•

Harvest stems before the flowers open, when leaf flavor peaks, and cut back to keep the plant bushy.

Lifecycle

Planting

Tender perennial hardy only to USDA zones 9-10; grown as an annual elsewhere. Start seed indoors 6-8 weeks before the last spring frost, or sow outdoors about two weeks before last frost. Plant in full sun in average, dry-to-medium, well-drained soil at neutral-to-alkaline pH (Missouri Botanical Garden PlantFinder).

Transplanting

Set hardened-off starts out after frost danger passes; container plants can be brought indoors in fall before frost, though they usually do not overwinter well.

Early growth

Superior soil drainage is the key to growing this plant well (Missouri Botanical Garden) — it will rot in poorly drained, saturated soils (NC State Extension). Keep moisture moderate; the plant has good heat and drought tolerance once established.

Maturity

Mature plants form an upright mound 1-2 feet tall and wide with tiny white-to-pale-pink flowers in July-August. Leaf flavor is usually best before the flowers bloom, so harvest stems ahead of bloom and cut to encourage bushiness.

Propagation

Seed is the standard path; the species also propagates from stem cuttings and division. Refresh woody, declining plants periodically.

Pollination

Self-fertile

Self-fertile like other mints (Lamiaceae) — a single plant sets seed without a partner, and most culinary growers harvest the foliage before bloom anyway. When allowed to flower it provides late-season nectar for bees (NC State Extension), so it earns modest pollinator value even though it does not depend on pollinators to reproduce.

Plants don't grow alone

Nectar forage

Bee

European honeybee (Apis mellifera)

NC State Extension documents that flowering marjoram provides late-season nectar for bees and lists the plant as attracting bees.

Nectar forage

Bee

Common eastern bumblebee (Bombus impatiens)

Open Lamiaceae flowers of the marjoram/oregano group are commonly worked by bumblebees; plausible by analogy to the documented honeybee use, not separately cited for this species.

For people

Edible

A classic culinary herb — the sweet, milder, more floral cousin of oregano. Leaves and flowers are used fresh or dried in soups, stews, dressings, sauces, and teas (NC State Extension); flavor is best harvested before the flowers open (Missouri Botanical Garden).

Edible parts

leaves, flowers

Culinary use

Soups, stews, salad dressings, and sauces; leaves and flowers in herbal tea. Sweeter and more delicate than oregano — add late in cooking to preserve the volatile aroma. Best harvested before bloom when leaf flavor peaks.

Pet toxicity

NC State Extension flags Origanum majorana as a problem for cats and dogs; essential-oil-rich mints can cause gastrointestinal upset in pets on ingestion.

Native range

AHS heat range

6-12

Climate notes

•

Missouri Botanical Garden PlantFinder lists Origanum majorana as a tender perennial winter-hardy to USDA Zones 9 to 10, grown as an annual elsewhere, in full sun with dry-to-medium water and neutral-to-alkaline soil. NC State Extension states the same range at finer granularity: USDA hardiness zones 9a, 9b, 10a, 10b.

•

Heat and drought tolerant (Missouri Botanical Garden); NC State Extension lists tolerance/resistance to deer, drought, dry soil, heat, poor soil, and rabbits, and notes the plant is intolerant of poorly drained, saturated soils where it rots.

•

Tolerates warm to extreme summer heat — a Mediterranean culinary herb with documented heat + drought tolerance; thrives in hot, dry summers and is most reliable as a true perennial only in the warm zones 9-10 where it survives winter.

In the designer

Growth over time

8-24" tall · 12-24" spread

Mature mound; replace woody, less-productive plants from fresh seed or cuttings.

Design roles: Edible · Container · Border

Sweet marjoram

At a glance

Why it matters

Cold hardiness

Heat tolerance

Where this plant fits

What it needs

Lifecycle

Pollination

Plants don't grow alone

For people

Native range

Climate notes

In the designer

Sources & citations