Planting Zone 3a: Plants That Grow in USDA Hardiness Zone 3a

USDA hardiness zone 3a covers areas where the coldest winter night averages −40 °F to −35 °F (−40 °C to −37.2 °C). 5 ZIP codes in 1 state fall in zone 3a, mostly in Minnesota. PlantoScan lists 103 plants that survive winter outdoors in zone 3a.

Winter low (°F)
−40 °F to −35 °F
Winter low (°C)
−40 °C to −37.2 °C
US ZIP codes
5
Hardy plants
103

What Temperatures Define Hardiness Zone 3a?

Hardiness zone 3a is defined by an average annual extreme minimum temperature of −40 °F to −35 °F (−40 °C to −37.2 °C). This is the colder half of zone 3, which spans −40 °F to −30 °F in total.

The value is a 30-year average of each winter's single coldest night, taken from 1991–2020 weather records for the 2023 USDA map. Individual winters regularly run a few degrees colder, so plants rated exactly to zone 3abenefit from mulch and a sheltered spot. Gardeners who don't know their zone yet can look up their USDA hardiness zone by ZIP code before comparing plants.

← Colder: zone 2b (−45 °F to −40 °F)Warmer: zone 3b (−35 °F to −30 °F) →

Which States Are in Hardiness Zone 3a?

Zone 3a appears in 1 state of the contiguous US. Minnesota has the most ZIP codes in zone 3a, based on the official 2023 USDA ZIP code table.

  • Minnesota · 5 ZIPs

Hardiness zones follow elevation and water, not state lines, so most states span several zones.

What Plants Grow in Zone 3a?

103 plants in PlantoScan's catalogue are hardy in zone 3a, meaning zone 3a falls inside their hardiness range. They include 28 trees, 12 shrubs, 30 perennials, herbs & flowers, 7 vines & climbers.

Trees for Zone 3a (28)

Shrubs for Zone 3a (12)

Perennials, Herbs & Flowers for Zone 3a (30)

Vines & Climbers for Zone 3a (7)

Succulents & Cacti for Zone 3a (3)

Grasses for Zone 3a (6)

Ferns for Zone 3a (8)

Other Plants for Zone 3a (9)

Which Popular Plants Aren't Hardy in Zone 3a?

These popular plants need a warmer zone than 3a to survive winter outdoors. Grow them as houseplants, in containers that move indoors before the first frost, or as annuals replanted each spring.

How Do You Garden Successfully in Zone 3a?

Successful zone 3a gardens rely on perennials, shrubs and trees rated to zone 3 or colder. Plants rated right at zone 3a survive typical winters but benefit from mulch, windbreaks and a spot near a warm wall.

A hardiness zone describes winter cold only. Planting dates follow your local last spring frost and first fall frost, which differ by weeks within zone 3a — a last frost date calculator by ZIP code gives the dates for your garden. Summer heat, rainfall and soil drainage decide whether a hardy plant thrives. Microclimates matter as well: raised beds, slopes and paved areas warm up faster, while low ground collects cold air on still nights.

Zone temperatures and ZIP codes: 2023 USDA Plant Hardiness Zone Map, USDA Agricultural Research Service and the PRISM Climate Group, Oregon State University. Plant hardiness ranges come from PlantoScan's plant database and are estimates — local conditions, cultivars and winter protection change what survives.