Planting Zone 4a: Plants That Grow in USDA Hardiness Zone 4a

USDA hardiness zone 4a covers areas where the coldest winter night averages −30 °F to −25 °F (−34.4 °C to −31.7 °C). 783 ZIP codes in 14 states fall in zone 4a, mostly in North Dakota, Minnesota, Wisconsin, Montana and New York. PlantoScan lists 154 plants that survive winter outdoors in zone 4a.

Winter low (°F)
−30 °F to −25 °F
Winter low (°C)
−34.4 °C to −31.7 °C
US ZIP codes
783
Hardy plants
154

What Temperatures Define Hardiness Zone 4a?

Hardiness zone 4a is defined by an average annual extreme minimum temperature of −30 °F to −25 °F (−34.4 °C to −31.7 °C). This is the colder half of zone 4, which spans −30 °F to −20 °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 4abenefit 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 3b (−35 °F to −30 °F)Warmer: zone 4b (−25 °F to −20 °F) →

Which States Are in Hardiness Zone 4a?

Zone 4a appears in 14 states of the contiguous US. North Dakota, Minnesota, Wisconsin, Montana and New York have the most ZIP codes in zone 4a, based on the official 2023 USDA ZIP code table.

  • North Dakota · 316 ZIPs
  • Minnesota · 200 ZIPs
  • Wisconsin · 73 ZIPs
  • Montana · 71 ZIPs
  • New York · 29 ZIPs
  • Maine · 26 ZIPs
  • South Dakota · 24 ZIPs
  • Michigan · 13 ZIPs
  • Vermont · 11 ZIPs
  • Wyoming · 10 ZIPs
  • New Hampshire · 5 ZIPs
  • Colorado · 2 ZIPs
  • Idaho · 2 ZIPs
  • Utah · 1 ZIPs

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

What Plants Grow in Zone 4a?

154 plants in PlantoScan's catalogue are hardy in zone 4a, meaning zone 4a falls inside their hardiness range. They include 48 trees, 21 shrubs, 42 perennials, herbs & flowers, 9 vines & climbers.

Trees for Zone 4a (48)

Shrubs for Zone 4a (21)

Perennials, Herbs & Flowers for Zone 4a (42)

Vines & Climbers for Zone 4a (9)

Succulents & Cacti for Zone 4a (4)

Grasses for Zone 4a (9)

Ferns for Zone 4a (8)

Other Plants for Zone 4a (13)

Which Popular Plants Aren't Hardy in Zone 4a?

These popular plants need a warmer zone than 4a 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 4a?

Successful zone 4a gardens rely on perennials, shrubs and trees rated to zone 4 or colder. Plants rated right at zone 4a 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 4a — 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.