Planting Zone 5a: Plants That Grow in USDA Hardiness Zone 5a

USDA hardiness zone 5a covers areas where the coldest winter night averages −20 °F to −15 °F (−28.9 °C to −26.1 °C). 2,393 ZIP codes in 18 states fall in zone 5a, mostly in Iowa, Minnesota, Wisconsin, Vermont and South Dakota. PlantoScan lists 200 plants that survive winter outdoors in zone 5a.

Winter low (°F)
−20 °F to −15 °F
Winter low (°C)
−28.9 °C to −26.1 °C
US ZIP codes
2,393
Hardy plants
200

What Temperatures Define Hardiness Zone 5a?

Hardiness zone 5a is defined by an average annual extreme minimum temperature of −20 °F to −15 °F (−28.9 °C to −26.1 °C). This is the colder half of zone 5, which spans −20 °F to −10 °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 5abenefit 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 4b (−25 °F to −20 °F)Warmer: zone 5b (−15 °F to −10 °F) →

Which States Are in Hardiness Zone 5a?

Zone 5a appears in 18 states of the contiguous US. Iowa, Minnesota, Wisconsin, Vermont and South Dakota have the most ZIP codes in zone 5a, based on the official 2023 USDA ZIP code table.

  • Iowa · 563 ZIPs
  • Minnesota · 271 ZIPs
  • Wisconsin · 250 ZIPs
  • Vermont · 176 ZIPs
  • South Dakota · 168 ZIPs
  • Maine · 151 ZIPs
  • New York · 141 ZIPs
  • Michigan · 132 ZIPs
  • Nebraska · 112 ZIPs
  • Montana · 111 ZIPs
  • Wyoming · 110 ZIPs
  • Colorado · 73 ZIPs
  • New Hampshire · 59 ZIPs
  • Idaho · 41 ZIPs
  • Illinois · 28 ZIPs
  • Utah · 3 ZIPs
  • Nevada · 3 ZIPs
  • New Mexico · 1 ZIPs

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

What Plants Grow in Zone 5a?

200 plants in PlantoScan's catalogue are hardy in zone 5a, meaning zone 5a falls inside their hardiness range. They include 73 trees, 29 shrubs, 46 perennials, herbs & flowers, 12 vines & climbers.

Trees for Zone 5a (73)

Shrubs for Zone 5a (29)

Perennials, Herbs & Flowers for Zone 5a (46)

Vines & Climbers for Zone 5a (12)

Succulents & Cacti for Zone 5a (4)

Grasses for Zone 5a (15)

Ferns for Zone 5a (8)

Other Plants for Zone 5a (13)

Which Popular Plants Aren't Hardy in Zone 5a?

These popular plants need a warmer zone than 5a 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 5a?

Successful zone 5a gardens rely on perennials, shrubs and trees rated to zone 5 or colder. Plants rated right at zone 5a 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 5a — 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.