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

USDA hardiness zone 4b covers areas where the coldest winter night averages −25 °F to −20 °F (−31.7 °C to −28.9 °C). 1,256 ZIP codes in 14 states fall in zone 4b, mostly in Minnesota, Wisconsin, South Dakota, Montana and New York. PlantoScan lists 154 plants that survive winter outdoors in zone 4b.

Winter low (°F)
−25 °F to −20 °F
Winter low (°C)
−31.7 °C to −28.9 °C
US ZIP codes
1,256
Hardy plants
154

What Temperatures Define Hardiness Zone 4b?

Hardiness zone 4b is defined by an average annual extreme minimum temperature of −25 °F to −20 °F (−31.7 °C to −28.9 °C). This is the warmer 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 4bbenefit 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 4a (−30 °F to −25 °F)Warmer: zone 5a (−20 °F to −15 °F) →

Which States Are in Hardiness Zone 4b?

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

  • Minnesota · 344 ZIPs
  • Wisconsin · 238 ZIPs
  • South Dakota · 183 ZIPs
  • Montana · 129 ZIPs
  • New York · 107 ZIPs
  • Vermont · 70 ZIPs
  • Wyoming · 43 ZIPs
  • Michigan · 38 ZIPs
  • North Dakota · 35 ZIPs
  • Maine · 30 ZIPs
  • Iowa · 17 ZIPs
  • New Hampshire · 10 ZIPs
  • Colorado · 10 ZIPs
  • Idaho · 2 ZIPs

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

What Plants Grow in Zone 4b?

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

Trees for Zone 4b (48)

Shrubs for Zone 4b (21)

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

Vines & Climbers for Zone 4b (9)

Succulents & Cacti for Zone 4b (4)

Grasses for Zone 4b (9)

Ferns for Zone 4b (8)

Other Plants for Zone 4b (13)

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

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

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