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Zone 3a: What Grows and How to Garden There

Zone 3a supports a solid list of hardy fruit, shrubs and perennials: zone 3 apples on standard rootstock, bush cherries, hardy plums, haskaps, currants, lilacs, rugosa roses, peonies and lilies. The limits are winter cold on anything rated zone 4 or warmer, and a short summer that favors early vegetable varieties and warmed soil.

Coldest winter night
-40 to -35°F
ZIP codes in the zone
23
Typical last frost
May 26
Typical first frost
September 14
Frost-free season
About 114 days

Frost dates in zone 3a

Hardiness zones measure winter cold, so places in one zone can have quite different springs. Across zone 3a, the typical last frost ranges from about May 10 to June 2, and the first fall frost from September 12 to October 1 (the earliest and latest tenth of ZIP codes). For a typical place in the zone:

  • May 10Risky: a later frost happens in 9 years out of 10
  • May 26Typical last frost
  • June 11Safe: a later frost only 1 year in 10

What a zone 3a winter means

In zone 3a, the plant tag matters more than anything else you do. Choose perennials, shrubs and fruit rated to zone 3 or colder, and treat zone 4 plants as experiments for your most sheltered spot. Snow is the other key: NDSU Extension recorded soil 12 inches down at 31°F while the air was 4°F, because snow traps ground heat. Early, deep snow protects roots and bulbs; a snowless cold snap is what kills plants. In an open winter, shovel snow over low shrubs and perennials.

Where zone 3a is

Zone 3a ZIP codes are in two places. In Alaska they include Fairbanks itself, Delta Junction and other interior communities. In the Lower 48 the zone touches northern Minnesota, in the cold lake and forest country of the Arrowhead and the Rainy River region around Tower.

Fruit trees and small fruit

  • Apples: NDSU lists apples hardy to zone 3, including ‘Dakota Gold’, ‘Norkent’, ‘State Fair’, ‘Hazen’, ‘Duchess’, ‘Wealthy’, ‘Goodland’, ‘Red Baron’, ‘Haralson’ and ‘Wodarz’; ‘Honeycrisp’ and ‘Zestar!’ are marginal in zone 3. In Alaska, UAF recommends ‘Trailman’, ‘Schafer’, ‘Alma Sweet’ and the Prairie series. Standard-size trees only, on hardy rootstock.
  • Cherries: Montana State found the University of Saskatchewan dwarf sour cherries hardy to zone 3 in its trials, ripening from late July (‘Carmine Jewel’) into August.
  • Plums: SDSU rates ‘Underwood’, ‘Black Ice’, ‘LaCrescent’ and ‘Toka’ very hardy; hybrid plums need two cultivars, and ‘Toka’ is an excellent pollinator.
  • Berries: haskaps, currants, gooseberries and summer-bearing raspberries.

Perennials, bulbs and shrubs

NDSU rates common lilac and rugosa rose hardy to zone 2, and Pekin lilac to zone 3. Peonies thrive and, in Fairbanks, bloom in July and August. Hardy lilies come through winter under snow. Daylilies, hostas and Siberian iris are long-lived choices.

Short-season vegetables

Grow varieties with short days to maturity, start tomatoes and peppers indoors (Montana State allows 6-10 weeks to transplant size), and warm the soil with plastic mulch. Peas, lettuce, beets, carrots, kale, broccoli and onions are frost-tolerant and the most dependable crops.

What to plant each month in zone 3a

For a typical place in the zone. Your own dates may be a couple of weeks earlier or later; enter your ZIP code to see them.

  1. February

    Start indoors: onions

  2. March

    Start indoors: black-eyed susans, broccoli, cabbages, cauliflower, chives, collard greens, ginger, kale, leeks, lettuce, marigolds, onions, oregano, parsley, peppers, petunias, ranunculus, rosemary, sage, snapdragons

  3. April

    Start indoors: basil, black-eyed susans, cabbages, cauliflower, celery, chives, cilantro, collard greens, eggplants, ginger, lettuce, marigolds, nasturtiums, peppers, ranunculus, sage, snapdragons, spinach, swiss chard, tomatoes, zinnias

    Plant or sow outdoors: beets, black-eyed susans, blackberries, blueberries, broccoli, cauliflower, chives, cilantro, collard greens, figs, garlic, gladioli, grapes, grass seed, hollyhocks, kale, leeks, onions, peas, poppies, radishes, ranunculus, raspberries, rhubarb, roses, spinach, strawberries, swiss chard, turnips, wildflowers

  4. May

    Start indoors: basil, cantaloupes, cosmos, cucumbers, okra, pumpkins, ranunculus, watermelons, winter squash, zinnias, zucchini

    Plant or sow outdoors: asparagus, beets, black-eyed susans, blackberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, collard greens, dahlias, dill, figs, garden mums, gladioli, grapes, green onions, kentucky bluegrass, lavenders, leeks, lettuce, lilies, marigolds, mints, nasturtiums, onions, oregano, parsley, perennial ryegrass, petunias, potatoes, radishes, ranunculus, rosemary, roses, sage, snapdragons, spinach, sunflowers, sweet corn, sweet peas, swiss chard, tall fescue, thyme, turnips, zinnias

  5. June

    Start indoors: cosmos, okra

    Plant or sow outdoors: asparagus, basil, cantaloupes, chives, cilantro, cucumbers, dahlias, dill, eggplants, garden mums, ginger, gladioli, grapes, green beans, green onions, kentucky bluegrass, lavenders, lettuce, lilies, marigolds, mints, nasturtiums, oregano, parsley, peppers, perennial ryegrass, petunias, pumpkins, ranunculus, rosemary, sage, spinach, st. augustinegrass, sunflowers, sweet corn, sweet peas, swiss chard, tall fescue, thyme, tomatoes, watermelons, winter squash, zinnias, zucchini

    Plant for fall: bearded irises, broccoli, brussels sprouts, carrots, collard greens, lettuce, peas, snapdragons, swiss chard

  6. July

    Plant or sow outdoors: bermudagrass, celery, centipedegrass, cosmos, green onions, okra, peanuts, st. augustinegrass, sweet potatoes, zoysiagrass

    Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, carrots, cauliflower, clematis, collard greens, coneflowers, daylilies, hostas, hydrangeas, kale, lettuce, peas, radishes, roses, saffron, snapdragons, spinach, swiss chard, turnips

  7. August

    Plant or sow outdoors: bermudagrass, centipedegrass, st. augustinegrass, zoysiagrass

    Plant for fall: azaleas, bearded irises, cabbages, cauliflower, clematis, coneflowers, crocuses, daffodils, daylilies, grass seed, hostas, hyacinths, hydrangeas, kale, lilies, ornamental alliums, peonies, radishes, roses, saffron, spinach, tulips

  8. September

    Plant for fall: crocuses, daffodils, garlic, hyacinths, lilies, ornamental alliums, peonies, tulips

Planting schedules for zone 3a

Where zone 3a is

States with zone 3a ZIP codes, the largest first: Alaska, Minnesota.

Zone 2bZone 3bAll zones and the zone finder

Questions

Can I grow dwarf apple trees in zone 3a?

Not reliably. NDSU Extension says dwarfing rootstocks are not hardy in zone 3 and recommends standard-size trees on hardy rootstocks such as Dolgo or Antonovka. In Alaska, apples are grafted onto very hardy crabapple rootstock.

Which perennials live longest in zone 3a?

Iowa State lists peony, daylily, hosta, Siberian iris, daffodil, baptisia and sedum among perennials that often last 20 years or more. Peonies are especially long-lived; Iowa State notes 50- to 60-year-old plants are not unusual.

How do I get warm-season vegetables to ripen in zone 3a?

Pick early, short-season varieties, start them indoors, and warm the soil with clear or black plastic mulch and row covers. Montana State's rule is simple: if a crop's days to maturity exceed your frost-free days and it cannot take frost, it probably will not mature.