Photo: Photo by Keith Weller — Public domain · source
Survives zone 2 through 7
Harvest calendar
Best planted in early spring after your last frost, or in fall before the ground freezes, depending on your climate.
The commercial cranberry — tart, firm, red berries grown on sandy, highly acidic bogs and almost always eaten cooked or processed rather than raw. Bogs are flooded for harvest and frost protection, not because the plant is aquatic.
- Hardiness
- Zone 2–7
- Habit
- Groundcover
- Edible part
- Fruit
- Ripens
- July–Sept
- Mature size
- Trailing evergreen vine 10–20 cm tall with runners to 2 m, rooting as it goes; excellent in containers
- Light
- Full sun
- Soil pH
- 4.0–4.5 — the tightest, most acidic range in the genus; cultivated bogs are commonly run at pH 4–5
- Environment
- Bog
- Native range
- Newfoundland and Labrador west to Saskatchewan and Ontario, south to Minnesota, Michigan and North Carolina; the commercial heartland is the northeastern US (Massachusetts, New Jersey, Wisconsin) and Atlantic Canada (Quebec, Nova Scotia, New Brunswick, PEI).
- Status
- Cultivated
- Years to fruit
- 4–7 yrs to full bog production (runners cover the ground in year one, fruiting uprights form in year two)
- Growth speed
- Moderate — upright shoots elongate roughly 5–10 cm a year depending on cultivar.
- Spacing
- 61 cm (24 in) apart — about 2.7 per m² (2.5 per 10 sq ft)
- Leaf shape
- Small (under 2.5 cm), glossy, leathery ovate leaves with whitish undersides; bronze in spring, green through summer.
- Root system
- Shallow and spreading — creeping surface stems root into the soil; a true bog plant needing constantly moist to waterlogged, acidic peat or sand.
- Fruit description
- Round, glossy red berries about 1–2 cm across with firm flesh containing small internal air pockets (why the fruit floats); very tart, rarely eaten raw.
- Propagation
- New commercial bogs are established from mowed cuttings of an existing bog's vines, pressed into the sand surface — runners cover the ground by the end of the first season, with upright fruiting shoots forming in year two. Home plantings use softwood or hardwood cuttings the same way; seed is used mainly for breeding.
- Pollination
- Self-fertile, better with a 2nd cultivar
The edible parts listed above are a starting point, not a field guide. Identify a plant with certainty — ideally against a local authority — before eating any part of it, and read the full disclaimer. Spotted something wrong? Report it.
Growing guide
Fertilizing. Prefers ammonium-form nitrogen like the rest of the genus, but over-fertilizing is a specific documented risk here: excess feeding drives rank vine growth that worsens the fruit-rot disease complex.
How it spreads. A low trailing evergreen vine, not an upright shrub — long runners creep and root at the nodes, with short vertical "uprights" rising from runner buds to carry the flowers and fruit.
Growing tips. Roots lack root hairs entirely and depend on ericoid mycorrhizal fungi for nutrient uptake in nutrient-poor, sandy bog soil — a well-documented relationship for this species. Needs substantial winter chilling (roughly 1,000–2,500 hours between 32–45°F) to flower and fruit the following spring. Commercial growers typically rent honeybee or bumblebee colonies, since hermaphrodite flowers don't self-pollinate reliably enough for full commercial yield. Watch for cranberry false blossom disease (an incurable leafhopper-spread phytoplasma — infected vines must be removed) and cranberry or Sparganothis fruitworm.
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