Cranberry

Sun

Full sun for the best crop; tolerates light shade but produces fewer berries.

Water

Keep the shallow root zone consistently moist, preferably with rainwater where tap water is alkaline. Avoid prolonged stagnant water around the roots.

Soil

Strongly acidic, moisture-retentive soil with good aeration; aim for pH 4.0-5.5. Use an acidic raised bed or a wide container of ericaceous compost if your garden soil is unsuitable.

Height

0.25-0.5 ft (0.08-0.15 m)

Spread

2-4 ft (0.6-1.2 m), eventually wider where trailing stems root

Flowers

Late spring to early summer; small pale pink flowers with swept-back petals.

Foliage

Evergreen. Small, leathery, dark green leaves with pale undersides; often turn bronze or purplish in winter.

Growth

Slow to moderate; runners gradually form a dense mat.

Care needed

Medium

• Pollinators
• Cold hardy
• Wildlife
• Low allergen
• Edible

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   0.4 ft (0.12 m)

   full size

About 7 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Native to

the US and Canada

In the garden

Spreads vigorously: plan to contain it.

Growth rate

Slow

• Water before the shallow roots dry out, especially while flowers and berries are developing.
• Use rainwater if your tap water is hard; check soil pH if new leaves turn yellow.
• Feed sparingly in spring with a fertilizer for acid-loving plants; excess nitrogen encourages runners at the expense of fruit.
• Apply a light mulch of fine pine bark around new plants, keeping upright shoots uncovered.
• Protect open flowers from late frost with horticultural fleece, removing it during the day so insects can visit.

Pruning. In late winter or early spring, remove dead stems and lightly thin congested, long runners. Keep the short upright shoots, which carry the flowers and fruit; avoid shearing the whole mat.

Pick berries by hand in autumn when they are firm and have developed the mature colour typical of the variety, usually deep red; cut a few open to check that the seeds are brown. Colour alone is not a perfect guide, and ripe cranberries remain very tart. Expect the first worthwhile crop about 3-4 years after planting rooted plants.

Late winter

Remove dead stems and thin excessive runners without cutting away the short fruiting uprights.

Spring

Plant rooted plants in a prepared acidic bed or wide container, and water them in thoroughly.

Spring

Apply a light feed only if growth is weak; check moisture and soil acidity.

Late spring

Protect flowers during forecast frosts and leave them accessible to pollinating insects by day.

Summer

Keep the root zone moist and inspect developing berries for caterpillar damage.

Autumn

Harvest ripe berries by hand and remove damaged or rotten fruit.

Winter

Check containers for drying out and shelter them from drying winds and repeated freeze-thaw cycles.

• Use as an edible groundcover beneath widely spaced blueberries, keeping it out of deep shade.
• Plant along the moist, acidic margin of a bog garden, above any permanently standing water.
• Grow in a broad, shallow container near a path where the flowers and berries can be seen.
• Combine with moisture-loving heaths for a low evergreen carpet with contrasting foliage and flowers.

Garden styles it suits: Bog garden, Edible landscape, Homestead, New England, Wildlife garden and Small-space.

Plant it with: Highbush blueberry, Lingonberry, Bog rosemary and Cross-leaved heath.

Wildlife: Flowers provide pollen and nectar for bees, including bumblebees. Birds and small mammals eat the berries, and the evergreen mat provides low cover.

• Yellow leaves with greener veins usually indicate insufficient acidity or alkaline irrigation water: test the soil, switch to rainwater and correct the growing medium.
• Root rot and dieback can develop in stagnant, poorly aerated soil: improve drainage while maintaining moisture, and remove badly affected plants.
• Cranberry fruitworm caterpillars damage berries in parts of North America: remove infested fruit promptly and clear fallen berries after harvest.
• Poor fruit set can follow flower frost, shade or limited pollinator activity: protect flowers on frosty nights, provide more sun and avoid insecticides during bloom.

Not known to be toxic to people, cats, dogs or horses. The berries are edible, although large quantities can cause digestive upset, particularly in pets; leaves and stems are not normally eaten.

• Small cranberry (Vaccinium oxycoccos)

  Usually has smaller leaves with more strongly rolled-under edges and smaller berries; cranberry has larger, more oblong leaves.

• Lingonberry (Vaccinium vitis-idaea)

  Forms more upright shoots with broader leaves and clusters of bell-shaped flowers, rather than cranberry's trailing stems and swept-back flower petals.

• American highbush cranberry (Viburnum opulus var. americanum)

  An upright deciduous shrub with maple-like leaves, flat clusters of white flowers and bunches of red fruit; it is not a true cranberry.

The species name macrocarpon means 'large-fruited', distinguishing it from smaller-fruited cranberries.

Propagation. Lift and replant rooted sections of runners in spring, or root stem cuttings in a moist, acidic medium. Seed-grown plants are variable and take longer to crop; use vegetative propagation to keep a named variety true to type.

Accepted botanical name

Vaccinium macrocarpon

In the US and Canada

Native in Canada, the lower 48 states and St. Pierre and Miquelon.

Native range

Connecticut, Delaware, District of Columbia, Illinois, Indiana, Maine, Maryland, Masachusettes, Michigan, Minnesota, New Brunswick and New Hampshire.

Measured

Average height 60 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.