Shrub · Ericaceae
Cranberry
Vaccinium macrocarpon
Offer it acidic peat, full sun, and steady moisture, and this low creeping vine will thank you with tart berries come fall.
Full sun
Every 2–4 days
USDA 3–7
4–8 in · 10–20 cm
Overview
The cranberry is a low, creeping evergreen vine that calls the cool bogs and wetlands of northern North America home. It sits in the heath family beside blueberries and lingonberries, and like them it longs for the kind of very acidic, peaty ground that would leave most garden plants struggling. As the vines spread, they root along the way, staying only a few inches high while reaching wide.
What makes a cranberry special is just how particular it likes things, and that is nothing to be afraid of. The bed should stay evenly moist yet drained, the soil should sit close to pH 4.0 to 5.5, and the plant needs full sun to set a good crop. Pink and white blooms arrive in late spring, and the familiar red berries color up through fall. Once it settles in it is hardy and long-lived, so a little patience early on is well rewarded.
Think of this as a plant for one devoted corner rather than a crowded border, and you will do just fine. Give it a contained bog bed or a damp, acidic patch where its runners can wander, keep the lawn and vegetables at a safe distance, and a cranberry planting can fruit for decades.
Care
The short version: full sun, steady even moisture, and acidic peaty soil near pH 4.0 to 5.5. Keep the feeding light, let the runners have room to roam, and rake out the extra in early spring.
Light
Cranberries crop best in full sun, with 6 or more hours each day. They will get by in partial shade, but a shaded bed tends to run to leafy runners and hand you only a handful of berries.
Water
Aim to keep the bed in constant, even moisture, watering around every 2 to 4 days so it never dries out. The companion trick is drainage: the roots love damp peat but not a standing pond, so make sure the water has a way to move on.
Soil
Set the plant in acidic, organically rich peat and sand kept consistently moist but well-drained. Aim for a pH of 4.0 to 5.5, well below what most plants can handle, which is exactly why cranberries do best in a bed all their own.
Temperature
This is a wonderfully cold-hardy plant, content from -40°F to 86°F (-40°C to 30°C). Harsh winters won't trouble it at all; it is summer heat past that upper mark, not the cold, that finally tests its limits.
Humidity
A middle-of-the-road 40% to 70% humidity suits cranberries nicely. What matters more than any precise figure is steady airflow through the bed, since stagnant, damp growth is what tends to invite fruit rot.
Feeding
Feed gently from spring through early summer with a food made for acid-loving plants. Cranberries prefer low fertility, so a light hand is best: too much nitrogen builds runners and leaves while holding back the fruit.
Pruning
There is very little pruning to do here. Rake or mow out the extra trailing runners in early spring to steer the plant toward upright fruiting shoots and to keep air flowing through the bed.
Repotting
A bog-container planting seldom asks for repotting. Refresh the acidic media every 2 to 3 years, and let roots circling the pot or runners crowding the surface tell you when the time has come.
Size & spacing
The vines keep low, only 4 to 8 inches (10 to 20 cm) tall, yet they reach 1 to 6 feet (30 to 180 cm) across. Plan for that wandering habit and give each plant the space to mat out across the bed.
When to plant
Cranberries follow the northern seasons and feel at home in USDA zones 3 to 7. Plant rooted cuttings or vine pieces out in spring as soon as the soil can be worked, look forward to pink and white flowers in late spring, and pick the ripe red berries from early fall.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Set rooted cuttings or vine pieces out in spring once the soil can be worked (April to May).
- Harvest: Blooms May to June with pink and white flowers; fruit ripens and is harvested September to November.
Hardiness
USDA hardiness zones: 3–7
Temperature: down to -40°C
Troubleshooting
Nearly every cranberry hiccup comes down to one of two things: soil that has slipped out of the acidic range, or a bed that sits too wet and still. The reassuring part is that the leaves and berries tell you early, so you can usually set things right before the planting really suffers. Find what matches your plant below, then step in while it still does the most good.
Leaves shifting to yellow or red between the veins
Take heart, this is chlorosis, and it is very fixable. When the soil creeps above roughly pH 5.5, iron gets locked away from the roots and the color fades. Start by testing the bed so you know where you stand, then nudge it back down with elemental sulfur or a fresh top-up of acidic peat. Switching to non-alkaline water and a feed made for acid-loving plants will help the green return.
Fix:
- Acidify soil with elemental sulfur or amend with acidic peat
- Irrigate with non-alkaline water
- Apply a fertilizer formulated for acid-loving plants
Berries turning soft, sunken, or spoiled
When a bed stays warm, wet, and short on drainage, fungal fruit rot can move in and leave the berries mushy and off-colored. Don't worry, you can turn this around: gather up and discard every affected berry, then loosen things up with better drainage and more air moving through the vines. Keep a registered fungicide in mind only for the times when the rot is outpacing you.
Fix:
- Improve drainage and air circulation
- Remove and discard infected fruit
- Apply a registered fungicide per label if severe
Plenty of vine and leaf, but barely any fruit
A bed thick with trailing runners and few upright shoots is usually a sign of too much shade or too much nitrogen steering growth away from fruit. The good news is the cure is simple. Give it full sun and lighten up on the feeding, and rake or trim the surplus runners back in early spring to coax the plant toward the upright shoots that hold the berries.
Fix:
- Site in full sun
- Reduce nitrogen fertilization
- Rake or prune excess runners in early spring
Toxicity
Here is some lovely news: the cranberry is non-toxic from root to berry. The fruit is a kitchen favorite, and the extract is even fed to cats and dogs to support urinary health. The most a curious pet risks is a mild stomach upset from gobbling too many at once.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
You can relax around cats, since cranberry is safe for them and the berry even shows up in feline urinary supplements. The most that might happen is a passing tummy upset if one helps itself to a whole pile of fruit.
Dogs None
Dogs are welcome to share cranberries, and the extract is given to them on purpose for urinary health. The only thing to watch for is a soft stool or a little gas after a big helping.
Horses Safe
Horses grazing nearby have nothing to fear from the low vines or the tart berries.
Rabbits Safe
Rabbits can safely nibble both leaves and fruit, with the berries best offered now and then as a treat rather than every day.
Livestock Safe
Cattle, goats, and sheep are perfectly fine around cranberry plants and their fruit.
Birds Safe
Wild birds feast on ripe cranberries and carry the seeds along, all without any risk to them.
People Safe
People enjoy cranberries cooked, dried, or pressed into juice, and they are a holiday staple. Eaten raw they are simply very tart, never harmful.
No special handling needed; the plant is non-toxic, though eating large amounts of fruit may cause mild digestive upset.
Varieties
Just a few cultivars bring in most of the cranberry harvest, chosen for color, yield, and how well the berries keep. These are the names worth getting to know.
Stevens
A high-yielding, disease-resistant hybrid that has grown into the most widely planted commercial choice.
Ben Lear
An early-ripening variety valued for its rich color and used widely as breeding stock.
Howes
A Massachusetts heirloom whose firm berries are known for storing and keeping unusually well.
Companions
Plant near
Lowbush blueberry (Vaccinium angustifolium): Shares the same very acidic, peaty, moist soil and growing conditions.
Lingonberry (Vaccinium vitis-idaea): Another acid-loving evergreen groundcover with matching soil and moisture needs.
Keep apart
Lawn grasses and most vegetables: They need near-neutral soil and cannot tolerate the very acidic, wet conditions cranberries require.
How to propagate
Cranberries are almost always begun from cuttings or by layering, and both methods copy a known cultivar for you. Seed is possible but slow and a touch unpredictable, so few growers take that path.
Stem cuttingsModerate
Spring to early summer · Roots in a few weeks; 3 to 5 years to a full fruiting bed
This is the route commercial growers rely on, and you can follow it too. From spring through early summer, press 6 to 10 inch vine cuttings into damp acidic peat and sand and keep them consistently moist. Roots appear within a few weeks, and while it takes 3 to 5 years for the bed to fill in and fruit well, the wait pays off.
LayeringEasy
Spring to summer · One growing season to root
This one practically does itself. The trailing runners root wherever they touch moist soil, so simply pin a runner down in spring or summer and let it settle into a new plant over a single growing season.
SeedDemanding
After cold stratification in late winter · Several years
Seed is the long, uncertain road, so most growers skip it. The seed needs cold stratification in late winter before it will sprout, the seedlings creep along for several years, and they won't match the parent cultivar.
Myths
Cranberries grow underwater in flooded bogs.
Cranberries actually grow on low trailing vines set in moist, well-drained acidic peat, not beneath water. Growers flood the beds only for short stretches, to float the harvest and to shelter the vines over winter. Through the growing season the soil stays drained, never sitting underwater.
Cranberry berries are toxic to dogs and cats.
Plain cranberries are gentle and non-toxic to pets, and the extract is even sold as a pet urinary supplement. A large helping might bring on a mild stomach upset, but that holds true for nearly any fruit.