Large Cranberry

Size, growth and what to expect

It grows at a medium pace for its size, a few inches a year in our growth estimator. It makes a mat under a foot tall, with upright shoots about 2 to 8 inches high, and one plant spreads 2 to 3 feet. The small, glossy leaves are bronze in spring, green in summer and coppery to purple in fall.

Pink to white flowers nod on slender stalks from May into July, each with four swept-back petals around a beak of stamens. The berries ripen in September and October, red, round and a third to half an inch across, and they can hang on into winter. They make good sauce, jam and muffins. Bees carry the pollen, and birds eat some berries.

It grows wild from Newfoundland and Quebec west to Minnesota, south to Illinois, Indiana, Ohio and Virginia, and in mountain bogs to North Carolina and Tennessee. Its home is bogs, fens, swamps, marshes and wet shores. It needs about three months of cool winter weather and does poorly in heat and drought. It is grown on the Pacific coast too, and it has escaped there.

How to grow Large Cranberry

Large cranberry grows in full sun or light shade, and the more sun it gets, the more it fruits. It needs an acid soil, about pH 4 to 5.5, that stays moist but drains, such as sand, peat or a mix of the two. Alkaline soil or limy water yellows the leaves. Standing water for more than about two weeks starves the roots, though it takes brief flooding. Set plants 2 feet apart and keep them 2 feet from a wall. At its size it can go within 15 feet of overhead wires.

Saplings ship potted. The roots are tender and the plant is hard to move, so plant it from the pot in spring, before hot weather, and keep the root ball whole. Set the crown at the soil line, firm the soil around it, and spread a thin layer of sand between the runners. The seed is small and needs light to sprout. Keep the damp seed in the refrigerator for 60 to 90 days. Then sow it on the surface of a moist, acid mix, uncovered, in light. Much of the seed fails to sprout, and many seedlings make runners but little fruit, so growers start fruiting beds from rooted cuttings.

Water daily for the first week or two, then every few days until the runners take hold, using fresh water, never salty. Mulch the bed with pine boughs over winter where snow is thin, since frozen ground and drying winds can strip the leaves. Every two or three years, spread half an inch of sand over the bed, which encourages upright shoots and keeps weeds down.

Each flower carries both male and female parts, and a lone plant sets fruit with its own pollen. Pollen from another plant brings more seeds and larger berries, so plant two or more from different seed. Rooted plants often flower and set a few berries the year after planting, and more the next. Cranberry fruitworms, weevils and fruit rot are its main troubles, and young growth may need cover on frosty spring nights.