How to Prune Blueberries: Which Canes to Cut and When

Where the fruit actually comes from

Flower buds form in late summer on the wood that grew that season, and they open and fruit the following spring. So this year's new shoots carry next year's crop, and anything you cut in winter is a decision about next summer's fruit rather than this one.

Canes are most productive at two to five years old. After that the wood thickens, the twigs it carries get shorter and twiggier, and the berries get smaller even though the total number of buds looks high. A bush left unpruned becomes a thicket of old canes carrying masses of tiny fruit, which is the most common state of a neglected blueberry.

Prune in late winter, while it is dormant

Do the main pruning in late winter or very early spring, before the buds swell but after the worst of the cold has passed. The bush is leafless so you can see the structure, wounds heal quickly as growth starts, and you can tell fruit buds from leaf buds because fruit buds are fat and rounded while leaf buds are small and pointed.

Pruning in autumn leaves fresh cuts exposed through winter and can stimulate growth that then gets frosted. Summer pruning is limited to removing dead or diseased wood and any low branches that let fruit touch the ground; cutting good wood in summer removes flower buds that have already formed.

1. Take out dead and damaged wood first Scrape the bark with a thumbnail: green underneath means live, brown means dead. Clearing this first shows you the real structure of the bush before you make any judgement calls.
2. Remove the oldest canes at the base Cut one or two of the thickest, grayest canes right down to ground level with loppers. On a mature bush, removing about a fifth of the canes each year keeps a continuous supply of young wood coming through.
3. Open the center Take out anything crossing through the middle, and any cane growing inward. Air and light through the center reduce fruit rots and ripen the interior fruit properly.
4. Cut out low, sprawling growth Branches that arch to the soil put fruit on the ground where it rots and gets eaten. Take them back to an upright shoot or remove them at the base.
5. Thin the twiggy tips The fine twiggy growth at the top of an older cane carries many small buds. Shortening those clusters back concentrates the plant into fewer, larger berries.

Fruit buds are visibly plumper and rounder than leaf buds by late winter. Learning to tell them apart on the bush in front of you is worth more than any general rule about how much to cut.

How much to take, by age of bush

The amount you remove changes completely with the age of the plant. A young bush needs almost nothing taken off except flowers, because it is building a framework. A mature bush needs a steady annual removal of old wood, or it drifts into unproductive congestion within a few years.

Never remove more than a quarter to a third of the wood in a single winter. A hard cut provokes a mass of soft growth and costs you most of the following season's crop.

Renovating a neglected bush

An old bush that has never been pruned is a mass of gray canes with fruit only at the very top and tips. It can be brought back, but not in one go. Cutting the whole thing to the ground does work in that it forces vigorous new canes, and it costs you two to three years of fruit and can kill a weakened plant outright.

The gradual approach is better. Over three winters, take out roughly a third of the oldest canes each year, always cutting to ground level rather than shortening. By the third year the bush is composed of canes one to three years old and cropping properly, and you have had some fruit throughout.

Keeping rabbiteye within reach

A rabbiteye left alone grows to fifteen feet (4.5 m) and puts its best fruit where you cannot reach it. Cap the height at about six feet (1.8 m) by cutting the tallest canes back to a strong outward-facing side branch rather than shearing across the top, which produces a dense brush of upright shoots.

Rabbiteye also suckers freely from the base, which is useful because it supplies replacement canes without effort. Select three or four of the best suckers a year to keep and remove the rest, or the bush turns into a crowded clump with no light reaching the middle.

Mark the canes you intend to remove with a loop of colored string in summer, when you can see which ones actually carried good fruit. In winter every cane looks the same, and that note is what turns guesswork into a decision.