Why Does My Apple Tree Only Fruit Every Other Year and How Do I Fix It?

Biennial bearing — also called alternate bearing — is the frustrating pattern where an apple or pear tree produces a massive crop one year, then barely any fruit the next. The on-year gluts you with more fruit than you can pick; the off-year leaves the tree looking healthy but barren. Once this cycle becomes established, it can be very difficult to break without deliberate intervention. Both pruning and fruit thinning have roles to play in correcting the problem.

Why Biennial Bearing Happens

When a tree carries an exceptionally heavy crop, it invests so much energy in developing that fruit that very few flower buds are set for the following season. Without flower buds, the following year produces almost no fruit. But this off-year gives the tree a full season to set an enormous number of flower buds — leading to another heavy crop — and the cycle perpetuates itself. A late frost that destroys blossoms in a normally heavy year can trigger the pattern, as can a severe drought or pest attack that strips the leaves when buds should be forming.

Which Varieties Are Most Prone

Some apple varieties are more prone to biennial bearing than others. Bramley's Seedling is perhaps the most notorious — left unpruned, it can swing dramatically between bumper and near-zero years. Blenheim Orange, Golden Noble, and some older heritage varieties are also inclined to alternate. Modern disease-resistant varieties bred in the last thirty years are often specifically selected for more consistent annual cropping. If you are planting new trees, check variety notes for biennial bearing tendency.

Fruit Thinning in the On-Year

The most effective intervention is aggressive fruit thinning in the heavy on-year, starting in June after the natural June drop has occurred. Thin to one fruit per spur cluster, and space remaining fruits at least 15 cm apart along the branches. This dramatically reduces the energy the tree expends on fruit and frees it up to set flower buds for the following season. It feels counterintuitive to remove so much fruit, but a moderate well-thinned crop in the on-year is the price of a reasonable crop in the off-year rather than nothing at all.

How Pruning Helps Break the Cycle

Harder pruning in the on-year reduces the total number of fruiting spurs available and therefore limits how large the crop can become — which limits the energy deficit that triggers the off-year. Spur thinning — reducing the number of buds on each spur cluster — achieves a similar effect. Some growers also try harder pruning in the off-year to stimulate new flowering wood, but this is less reliably effective than thinning fruit in the on-year. The two interventions together — thinning fruit and pruning spurs in the on-year — give the best chance of gradually restoring annual cropping.