Why Is My Hazelnut Harvest So Poor This Year?

You expected a basketful and got a handful. A poor hazelnut harvest is rarely caused by a single problem — it usually reflects a combination of weather timing, pest pressure, and management choices made months before harvest. Understanding what happened lets you intervene at the right points in the coming year.

Biennial Bearing

Many hazelnut varieties naturally fruit heavily one year and lightly the next. This alternate bearing pattern is often the simplest explanation for a suddenly poor crop following a bumper year. The tree exhausts its energy reserves producing a large crop and then scales back the following season to rebuild. Thinning an exceptionally heavy crop when the nutlets are pea-sized can moderate the swing and lead to more consistent annual yields.

Nut Weevil and Other Pest Damage

Hazelnut weevil larvae hollow out developing nuts and cause them to drop prematurely in midsummer. If you split open apparently empty shells and find a creamy grub or a brown hollow, weevil is the cause of your missing crop. The grubs pupate in soil beneath the tree, so collecting and destroying fallen nuts before the larvae exit reduces next year's population significantly.

Insufficient Cross-Pollination

Even gardens with two hazelnut varieties can suffer pollination failure if the catkins and female flowers are not synchronised. Some variety pairs have overlapping flowering windows; others do not. A cold snap during the brief female flower receptive period can also mean that although pollen was available, fertilisation did not occur. Planting three varieties instead of two widens the pollination window and increases the chance that at least one pairing succeeds each year.

Squirrel Predation

Squirrels begin raiding hazelnut clusters well before the nuts ripen, often stripping an entire bush in a few days during August. If your harvests are consistently disappointing in what seem like good flowering years, watch the tree in late summer. Squirrel-proof netting placed over individual branches or whole small bushes can protect enough nuts to make harvest worthwhile.

Drought at Nut Fill

Hazelnuts need consistent moisture as the kernel develops through July and early August. A dry spell during nut-fill causes small, shrivelled kernels or premature drop. Mulching generously around the root zone in spring retains moisture and reduces the impact of summer dry spells. Deep watering once or twice a week during dry periods in midsummer can double kernel weight in a difficult season.

Improving Next Year's Harvest

After a poor year: check the nuts you did collect for weevil damage, count how many varieties you have, review your pruning timing, and mulch deeply before winter. Each of these actions addresses a different bottleneck. Most gardens see a meaningful yield improvement within two seasons of tackling the underlying causes systematically.