Hazelnut Tree Pollination – Do Hazelnut Trees Need To Cross Pollinate

Corylus spp. Hazelnut trees are valued for their delicious nuts, which are used in a wide range of culinary applications, from desserts to savory dishes. Hazelnut trees are also prized for their ornamental beauty, with lush green foliage and catkin-laden branches that add interest to gardens and landscapes. However, knowledge of the pollination needs of hazelnut trees is crucial to a successful harvest for both the home gardener and the commercial grower. One of the most common questions is whether hazelnut trees need to cross-pollinate to produce nuts. The answer is simple and complex, depending on the species, variety, and environmental conditions.

The Basics of Hazelnut Pollination

Pollination is defined as the process of transferring pollen from male reproductive structures or anthers of a flower to the female reproductive structures, the stigma. Hazelnut trees have nuts with unique characteristics that vary for each kind:

Monoecious Nature: Hazelnut trees are monoecious, with male and female flowers occurring on the same tree. Male flowers look like long, dangling catkins, whereas female flowers are small and bud-like, with red, thread-like stigmas protruding from the buds.

Wind Pollination: Most fruit and nut trees require insect pollination. However, hazelnut trees are wind-pollinated, with pollen being transferred through the air and deposited onto female flowers by wind currents.

Flowering Timing: Hazelnut trees show dichogamy. This means that male flowers are mature and female flowers are immature on the same tree or vice versa. Such a timing prevents self-pollination and hence makes cross-pollination a vital process in nut production.

Importance of Cross-Pollination

While hazelnut trees are technically self-pollinating, they are only partially self-fertile. This implies that while one tree can pollinate itself to some extent, the quantity and quality of the nuts will be far higher if cross-pollination occurs. Cross-pollination refers to the process of pollen transfer between two genetically different trees belonging to compatible varieties.

Some of the major reasons why cross-pollination is crucial for hazelnut trees are as follows:

More Abundant Nut Set: With cross-pollination, a greater proportion of the flowers is fertilized to produce an abundance of nuts.

Better Nut Quality: In cross-pollination, more abundant and well-formed nuts often grow larger than self-pollinated nuts that grow smaller or deformed, as well as inferior in quality.

Increased Genetic Diversity: Cross-pollination increases the genetic diversity among the hazelnut trees and helps improve resistance against pests and diseases and even to environmental stressors.

Compatibility Problems: Most hazelnut species are partially self-incompatible, and thus they cannot pollinate their own flowers. To obtain nuts, they need to be cross-pollinated with a compatible variety.

Selection of Compatible Varieties

This is one of the most important considerations when establishing a hazelnut orchard or garden: selection of compatible varieties for cross-pollination. Compatibility requires that the release of pollinum from male catkins overlaps in time with receptivity by female flowers. The time is sometimes referred to as the pollination window.

The following are tips on choosing compatible varieties:

Find or research Pollination Groups: These are hazelnut varieties in separate groups by blooming time, so select to ensure overlapping blooms.

Plant Two or More Types: For ideal pollination results, plant at least two or more different hazelnut varieties at close proximity with each other.

Consult Local Experts: Local extension services, nurseries, or hazelnut growers can provide valuable guidance on selecting varieties that perform well in your region and are compatible with each other.

Consider Pollinizers: Some hazelnut varieties are specifically bred as pollinizers, producing abundant and viable pollen. These varieties are often planted alongside nut-bearing varieties to enhance pollination.

Environmental Factors Affecting Pollination

Several environmental factors affect the pollination of hazelnut trees, and it will prove very instrumental in the optimizing nut production, knowing and regulating these factors:

Wind Conditions: Since hazelnut is mostly wind-pollinated, good airflow should prevail. Avoid placing hazelnut trees in low-circulating areas or at a location that does not readily allow the current of air to pass by.

Extreme weather conditions such as heavy rain, frost, or high humidity will disrupt the dispersion of pollen and indirectly lower pollination success. Sheltering can be provided by locating trees in a suitable area.
Spacings for trees should be made such that there is free air circulation and unhindered diffusion of pollen from one tree to another. Overcrowding plantings can often prevent pollination.

Pollen Viability: It may be impacted negatively by temperatures and humidity levels. Cool dry weather often favors pollination and movement.

Practical Tips to Facilitate Good Pollination and Subsequent Production of Nuts

Here are practical tips to raise the chances for successful pollination and subsequent production of nuts from your hazelnut trees.

Grow Several Compatible Varieties: Because cross-pollination between compatible varieties can guarantee successful cross-pollination, growing several varieties maximizes the possibility of successful pollination.

Keep Track of When Male and Female Flowers Bloom: Track when male flowers bloom and when female flowers bloom and overlap. This will allow you to pinpoint potential gaps in pollination and take corrective action.

Use Supplemental Pollination: In situations where the natural pollination is not sufficient, you can transfer pollen using a soft brush or by shaking catkins over female flowers.

Keep Your Tree Healthy: Healthy trees are more likely to produce fertile pollen and open flowers. Make sure your trees have enough water, nutrients, and pest management practices to ensure they are as healthy as possible.

Provide Windbreaks: Even though wind is a critical part of pollination, high-speed winds can shatter flowers and prevent the pollen from traveling. Strategic windbreaks can help in controlling the wind speed.

Popular Hazelnut Varieties and Their Pollination Needs

Some of the most popular hazelnut varieties along with their pollination requirements are:

‘Jefferson’: It is one of the widely cultivated varieties, known for its good yield and disease resistance. Cross-pollination with varieties such as ‘Eta’ or ‘Theta’ is required.

‘Barcelona’: It is a classic variety that provides large, flavor nuts. The cross-pollination with ‘Daviana’ or ‘Ennis’ is recommended.

‘Tonda di Giffoni’: It is an Italian variety considered highly valued due to its high-quality nuts. Compatible with ‘Hall’s Giant’ or ‘Cosford.’

‘Yamhill’: It is a compact variety that is great for smaller places. Cross-pollination with ‘Jefferson’ or ‘Theta’ is recommended.

Conclusion

However, hazelnut can reproduce through self-pollination, but its cross-pollination is absolutely required for its good nutting and quality production. With such knowledge about what a hazelnut tree needs in terms of pollination and all the measures towards successful cross-pollination, you will see a rich harvesting of tasty nuts. Whether you are a home gardener or a commercial grower, taking the time to choose varieties that are compatible with each other, to manage environmental factors, and to keep the trees in good health will be repaid with vigorous hazelnut trees and plentiful harvests.

Related Posts

Hazelnut Growing: How To Grow Filbert And Hazelnut Trees

Hazelnuts are commonly referred to as filberts. Among the most desired nuts, these are prized for their rich flavor, high nutritional value, and versatile culinary uses. Growing hazelnut trees can…

Trimming A Walnut Tree: How To Prune Walnut Trees Properly

Although it is a prized timber and wonder nut; it remains equally healthy in shape and productivity if often pruned. The pruning of a walnut tree is more than just…

Leave a Reply

Your email address will not be published. Required fields are marked *

You Missed

Edible Herb Gardens: Tips For Growing A Culinary Herb Garden

Edible Herb Gardens: Tips For Growing A Culinary Herb Garden

Hazelnut Growing: How To Grow Filbert And Hazelnut Trees

Hazelnut Growing: How To Grow Filbert And Hazelnut Trees

Sweet Flag Care: Tips For Growing Sweet Flag Grass

Sweet Flag Care: Tips For Growing Sweet Flag Grass

Pergola Climbing Plants – Easy-Care Plants And Vines For Pergola Structures

Pergola Climbing Plants – Easy-Care Plants And Vines For Pergola Structures

Common Types Of Holly Shrubs: Learn About Different Holly Plant Varieties

Common Types Of Holly Shrubs: Learn About Different Holly Plant Varieties

Tips For How To Kill English Ivy

Tips For How To Kill English Ivy