Hazel catkins

admin
, 16 February 2019
Hazel catkins
© Mark Monk-Terry

By Charlotte Owen

WildCall Officer

It may not seem like the best time of year for botanising but there are some unusual flowers in bloom in February.  Alongside the familiar clumps of snowdrops, thousands of yellow hazel catkins are ripening in the winter sunshine.  They are flowers, despite appearances.  A typical flower has showy petals, sometimes with an elaborate pattern, a source of delicious nectar and maybe an alluring scent, and these are all features designed to attract bees and other pollinators.  But the hazel does not rely on insects for pollination, and there aren’t many around this early in the year, so it has no need to attract them.  Instead, the hazel relies on the wind and its flowers are designed accordingly.

The catkins are the male flowers and they produce copious amounts of powdery yellow pollen.  Each catkin actually consists of 240 individual flowers arranged on a dangling stem, and when fully ripe it only takes the slightest touch to release a cloud of microscopic pollen grains.  These can be carried over a great distance on a favourable breeze in the hope of reaching their intended target, a female hazel flower.  Of course, wind dispersal can be a bit haphazard and a lot of the pollen will be wasted, landing on damp branches, sticking to spider webs or dusting unsuspecting birds – but the sheer volume of pollen produced helps improve the odds.

The female flowers are tiny, so you’ll have to look a lot closer to spot them, but every hazel produces both male catkins and female flowers (but cannot pollinate itself).  The female flowers are equally unusual and resemble a scaly green bud with a bundle of delicate red tendrils emerging from the top.  These are the female flower’s styles, or pollen tubes, and any wind-blown pollen grains that land on them will fertilise the flower and trigger the development of a hazelnut. 

Even the name is a bit strange.  Catkin is derived from the Dutch word katteken, which means kitten, since the flowers look like fluffy kitten tails.  They’re also known as lamb’s tails for the same reason, and this name has a stronger association with the onset of spring.

Hazel flower

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Comments

  • Dr Leonard Barrett:

    Thank you for that information. I’ve been wondering for years how the hazel tree was pollinated
    especially as the male catkins appear so early in the Autumn with the female flowers so relatively insignificant.

    05 Jan 2023 15:50:00

  • G. Nash:

    I gather that tho catkins should have not yet appeared, climate confusion with all its horribly mixed messages, has certainly impacted on our male catkin bedecked hazel tree.

    07 Jan 2023 09:31:00

  • Tony Brown:

    Just checked out the females on the Hazel outside my static. Amazing.

    18 Feb 2023 12:51:00

  • Sophie McKee:

    Are there other trees/ shrubs which produce both male and female flowers please?
    Thank yoi

    20 Feb 2023 07:21:00

  • Sussex Wildlife Trust:

    Plants that have both male and female flowers in separate structures on the same plant are known as ‘monoecious.’ This quite literally means 'one house.' This contrasts with 'dioecious' plants ('double house') which is where male flowers are on one plant and female flowers on another.

    There are a huge number of examples of each. Most of our common trees are monoecious, so Birches/Oaks/Pines/Spuces... Ironically, almost all of the Willows are actually dioecious.

  • philip weaver:

    You certainly need your specs to see that pretty little red flower. Thank you, most interesting.

    16 Feb 2024 18:21:00

  • Adrian Breeman:

    Never seen the flower, very interesting I must look closer.

    27 Feb 2024 16:18:00

  • andy tilbrook:

    It is 20th August 2024. The Hazel tree at the back of my garden has a significant number of catkins growing. Any idea as to what may be causing this? I live in Pulborough.

    20 Aug 2024 11:37:00

  • Sussex Wildlife Trust:

    In rare cases, some trees might produce a second set of catkins in late summer or early autumn, though this is not common for Hazels. Sometimes Trees can produce flowers or catkins out of season as a stress response to factors like drought, disease, or damage.

  • Israel:

    The text is very suggestive. It is written in a delicate, elegant way. It is very nice to see the nature explained in such way. Thanks for it.

    22 Feb 2025 16:10:00

  • Alec West:

    I am amazed at the number of hazel trees by the roadside in the vale of York area, but very few of them bear nuts each year. I assume it is because of common late frosts. This year’s warmer than average spring and the last two days frost seems to have damaged these early flowers. Could hand pollinating before the frost allow the formation of nuts even if the female flowers are then later blackened by frost?

    01 Mar 2025 15:07:00

  • Sussex Wildlife Trust:

    Hazel is a native species, well adapted to the vagaries of the northern European climate and it doesn’t need to produce seed every year in order to successfully reproduce. If the conditions at the time of pollination aren’t ideal, then the plant doesn’t expend unnecessary energy trying to produce seeds in sub-optimal conditions. When the conditions are suitable then the plant expends more energy in seed production.

  • Bernard Bentley:

    Hazelnuts are very early this year in Fife,
    And can already see very small catkins on the branches.
    I haven’t even started pruning the bushes, out of respect for the neighbours.
    What is the prognostic for next year?

    24 Aug 2025 18:04:00

  • Sussex Wildlife Trust:

    In a ‘mast year’ Oak trees produce a bumper crop. As a result, far fewer acorns will be produced in subsequent years as the tree recovers from its mammoth reproductive effort. Interestingly, producing fewer nuts for several consecutive years may also benefit trees by keeping mice and other acorn predators under control, limiting their numbers via short rations. This year, the reason for the abundance of early fruits and nuts across the board is likely a stress reaction from so little rainfall, so plants 'overproduce' their seeds. What happens next will depend on the weather, but it's likely to be less, given the energy it will have taken to produce so much this year.

  • Linda Gregory:

    I have catkins on my hazel nut tree now when will the nut s appear

    08 Oct 2025 09:15:00

  • Kizzy:

    I have a hazelnut tree in my garden last year it’s was brimming with nuts…only issues are it’s attracting rats that are burrowing lots of holes underneath the concrete plinths of our fence, squirrels too and one year they got into our loft via the wall cavities! We have replaced the outside vents with metal ones but I still don’t want rats and squirrels, because they make such a mess of the garden taking one bite the nut and then discarding it I’m forever having to pick up nuts and my grandkids can’t play in the garden. I was going to reluctantly cut the tree by back any other suggestions I can do so that the tree stops producing nuts?

    30 Jan 2026 12:26:00

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