How to identify catkins
Trees festooned with catkins are a sure sign that spring has finally arrived. Our expert guide looks at which species of British tree has catkins, the role they play in pollination and how to identify catkins, plus where to see.
Catkins start to appear on trees in the late winter months and provide a cheering sign that spring is on the way. Catkins are easily identified by its long, slim shape and spiky texture. Catkins play an essential role in tree reproduction and can be found on hazel, silver birch and white willow trees among other species.
For a few weeks each year, catkins release pollen into blustery March breezes, then fall the leaf canopy unfolds. As they are blown in the breeze, the female flowers are pollinated by the pollen from the male flowers.
Enjoy them while you can with our guide on how to identify catkins and tree species that have catkins.
What are catkins – and what do they do?
A catkin is a long slim flower which often has no petals. Catkins allow a tree to reproduce as the female flowers are pollinated by male flowers. This happens when the seed is dispersed by the wind or by insects which play an important role in helping pollination happen.
Which trees have catkins?
Hazel - Corylus avellana
Golden catkins on bare twigs release clouds of yellow pollen that seem to dissolve in the air, destined for tiny female flowers that are just clusters of carmine stigmas protruding from a bud.
Alder - Alnus glutinosa
Longer, more knobbly and darker than hazel, these are the first catkins to shed pollen in spring. They’re carried on the tips of twigs, often alongside clusters of tiny red-tipped female flowers.
Goat willow - Salix caprea
This has separate male and female trees. Male catkins are clad in golden stamens; female catkins are spiky and green. Both secrete nectar – key energy for bees and butterflies in early spring.
Silver birch - Betula pendula
Male catkins elongate and shed pollen at the same time as leaf buds open. Female catkins are short and point upwards, hanging downwards after pollination, when the seeds develop.
Trees also provide a habitat and food for wildlife, creating an ecosystem where birds, insects and other creatures can live.
Can you spot an oak from a horse chestnut tree? Learn how to identify common tree species and the best places to see with our expert guide on British trees.
White poplar - Populus alba
These long, fat, red-tinged catkins are often carried at the top of the tree, so you may need binoculars to appreciate them. Easily dislodged by wind, they litter the ground after a gale.
Walnut - Juglans regia
The short, fat, green catkins shed pollen at the same time as the leaf buds release their grip on the purple-hued foliage. Female flowers are shaped like little pots, tipped with a pair of curved stigmas.
More like this
Phil Gates taught biology at Durham University and writes for The Guardian’s Country Diary column.