Which Trees Have Catkins?
When out and about wandering the wilds have you noticed catkins on the trees? Depending on what time of year you’re looking they can be small and closed up or they could be large, mature, pendulous flowers, dangling like lambs tails in the breeze. They can be a very useful sign to help us identify what species of tree we are looking at.
In this blog I’ll explain what catkins are, when you can see them on different tree species and which trees have catkins. If you love trees, but struggle to tell one species from another, then you could enroll in my FREE Tree Identification Course online. More details can be found at the end of the article.
You can also get your hands on a free download; Spring Trees Catkin Guide which you can find below.
What Are Catkins?
Catkins are made up of a hanging spike of tiny flowers, which begin their lives all closed up but will mature and open as spring approaches. Catkins release pollen which is reliant on the wind to blow it over to a waiting flower. As a general rule, the catkins open up and mature before the leaves appear on the tree. The reason for this is so that the leaves don’t get in the way of the pollen travelling on the wind, so the chances of pollination are increased – nature’s pretty clever like that. Typically there are a lot more of the male catkins on the tree than the female flowers, again giving the tree the best chance at reproduction.
In the majority of tree species, catkins are usually male, but this is not always the case. With willow trees there are separate male and female catkins which only grow on separate trees. So they are reliant on there being the opposite sex tree within reach of the wind.
Goat Willow (Salix caprea) has striking catkins in early Spring. The males (left) and the females (right) appear on separate trees.
When Do Catkins Appear?
On some native trees the new catkins can appear as early as the autumn, when they will be short, closed up and firm to the touch. These will hang around on the branch through winter as they slowly swell and mature. If you’re seeing these young catkins on a tree in winter then it’s most likely one of the following; alder (Alnus glutinosa), birch (Betula spp.) or hazel (Corylus avellana), these are the most common.
Alder (Alnus glutinosa) on the left and birch (Betula spp.) on the right. Young catkins appearing in autumn.
In late winter the hazel tree’s catkins undergo a transformation as they swell in size, open up and release their pollen to the striking but tiny scarlet flowers. They are a beautiful but often overlooked splash of colour at this time of year, if you can find them. The catkins themselves are notable in late winter because they are maturing well ahead of any other native tree. Give the mature catkins a little tap and you might well be rewarded with a cloud of pollen puffing from the flowers.
Hazel (Corylus avellana) is the first native tree to give us a striking splash of colour in late winter, even if it is tiny. A country nickname for the catkins is “lambs tails”
In early spring it’s the turn of the willows and poplars to open up their catkins and this makes these species much easier to recognise than at any other time of the year. As we get to late spring, the female willow flowers have been pollinated and we get those distinctive white fluffy catkins of seeds which float on the wind and litter the pavement and curb-side, the bane of street-sweepers everywhere. I think they look quite nice though.
The fluffy pollinated seeds of the Goat Willow (Salix caprea) these are the mature female catkins. Seeds then spread by wind-dispersal.
Here’s a list of all our native tree species which have catkins, at one time of the year or another:
Alder, Aspen, Black Poplar, Birch, English Oak, Grey Poplar, Hazel, Hornbeam, Sessile Oak, Sweet Chestnut, Willows and White Poplar
Discover more About Trees
It can be so interesting to really look in to the details of our native trees and notice the changes that they undergo throughout the four seasons. That’s just what I’ve created for my FREE introductory online course called Kickstart Your Tree ID Skills. Here you will find a whole host of resources to take you from clueless to confident on your way to really knowing your trees.
REGISTER FOR THE FREE COURSE HERE
When you sign up to this free mini-course you’ll be identifying common trees with video tutorials and photo galleries at your fingertips. Start your journey to becoming a fully fledged Tree Expert today. The course includes Tree ID Cheat Sheets which you can download and take outdoors with you.
“I’ve been frustrated for so long trying to learn my trees myself and haven’t gotten far. This course answered everything and has seriously upped my game.” Dr. Patrick Alexander
FREE Spring Trees Catkins Guide
I’ve created a quick reference pictures guide to 9 of our native and common trees which produce catkins from late winter to early summer. I’ve arranged them in order of when their catkins appear too so you know not only what to look for but when to look for it. I hope you find it useful.
Happy tree hunting folks.
James
