A Celebration of Catkins

Dancing on bare branches in winter and spring breezes, or sitting placidly on stems like small, furry creatures, catkins are, in fact, groups of tiny flowers without petals. Some are male, others female, content in some cases to live side by side, in others, choosing to occupy their own individual space. Thus birch, sweet chestnut and walnut catkins appear on the same tree, while male and female poplar and willow catkins are produced by separate trees. Others, like oak and hazel, have male catkins and small, single, female flowers together.

So how did these flowers that don’t actually look like flowers come about? There is of course, as almost always where nature is concerned, a perfectly rational explanation. Some trees are wind-pollinated and it appears that catkins have developed as part of their evolutionary process. Cleverly shaped and positioned, the way that many catkins dangle allows them to catch the wind, which obligingly blows pollen from male onto female catkins or flowers.

Not all hang downwards however. Pussy willow and sweet chestnut, among others, have fluffy, upright male catkins. Which seems strange until you learn that both are pollinated not only by wind but also by insects. So perhaps this too is a part of a plan and these catkins have evolved to be a shape more attractive to and easier to access for pollinators. The natural world is in a perpetual state of experimentation.

Some catkins appear very early, in January and February, and others are at their peak later, right up until May. But all arrive either while trees are still bare of leaves or before they fully unfold. This would seem to be yet another cunning plan, allowing the passage of pollen as directly as possible to the female flowers without being caught by foliage and wasted.

It’s the female flowers or catkins that develop into nuts, while others like alder, poplar and willow, produce seeds which are dispersed by wind, sometimes helped by hairy coatings or tiny wings to boost their flight.

Catkins that care?

Like most other flowers, catkins are packed with pollen – blow on one when it’s ripe and watch the tiny grains puff into the surrounding air, touch one and your fingertip will be coated with fine, yellow dust. This pollen is popular with early bees, for while nectar provides carbohydrate in the form of sugar, pollen is protein. Bees emerging after winter are hungry and need this protein to build themselves up. Queens in particular require it in spring to produce eggs and the larvae that follow will be fed on a mixture of pollen and nectar sometimes called bee bread. Usually the gathering of pollen by insects is part of a reciprocal relationship – the harvesters are fed and carry out their duties as pollinators in return. But that often isn’t the case here since the wind is doing the pollination for most catkin-bearing trees. So there’s no immediately obvious advantage for them to supporting insects in this way. A few, however, like willows and sweet chestnut, do produce nectar and, intriguingly, are trees that are pollinated by insects as well as the wind.

Catkins in the garden

Willow

Popular for its delightfully tactile catkins is the male goat or pussy willow, Salix caprea, with its plump, furry, silvery buds, like velvet to the touch as they begin to emerge in early spring. As well as providing nectar for bumblebees, like other willows it supports the caterpillars of moths and butterflies including the purple emperor. It also provides nesting material and seeds for birds, some of whom will feed these caterpillars to their chicks. Like so many trees, it’s a small ecosystem in itself. Suitable for a large or medium-sized garden, it can become a substantial tree, growing up to 12m, but the dwarf, weeping form, ‘Kilmarnock’ only reaches around 2-2.4m tall.

The stunning upright catkins of Salix gracilistyla ‘Mount Aso’, which appear around the same time, are similar but an eye-catching rose pink, standing out against their leafless branches and adding glowing colour to the garden at a time when it can look dispiritingly bare. These are followed by green leaves with silvery backs. Another compact tree, it grows to around 3 or 4m tall. These late winter wonders are currently in stock at several Capital Gardens Centres. Pop the twigs of either or both trees into a glass vase for instant ikebana and a simple but elegant hint of spring indoors. There’s no need to add water.

There are many species of willow, all have catkins and most are quite large, but for those with a big enough garden, they’re a good investment. The bark of mature trees is beautifully and strikingly textured and several, including the iconic weeping willow, Salix babylonica and its hybrids, are naturally found growing alongside streams and rivers. Lovers of damp places, they do their bit to help suck up excess water. Their flexible twigs and branches have a multiplicity of uses – from weaving plant supports and pea sticks, living garden structures and baskets to frames for headdresses for participants in wassailing and May Day merriment.

Hazel

There are two types of hazel, Corylus avellana (cobnut) and Corylus maxima (filbert). Despite reaching about 12m tall they’re slow growing and can be kept in check if necessary by light pruning or coppicing. Their soft, early spring catkins look like yellow lambs’ tails.

For smaller gardens try compact cultivars C. avellana ‘Contorta’, the aptly-named curly hazel, with its fascinating, twisty branches or C. maxima ‘Gunslebert’ which grows to 6m tall and bears nuts in abundance from an early age. Also fairly small, C. avellana ‘Red Zellernut’ has pink catkins and leaves which move from purplish bronze in spring through summer green to burgundy as autumn sets in. While most hazels are self-pollinating this needs a partner plant such as the similarly-sized C. maxima ‘Purple Filbert’ to produce nuts.

Like willow, hazel’s pliable stems can be used in a number of practical and creative ways and they’re valuable wildlife trees too. Coppiced specimens are home to the endangered hazel dormouse, and the autumn nuts provide food for squirrels and woodpeckers as well as dormice preparing for hibernation. The leaves are food for nut tree tussock and large emerald moths.

Silver birch

Male catkins are long, yellow and straight, rather like those of hazels, while females are shorter, stouter and green until pollinated when they become dark rust in colour. Although they form in autumn and so are on display over winter, they don’t open until a few months later in April or May. Birch trees are mostly suitable for medium or large gardens but there are smaller varieties that work well in modestly-sized spaces. Another wildlife wonder plant, they provide food for many species of moths including the angle shades, pebble hook-tip and Kentish glory and the early summer seeds are eaten by redpolls, siskins and greenfinches. Birch twigs were traditionally used to make besom brooms, excellent for sweeping autumn leaves and spreading worm casts on lawns.

Often seen in winter gardens, where its silvery white bark appears almost luminous on a gloomy day, providing the perfect foil for colourful willow stems and evergreen foliage, is Betula utilis subsp. jacquemontii. It’s tall, at 18m but ‘Silver Shadow’ is smaller at around 8m, while Betula pendula ‘Youngii’, around the same size, is a weeping form with branches that trail gracefully earthwards.

There are others too. Majestic Juglans regia, with hanging greenish yellow male and spikes of bright green female catkins. Given lots of sun and warmth it will provide a feast of walnuts. Alder – Alnus glutinosa – whose female flowers look more like fir cones than catkins. Or Garrya elliptica, a large ornamental shrub, with evergreen leaves and generous quantities of long, silky, greyish green catkins in January and February. ‘Catkin’ comes from the Dutch ‘kattekin’, or little cat. Maybe because of the resemblance of some to cats’ tails, or perhaps a reference to the fuzzy coating on others. Whatever the reason, these hanging or furry clusters of miniscule flowers not only bring a touch of entertainment to winter and spring but help wildlife as well, supporting birds, bees and moths and encouraging them into our gardens.

https://www.treeguideuk.co.uk/mini-guides/catkins/ https://www.bbc.co.uk/blogs/gardening/2011/03/plant-support-weave-lattice.shtml https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/animals/mammals/hazel-dormouse https://www.capitalgardens.co.uk/blog/a-twist-in-the-lambs-tail-corkscrew-hazel/ https://www.google.com/search?q=how+to+make+a+besom+broom