Hazel

About

February is the month hazel does something almost nothing else does. The catkins lengthen and open into yellow lamb’s tails on bare twigs, and if you look closely at the same branch you will find the female flowers, which are the size of a grain of rice and are the most vivid crimson thing in the whole winter garden.

Hazel is also the plant that built rural Britain. Coppiced on a seven to ten year cycle, it supplies the poles, hurdles, thatching spars, bean sticks and hedge binders that every farm needed, and it responds to being cut to the ground by growing back faster and living indefinitely. Some coppice stools in ancient woodland are thought to be over a thousand years old.

For a garden it gives catkins in February, a crop of nuts in September if the squirrels leave any, and an endless supply of pea sticks.

Appearance and character

A deciduous multi-stemmed shrub or small tree, 4 to 8 m if left alone and kept far smaller by coppicing.

Stems are straight, smooth and grey-brown when young, and a coppiced stool throws up dozens of them from ground level.

Leaves are rounded, 6 to 12 cm across, with a heart-shaped base, a sharp point and a doubly toothed edge, soft and hairy to the touch.

Male catkins form in autumn as small hard green tails, hang on all winter and lengthen in January and February to 5 to 8 cm of pale yellow, releasing clouds of pollen in the wind.

Female flowers are the thing to look for. Tiny buds on the same twig that open into a tuft of brilliant crimson styles just a few millimetres long, easy to walk past and remarkable close up.

Nuts ripen in September, held in groups of one to four in a ragged leafy husk, and the shell is pale brown and hard.

Twisted hazel, ‘Contorta’, is the corkscrew form grown for winter stems, and purple filbert, Corylus maxima ‘Purpurea’, has dark leaves and purple husks.

Where it is from

Europe and western Asia, including Britain, where it is native and grows in woodland, on woodland edges and in hedgerows on almost any soil.

Hazel was one of the first trees to recolonise Britain after the last ice age and was for a long time the commonest tree in the country.

Its history with people is unusually deep. Coppicing has been practised here since the Neolithic, and hazel rods from Somerset trackways have been dated to around 3800 BC, showing a managed coppice cycle already in use.

Coppicing works because hazel is adapted to regrow from the base after damage, and cutting resets the plant so completely that a managed stool outlives an unmanaged one many times over.

Kent is the centre of British nut growing, where the crop is called cobnuts and the orchards are known as plats.

Hazel coppice is one of the richest habitats in British woodland and is the classic home of the dormouse.

How it grows

Plant bare-root between November and March into almost any soil. Hazel is untroubled by clay or chalk.

Plant two different varieties if you want nuts. Hazel is monoecious, carrying both sexes on the same plant, and it is largely self-incompatible, so a lone plant sets very few nuts.

Space plants 4 to 5 m apart for nut growing, or 45 cm apart in a hedge.

Coppice on a seven to ten year cycle for poles, cutting all the stems to within 5 to 10 cm of the ground between November and March. Cut on a slight slope so water runs off.

Coppice in rotation rather than all at once. Taking a third of the stems every few years keeps a continuous supply and keeps the plant looking like something.

Prune a nut-growing plant differently. Aim for an open goblet on a short leg, and in August brut the strong side shoots by breaking them half through and leaving them hanging, which is the traditional method and encourages fruiting buds.

Remove suckers around the base of a plant grown as a tree.

Harvest nuts in September when the husks yellow. Picked slightly early they store better and the squirrels get fewer.

Expect nuts from year four or five, and a full crop from about year eight.

Through the seasons

Winter is catkins and cutting. The lamb’s tails open through January and February, and coppicing runs from November to March.

Spring brings the leaves in April, after the flowers. Late frosts can kill the tiny female flowers and cost the year’s crop.

Summer is growth. Brut the side shoots of a nut plant in August, and cut pea sticks and bean poles from earlier coppice growth.

Autumn is harvest. Nuts ripen through September, and this is when the squirrel problem becomes obvious.

Care difficulty

Easy. Hazel grows in any soil, in sun or shade, and it recovers from being cut to the ground.

Getting nuts is harder than growing the plant. A single specimen crops poorly, squirrels take what does set, and a late frost can remove the crop before it starts.

Coppicing is straightforward and the main decision is remembering to do it in rotation.

There is very little disease worth planning for.

Watering

Water new plantings through their first summer.

Established plants need no watering under British conditions.

A dry summer reduces the size of the nut crop, and watering a young nut plant during August helps the kernels fill.

Mulch a new planting to suppress grass.

Hazel tolerates damp ground better than beech and dislikes standing water.

Warning signs, diseases and pests

Grey squirrels are the reason most people never eat a hazelnut from their own tree. They take the nuts while still green, weeks before they are ripe, and they will clear a mature tree in a few days. There is no practical defence for a garden tree. Picking early, as soon as the husks begin to yellow, and ripening the nuts indoors is the only approach that reliably gets you a crop.

Nut weevil lays in the developing nut, and the grub eats the kernel and bores out through a neat round hole. Collect and destroy fallen nuts with holes, and cultivate the ground beneath in winter.

No nuts at all on a healthy mature plant usually means there is only one hazel. Plant a second, different variety.

Hazel big bud mite swells the buds into round galls that fail to open. Pick off affected buds in winter on a small plant.

Late frost in March kills the tiny female flowers and removes the crop for that year, and nothing can be done about it.

Powdery mildew and leaf spot both occur without threatening the plant.

Honey fungus and Phytophthora both affect hazel, and neither is common.

Growing environment

Full sun gives the heaviest nut crop. Hazel grows well in partial shade and crops lightly there.

Almost any soil, including clay and chalk. It prefers moist, well-drained ground and dislikes waterlogging.

Space of 4 to 5 m each way for a nut plant, or 45 cm apart in a hedge.

Shelter improves the crop, since the female flowers are wind-pollinated in February and a sheltered site holds the pollen where it is needed.

A hedgerow, a woodland edge, a boundary or the back of a large border all suit it.

It is one of the best wildlife plants available. Catkins feed early insects, nuts feed dormice, squirrels and jays, and coppiced hazel creates the light and shade that woodland flowers need.

Avoid a small formal garden, where the size and the suckering make it a nuisance.

Feeding

Hazel needs no feeding on ordinary soil.

A potassium-rich feed such as sulphate of potash in early spring helps a plant grown for nuts.

Avoid nitrogen, which produces long soft growth and fewer nuts.

Mulch with compost in spring on poor ground.

A newly coppiced stool regrows vigorously without any feeding at all.

Troubleshooting

Where are the female flowers? Tiny crimson tufts a few millimetres across on the same twigs as the catkins, in February. They are easy to miss and worth looking for.

My tree produces catkins but no nuts. Hazel is largely self-incompatible. Plant a second, different variety nearby.

The squirrels take everything. They do, and weeks before the nuts are ripe. Pick as soon as the husks start to yellow and ripen the nuts indoors.

Small round holes in the nuts. Nut weevil. Collect and destroy affected nuts and cultivate the ground beneath in winter.

How do I coppice it? Cut all the stems to within 5 to 10 cm of the ground between November and March, on a slight slope so water runs off. Do a third of the plant at a time to keep a continuous supply.

Will it regrow if I cut it right down? Yes. Hazel is built for it, and a coppiced stool outlives an uncut one many times over.

Swollen round buds that never open. Hazel big bud mite. Pick them off in winter.

Can I grow it in shade? Yes, and it will crop lightly. Full sun gives far more nuts.