Is A Nut Tree For You?

Almonds, walnuts, cobnuts and chestnuts are a rare sight on modern plots. Fruit-growing professional Stephen Shirley reveals the varieties that are ripe for revival.

Almonds

Best for: Incorporating into the flower border or growing on the patio.

In short: The mass of delicate pinky-white flowers in spring will give any ornamental tree a run for its money; the nuts follow in late summer.

Where to grow:Plant the tree where it will be seen so as to make the most of the spring blossom. Almonds prefer full sun but will soldier on in all but the deepest shade. They lend themselves well to training in a fan-shape – a south-west-facing wall or fence is ideal for growing them against.

What to do: Make sure you buy a tree on a dwarf or dwarfing ‘rootstock’ – St Julien A is the most common. Imported trees are often grown on ‘Myran’ or seedling almond rootstocks – both of which will cause them to grow huge.

Almond trees are closely related to peaches and nectarines (you can actually eat the outer flesh in exactly the same way). Like them, they flower and fruit on two-year-old wood – so avoid overzealous pruning. Any cutting back is best done after the tree has flowered and set its crops.

In ideal conditions, as the almonds themselves grow, the fuzzy grey-green outer casing will harden and mature and, in early summer, begin to split open. This widens, exposing the familiar almond shell and allowing the kernel inside to dry. If the weather is less than perfect, you will more likely have to pick the still-green crop and cut the casing to get to the stone.

VARIETIES TO TRY

‘Lauranne’ – A relatively new, self-fertile variety which produces good quality nuts.

‘Macrocarpa’ – A white-flowered variety with soft-shelled nuts. It’s self-sterile so will require a pollinator.

‘Robin’ (also known as ‘Robijn’) – Probably the most popular almond and for good reason; it’s self-fertile and puts on a
good display of flowers followed by a heavy crop of soft-shelled nuts. It’s also all-but-immune to peach leaf curl.

GYO tip

To prevent peach leaf curl taking hold, most trees will need protecting from spring showers to reduce the risk of the air-borne spores – also carried in raindrops – finding their target.

Cobnuts

Best for: Smaller gardens, containers or growing as a productive hedge.

In short: Cobnut has come to be the catch-all term for cultivated (as opposed to wild) British hazelnuts. It is the classic English nut and definitely the easiest to look after.

Where to grow: Cobnuts can be grown as single trees but are better off in groups to ensure good pollination. Consider growing them as a hedge or shelter belt to your veg plot.

What to do: Cobnut trees actually need no attention at all and will still produce a good crop of nuts every year. The snag is, without pruning they will grow up to 6m in height, making picking the fresh green nuts tricky (they’re delicious chopped into salads) and the only easy way of harvesting them will be to wait until they’re fully ripe and then shake them off the tree.

Traditionally cobnuts are kept at around 2m as a single stem or multi-stem bush. Between November and mid-April simply remove anything that is dead, diseased or damaged, and any unwanted suckers (mini-trees) growing around the trunk. Then thin out the top growth to allow good circulation (you should have six to eight main framework branches) and trim down to around the 2m mark.

VARIETIES TO TRY

‘Kentish Cob’ – The most popular commercial variety and very reliable.

‘Princess Royal’ – Produces a small and dainty nut that looks all the more delicate because of the subtle pink hue to its husk.

‘Webb’s Prize Cobnut’ – Bears nuts that have a gorgeous sweet flavour whether eaten green or left to ripen on the tree.

Sweet Chestnuts

Best for: A woodland garden (or at least a very large one).

In short: Sweet chestnuts are self-fertile, so growing one is sufficient for a good haul of the delicious, prickly-skinned crop.

Where to grow: If you are going to allow your tree to grow to full size, a large open space is essential – some fully-grown
sweet chestnuts can reach a height of 35m in height with a trunk girth of 1.8m and a spread of 12m or more. Comparatively compact varieties such as ‘Glaberrima’ and ‘Marron de Lyon’ are available (taking 50 years to reach a height of 9m) and trees can be kept to a more manageable size by using root control bags (see box above) and sticking to a strict pruning regime.

What to do: If you’re growing them to full size, they are best left to their own devices – simple as that. If you plan to control the size of your tree, prune in autumn or winter to maintain a height of around 3.5m or so – a root control bag will help limit growth but is not essential. Aim to form a wine glass shape with a fairly open centre to allow good circulation within.

VARIETIES TO TRY

‘Canby Black’ – Bears large and very flavoursome nuts that peel easily.

‘Marron de Lyon’ – A reliable French variety that crops from an early age (two to three years). It has a compact growth habit and produces nuts with large single kernels (most sweet chestnuts produce two to four smaller ones).

‘Paragon’ – Another producer of single kernels – but harder to get hold of.

GYO tip

If you’re roasting the nuts, especially on an open fire, prick them first – otherwise they will likely explode and fly across the room.

Walnuts

Best for: A larger plot or ornamental garden.

In short: As worthwhile as an ornamental tree as it is as a food producer.

Where to grow: A walnut tree needs its own space – both its roots and leaves release juglone, a chemical which inhibits nearby plant growth. Avoid planting anything under or within a few feet of the eventual canopy of the tree (the roots underneath will spread as far as the tree on top unless they’re restricted by a root control bag). Walnuts will grow fairly large if they’re not pruned back (up to 15m in height with a spread of 9m) so open space is required. With careful pruning, a fruiting bush with a spread of around 3.5–4.5m can be produced.

What to do: If you’re planning to control the growth of your tree it is important to keep to a regular pruning regime. As soon as they have produced five or six leaves of growth, start cutting back the tips of branches – and continue to do so throughout the growing season.

VARIETIES TO TRY

‘Broadview’ - Apomictic (produces nuts without pollination), very hardy and late into leaf so rarely damaged by frost.

‘Franquette’ – Late coming into leaf and flower, cropping is unlikely to ever be affected by frost. Only partially self-fertile and relatively slow to come into bearing, but produces large nuts with a thick shell.

‘Rita’ – A small, manageable tree that flowers early – so crops can be susceptible to frost damage.

GYO tip

Clear up and burn the juglone-containing fallen leaves – certainly don’t add them to your compost heap, as then that will contain the chemical.

NUT TREE Q&A

When should nut trees be planted?
Bare-root trees can be planted throughout the dormant season (mid-November to late March while the branches are bare); container-grown trees can be planted throughout the year.

Are they harder to grow than other fruit trees?
No – the growing cycle of a nut tree is just the same as an apple or a pear, it’s just that you end up eating the seeds instead of the flesh.

At what age will they start producing nuts?
Cobnuts and almonds usually start cropping in their second year, sweet chestnuts and walnuts take longer – five to seven years.

Can I propagate them from existing stock?
Nuts are, of course, the tree’s seed – but just as you can’t sow the pips of a hybrid apple variety and expect to produce more of that exact hybrid, you cannot expect to sow a hybrid nut and produce a hybrid nut tree. Cobnuts are best for home propagation – they often produce suckers from the roots which can be carefully cut off and planted. They can also be rooted fairly easily from semi-ripe cuttings taken in late summer, or hardwood cuttings in winter.

Almonds can also be propagated from late summer or winter cuttings – but the tree will grow very large on its own roots and it is far better to buy a grafted hybrid. Sweet chestnuts are difficult to root from cuttings, walnuts even more so – both are best grown from nursery stock.

Do nut trees need to be pollinated to bear crops?
Just as when you buy fruit trees, pollination is an issue that needs to be considered; some nut trees are self-fertile (producing both male and female flowers), some are not – so seek advice when you are buying.

Can they be grown in planters?
Growing anything in a container smaller than its normal root area will restrict its growth rate and so affect its ultimate height and spread. Cobnuts and almonds will both perform very well in these conditions. While it is possible to grow sweet chestnuts and walnuts in containers – and with careful pruning for them to produce reasonable crops of nuts – ultimately they will need to be transplanted into the
open ground to survive.

Are root control bags necessary?
The special bags will restrict root growth (and so the ultimate size of your trees) just as growing in a container would do – but as the tree is effectively in the ground it’s much more stable. Used alongside a strict pruning regime, it is possible to keep larger trees such as sweet chestnuts and walnuts down to a more manageable size. The bags are available from most nurseries and garden centres.

Useful Contacts

Stephen Shirley is MD of Victoriana Nursery Gardens, which supplies a number of the nut tree varieties mentioned here – as well as a wide range of fruiting canes, bushes and trees and both herb and vegetable seeds. Call 01233 740 529 for a catalogue or buy online at www.victoriananursery.co.uk

The full as printed magazine article can be viewed here...