Persimmon and Kaki: Growing, Hardiness and Ripening It Right

When the leaves have long since fallen in November and the garden turns grey, one tree still carries dozens of glowing orange globes. That is the moment kaki gardeners live for. The persimmon carries its fruit well into late autumn, and it is exactly this late, almost defiant ripeness that makes it one of the most exciting fruit trees for mild sites. There is only one thing you must understand before your first bite: an unripe kaki of the wrong variety tastes so mouth-puckering that you spit it straight back out. Ripe, on the other hand, it is honey-sweet like almost no other fruit.

Kaki, persimmon, sharon: sorting out the names first

All three names mean the same species, the East Asian Diospyros kaki. Kaki is the common German trade name, persimmon the slightly more refined variant, and sharon is really a brand: a low-tannin kaki bred in Israel that you can eat crisp. In the garden what matters most is the difference between two fruit types, because it decides when and how you harvest.

Astringent varieties contain a lot of soluble tannin when unripe. That is the substance that draws your mouth together, much like a very young red wine or an unripe sloe. You have to let these varieties turn glassy-soft, and then the tannin is bound and the fruit turns sweet. Non-astringent varieties like 'Fuyu' lose their tannins on the tree and can be sliced firm like an apple. For the cooler DACH region, though, it is often the astringent, very frost-tolerant types that are the more reliable ones.

The right spot: warm, sunny, sheltered from wind

The kaki is a sun-worshipper. It wants a full-sun spot with at least six hours of direct sunlight, ideally against a south wall that stores warmth during the day and releases it at night. In the wine-growing climate of the Kaiserstuhl, the Moselle, the Rhine valley or the mild alpine foothills it now stands against many house walls and bears reliably. The harsher your site, the more important the sheltered, warm corner becomes.

It is less fussy about soil but likes it loose and free-draining. Ideal is a sandy-loamy, humus-rich soil with a neutral pH around 6.5 to 7.5. It does not tolerate waterlogging at all, so loosen heavy clay soils generously with sand and mature compost before planting. If you already keep figs, olives or citrus in the garden, you usually have the right corner: the same warm south aspect these Mediterranean guests love suits the kaki too.

The kaki's loveliest side effect is its autumn display. First the large, glossy foliage turns strong yellow, orange and red. Then it falls, and the fruit is left alone on the bare branches. This picture, orange fruit against a grey November sky, is why many discover the kaki as an ornamental tree first and only afterwards notice how good it tastes.

A single tree is enough for a harvest, by the way: most garden varieties are self-fertile and set fruit even without a pollinator, often seedless at that.

Planting and guiding the first years

The kaki is best planted in spring, once no hard frost threatens any more, from about CW 15 to 18. That gives the tree the whole season to root in before its first winter. Container stock can be planted over the summer if need be, but then water it consistently.

1. Dig the hole generously

   Twice as wide as the root ball, mixing the spoil with compost and, on heavy soil, with sand.

2. Do not plant too deep

   The graft union stays clearly above soil level. Water the tree until the ground has settled.

3. Mulch the tree base

   A thick layer of leaves or bark mulch holds moisture and protects the shallow roots from frost.

4. Wrap the trunk for the first winters

   Wrap young trees in jute or coir matting, and lay brushwood over the tree base.

5. Feed sparingly

   Compost and a little horn meal in spring, nothing at all from August so the wood can ripen.

Feeding in particular is a common mistake. Too much nitrogen pushes the kaki into soft, long leafy growth that fails to lignify in time in autumn and then frosts easily. Less is more here: mature compost in spring, plus potassium-rich organic material for fruit set, and stop from midsummer.

Container culture for colder gardens

If you do not live in a favoured wine-growing climate, a pot is your safest route to your own kaki. In a container the tree stays smaller, and you can move it somewhere frost-free over winter. The big advantage: the kaki drops its leaves and needs practically no light in its winter quarters. A cool cellar, a garage or a frost-free garden house at around 0 to 8 degrees is entirely enough.

Take as large a vessel as possible with good drainage, a hole in the base is a must. Substrate: high-quality container compost, lightened with sand or expanded clay so nothing gets waterlogged. From May to September the pot stands outside in full sun, and in summer it is watered daily, because the soil in a container dries out fast. Before the first night frost, usually around CW 43 to 45, you bring young potted plants indoors. Older, robust potted kakis can stay outside too, but then wrap the pot and trunk thickly and set the vessel on a sheet of polystyrene.

Anyone who already overwinters olives or citrus in pots knows the routine, and the kaki is actually the easier of the bunch: no evergreen foliage yellowing in the dark quarters, no fight with scale or mealybug in the warmth. It simply stands bare and patient in the cool, waiting for spring.

Harvest and after-ripening: the decisive step

Now comes the part where most kaki newcomers fail. The fruit ripens late, often only once the leaves have already fallen, typically from CW 43 to 48. Full colour alone is not a reliable sign: astringent varieties are frequently rock-hard and puckering even when deep orange. Only once the fruit turns soft and almost glassy is the tannin bound.

You have two routes. Either you leave the fruit on the tree until it softens on its own, which a touch of frost even speeds up. Or you harvest it firm when snow and storms threaten and let it after-ripen indoors. To after-ripen, put the kakis in a bowl together with apples or bananas: their ethylene speeds the process up markedly.

How do you recognise perfect ripeness? An astringent kaki is ready to enjoy when it feels like a ripe tomato, almost too soft to pick up. The skin turns thin and translucent, the inside pudding-soft. Then it is best spooned out like a soft-boiled egg. The crisp 'Fuyu' types, by contrast, you eat firm: peel, cut into wedges, done. A sure sign with the after-ripeners is the calyx, which lifts off easily once the fruit is through.

Ripe kakis keep for only a few days. Whatever you do not eat straight away you turn into jam, chutney or fruit leather, or you freeze the purée in portions. In East Asia, astringent kakis are traditionally peeled and air-dried into Hoshigaki, sweet dried fruit with a white bloom of sugar.

Varieties for the German-speaking region

Not every supermarket kaki is fit for the garden. When buying, look for varieties described as frost-hardy and proven for Central Europe.

• 'Rojo Brillante': the big Spanish commercial variety, astringent, very productive, needs warmth and full after-ripening.
• 'Fuyu': the best-known crisp-fruit type, non-astringent, mild-sweet, but heat-demanding.
• 'Nikita's Gift': a hybrid with the American Diospyros virginiana, very robust and recommendable for harsher sites.
• 'Rossijanka': one of the most frost-hardy varieties of all, astringent, with smaller fruit, ideal for colder gardens.

For a true-to-type harvest, kakis are grafted, usually onto Diospyros lotus as a hardy rootstock. Trees grown from seed only bear after six to eight years and do not match the mother variety. So buy a grafted tree from a nursery that specialises in Mediterranean and exotic woody plants.

Common mistakes and how to avoid them

The kaki is astonishingly low-maintenance when the site is right. Diseases and pests play barely any role in the home garden. The disappointments almost always come from two directions: the wrong harvest and the wrong expectation of hardiness.

The second classic: harvested too early and then put off by the puckering taste. Give the astringent varieties the time they need. And finally hardiness: the minus figures quoted apply to established trees with matured wood, not to freshly planted young trees in their first winter. Anyone who heeds these three points harvests, after a few years of patience, one of the most unusual and sweetest fruits a garden in the DACH region can yield.