Service Tree, Wild Service Tree and Rowan: Wild Fruit for the Patient

There are trees you plant not for yourself but for your grandchildren. The service tree is one of them. It grows slowly, bears late and in return lives for centuries. Whoever plants one today is mostly giving a gift to the people who will sit in its shade fifty years from now. That is exactly what makes these three wild fruit trees so special: service tree, wild service tree and rowan are not trees for quick harvests, but for gardeners who think in decades and who love the appeal of the rare.

Three trees, one family

All three belong to the Sorbus genus in the rose family, so they are distant relatives of apple, pear and hawthorn. Despite their shared roots they look completely different. The service tree has pinnate leaves and small apple- or pear-shaped fruit. The wild service tree surprises with maple-like lobed leaves and brown, speckled berries. The rowan, also known as mountain ash, is the best known of the three with its bright orange-red clusters of fruit.

What unites them: they are native, extremely winter-hardy, heat- and drought-tolerant and therefore genuine climate trees for the decades ahead. And their fruit is edible, even though none of it is a treat straight off the tree. The detour through kitchen and time is part of the concept with this wild fruit.

The service tree: nobility among wild trees

The service tree Sorbus domestica is the aristocrat of this group. In the wild it has become so rare in Germany that individual old trees are known by name. Its wood is the heaviest and hardest native timber, once prized for vices, weaving shuttles and organ pipes. In Frankfurt and the Rheingau region the service tree lends its distinctive note to cider as an additive. A single tree can easily reach two to three hundred years of age.

For the home garden this means: you are planting a piece of living cultural history. Expect a long juvenile phase in which it only grows and sets no fruit. A grafted tree bears after about eight to ten years, a seedling happily takes fifteen years or more. In return it forgives poor, chalky and dry soils where an apple tree would long since have given up.

A full-sun, warm spot is essential. The service tree loves warmth and rewards a sheltered south-facing position with early ripening and good growth. In harsh upland locations it survives but bears unreliably. One tree is enough for a harvest, since it is self-fertile, although cross-pollination increases the yield.

The wild service tree: maple leaf and precious wood

The wild service tree Sorbus torminalis shares the title Tree of the Year 2011 with the service tree and is at least as rare. Its foliage is deceptive: the deeply lobed leaves recall a Norway maple and have nothing in common with the pinnate relatives. In autumn the leaves turn warm copper and purple tones, making the wild service tree one of the most beautiful native autumn trees.

Its wood is even more sought after than that of the service tree and ranks among the most expensive timbers in Europe, prized for veneers and musical instruments. The small, leathery brown fruit tastes surprisingly mild after bletting, almost of marzipan and dried fruit. In Austria a rare fruit brandy is distilled from it. The wild service tree thrives in similarly warm, lime-rich locations to the service tree and tolerates partial shade even better.

The rowan: the underrated mountain ash

The rowan is the counterpoint to its noble relatives: undemanding, fast-growing and at home everywhere, from the coast up to the tree line. That is precisely why it is the ideal starting point. It bears within a few years, tolerates almost any soil and flowers in May in large white umbels that magically attract wild bees. From August the orange-red clusters glow and feed more than sixty bird species through the winter.

The belief that rowan berries are poisonous persists stubbornly. That is not really true: raw, they contain parasorbic acid, which in larger quantities irritates the stomach and gut and can cause nausea. Cooking, drying or frost converts it into harmless sorbic acid. Cooked rowan berries are safe and make a wonderfully tart, bittersweet jelly.

If you would rather not bother with the kitchen, reach for the cultivated form Sorbus aucuparia 'Edulis', also called the Moravian rowan. Its berries are larger, lower in tannin and noticeably milder, so you can even nibble them raw in small amounts. For jelly, compote and liqueur it is the first choice.

From bletting to the glass: harvest and use

None of this fruit tastes good fresh from the tree. All of it needs either bletting or frost until the tannins break down and the sweetness comes through. You can tell bletting has happened when the fruit turns soft, doughy and slightly brownish, much like the medlar. Only then does the cooking begin.

1. Harvest at the right time

   Pick service tree and wild service tree in September and October, as soon as the fruit begins to soften. Harvest rowans after the first frost, or put them in the freezer overnight.

2. Let it ripen further

   Spread hard fruit out somewhere cool and airy on trays until it is soft and aromatic. Depending on ripeness this takes a few days to two weeks.

3. Juice or sieve

   Simmer the fruit until soft and pass it through a food mill, or turn it into clear juice in a steam juicer. Seeds and skins stay behind.

4. Make verjus, jelly or liqueur

   From unripe-harvested fruit you press verjus, the sour seasoning juice of the old kitchen. From ripe juice you cook jelly with preserving sugar, or steep the fruit in grain spirit or vodka to make liqueur.

The tart, sour flavour is intentional and makes these products so distinctive. A service tree jelly with game, a rowan liqueur as a digestif or a few drops of verjus in a salad dressing are culinary rarities you cannot buy in the shop. That is exactly where the appeal lies: you harvest something that hardly anyone knows.

Planting and care: location, pruning, patience

Good news for impatient gardeners: once planted, these trees are little work. They are robust, need barely any pruning and are largely immune to the usual fruit tree diseases. They are best planted as bare-root stock during the dormant season between October and March, on a frost-free day.

1. Choose the location

   Full sun and warmth for service tree and wild service tree, while the rowan will also take partial shade. Plan for enough space, all three can grow large.

2. Dig a generous planting hole

   Twice as wide as the root ball, loosen the base. On heavy soil work in a little sand, but no fresh manure.

3. Set the tree and water it

   Keep the graft union above the soil, slurry the soil in, form a watering rim and water thoroughly. Add a stake against wind-throw.

4. Support it through the first years

   Water during dry spells in the first two seasons and mulch the tree base. After that the trees look after themselves.

A formative prune in the first years builds a stable crown, after which it is enough to remove dead and rubbing wood. Here, less is more. Whoever gives these trees time is rewarded with decades of harvest, with shade, with autumn colour and with the quiet pride of preserving something rare.