Wych elm

Family

Ulmaceae

Habit

Tree

Height

32.5 m

Spread

24 m

Growth

fast

Lifespan

400 years

First yield

after 30 years

Hardiness

zone 5–8

Shade tolerance

partial shade

Soil

Silt, Loam, Clay

Soil moisture

semi-dry – very wet

pH

5.5 – 8

Synonyms

Ulme

Times apply to the northern hemisphere in a temperate climate and shift with altitude and cultivar.

Edible: Leaves can be consumed either in their raw form or cooked, offering a slightly bitter taste, particularly as they mature, along with a slimy texture. They make a great addition to mixed salads. The unripe fruits, when used right after forming, can also be eaten raw, providing a unique aromatic flavor that leaves a refreshing sensation and pleasant scent. The fruits are approximately 2.5 cm in length, with a mucilaginous inner rind that is commonly dried, ground into a powder, and combined with grains to thicken soups or bread. They have a nutritional composition of about 34.4% protein, 28.2% fat, 17% carbohydrates, and 5% ash.

Medicinal: The plant's inner bark possesses astringent, soothing, and mildly diuretic qualities. It is utilized for various purposes such as treating diarrhea, rheumatism, wounds, hemorrhoids, and other conditions. Additionally, it serves as a mouthwash for ulcers. Harvested from 3-4 year-old twigs, the inner bark is dried for use. In Bach flower therapy, this plant is employed to address emotions of inadequacy, discouragement, and fatigue resulting from an overly zealous quest for perfection. Furthermore, a homeopathic remedy derived from the inner bark is administered for eczema treatment.

Other uses: Wych elm timber is tough, elastic, hard and abrasion-resistant, and has the rare property of barely rotting under water. For centuries it was therefore made into water pipes, well casings, ships' keels and harbour piles. Wherever toughness was wanted, elm was the first choice: cartwheels and hubs, hammer handles, chair seats, flails. Furniture makers still prize its lively grain. The bast of the inner bark yields mats, ropes and cord. Pollarded shoots give firewood, charcoal and fence posts, and the foliage was cut as fodder for livestock. Because Dutch elm disease has made large healthy wych elms rare, the timber now has little commercial importance.

Site: What matters is not the soil but Dutch elm disease. The ascomycete Ophiostoma ulmi blocks the water-conducting vessels and is carried by the elm bark beetle, which breeds in weakened elms; if diseased or dead old elms stand nearby, a new planting is close to hopeless. Check this before planting and otherwise choose a resistant hybrid cultivar. Infection is favoured by drought stress, close planting and a lowered water table — precisely the conditions a cramped site creates. The wych elm reaches 30 to 40 metres and casts dense shade under which little will grow, so it needs room. It almost never suckers. It flowers wind-pollinated in March before leaf burst, which makes it a poor neighbour to seating areas for anyone sensitive to pollen. Care: Water young trees through their first summers, since drought stress is the disease's way in. Prune as little as possible and only in winter: open wounds attract the bark beetles, which fly from April to September. Elm wood must not be stored with the bark on, as it then serves the beetles as breeding material — strip or burn it, and remove infected branches at once. The species coppices strongly and tolerates pollarding, which makes it useful for laid hedges and firewood (around 4.1 kWh per kilogram). Protect young plants against browsing and fraying damage. On suitable soils no extra feeding is needed.

The wych elm fruits abundantly, but its seed is awkward: the thinly winged samaras ripen as early as two months after flowering, in May, need light to germinate and stay viable only for days to weeks. Anyone sowing must therefore collect fresh and sow at once, shallow and uncovered; dried or stored seed is practically dead. One gram holds about eighty seeds. Germination follows within a few weeks and the young plants grow quickly, but they do not flower for thirty to forty years. Vegetatively the species is readily increased from coppice growth: trees cut back to the stool reshoot reliably. Cuttings root poorly, which is why nurseries graft onto seedling rootstocks — with resistant cultivars that is in any case the only way to pass the resistance on.

Despite its scarcity the wych elm carries real weight in the native food web. It flowers wind-pollinated as early as March, ahead of almost every other tree, and although it yields little nectar its pollen is one of the year's first protein sources for honeybees and early-flying solitary bees; surviving traces of nectaries and pollenkitt show that the species turned to wind pollination only late. The greater value lies in the foliage: several moths and butterflies are wholly or largely tied to elms, among them the white-letter hairstreak, the dusky-lemon sallow and the scarce umber, while comma, peppered moth and swallow-tailed moth also feed on the leaves. The samaras, ripe as early as May, are taken by seed-eating birds, and the bark crevices and cavities of old trunks by woodpeckers, bats and saproxylic beetles. Dutch elm disease has made all of this scarcer.

Special features: loves humid climates, tolerates polluted air; never forms dense stands, but only scattered in mixed forests; seeds (1g = 80 seeds) are viable for only a few weeks; sprouts well, topped shoots for firewood, coal, posts, etc.; partly on the Red List (rare); 1900 kWh/m²; 4.1 kWh/kg

Europe, from central Spain and Italy to southern Scandinavia, eastwards to the Urals and into the Caucasus. The wych elm thus occupies almost the whole continent, yet nowhere forms extensive stands, appearing instead scattered through mixed woodland. In Central Europe its stronghold is the uplands and the Alpine fringe: it climbs from the lowlands to about 1300 metres, and to 1500 metres in the Allgäu Alps. Numbers have fallen sharply for decades, since Dutch elm disease removed large old trees across the board; several German states therefore list it as threatened, even though the range itself is undiminished.

The wych elm is a tree of shaded, humid slopes. Its typical sites are ravine woodland and steep north-facing hillside forest on seepage-moist, nutrient- and base-rich loam and clay, often over block scree. In phytosociological terms it is a character species of the lime-maple ravine forests, standing alongside large-leaved lime, sycamore and ash; at higher elevations it passes into maple-beech mixed woodland. It never forms closed stands. It roots in arbuscular mycorrhiza, tolerates moderate shade and is markedly wind-firm, but reacts badly to a falling water table and to strongly acid soil. Compacted, dry urban ground does not suit it, though polluted air does it no harm.