Elm is a genus of coniferous deciduous trees from the Ulmaceae family. The genus includes about 40 species of trees, most of which have simple, double-serrated leaves that grow on short petioles. The flowers are mostly bisexual, reddish in color and bloom before leafing, clustered in panicles. The fruit of the elm is a one-seeded, flat, oval or round fruit. It ripens at the end of May.
Elm grows naturally in Central and Southern Europe, and is also found in the temperate zone of Asia and Africa. In Croatia, it is an important member of lowland forests where it grows alongside ash and oak trees. The inner part of elm bark is used for medicinal purposes, and elm wood is used in shipbuilding.
Types of elm
Most of the species are distributed in the temperate zone of the northern hemisphere, and the following elm species grow in Croatia.
Siberian elm
Siberian elm (lat. Ulmus pumila L.) is a deciduous tree that can reach a height of three to 20 meters. It forms a round dense crown, and the trunk can be up to 80 centimeters wide in diameter. The bark is initially smooth and dark gray, and later becomes longitudinally cracked. Siberian elm has thin, hairy or bare branches. Its leaves are arranged alternately and have an oval-elliptic shape. They can be 3 to 7 cm long and 2 to 3 cm wide. They are leathery and have jagged edges and grow on stalks 4 to 6 millimeters long. It blooms during February and March. The fruit is an oval-shaped scale in the center of which there is a seed surrounded by a wing, and it ripens in April and May.
The natural habitat of the Siberian elm is the area of Central and Eastern Asia, and it is grown as an ornamental plant all over the world. In some parts of Central and North America, it has spread so much that in some places it is considered an invasive species.
Siberian elm is propagated by seed, grows quickly and can live up to 150 years. It can be pruned and is resistant to drought, low temperatures and urban pollution. Sunny or semi-shady places are suitable for its cultivation, and it has no special requirements regarding the type and quality of the soil.
Mountain elm
Mountain or smooth elm (lat. Ulmus glabra) can grow up to 30 meters, forming a dense canopy. It has a shallow but well-developed root system. The bark of this tree is light to dark brown in color, in young trees it is smooth, and in older trees it is furrowed longitudinally and transversely. Young brown or red-brown shoots are covered with light brown lenticels and dense hairs.
The simple leaves of the mountain elm are arranged alternately, have an asymmetrical base and an inverted egg shape. They can be up to 15 centimeters long and up to 10 centimeters wide. They are rough and jagged, and they taper slightly at the top. They grow on short stalks, and before falling in autumn, they turn yellow.
The flowers are bisexual and grow on last year’s branches, collected in dense spherical inflorescences. The inflorescence consists of leaves that can be green to reddish shades. The flowers appear before the leaves, i.e. in March and April. The fruit of the mountain elm is a winged scale located on a short stem, and can be up to 2.5 centimeters in size. It ripens during April and May.
Mountain elm is a good honey plant. It is naturally distributed in western and southern Europe and in southwestern Asia and the Caucasus. It grows in mixed deciduous forests in the hill and mountain belt up to 1500 m above sea level, and along the edges of forests, near beech, hornbeam or mountain maple.
There are several mountain elm cultivars, and the following stand out in particular:
- Camperdownii – a cultivar with a round crown and bent branches and twigs;
- Cornuta – a cultivar with broadly ovate leaves that have interesting protrusions on the upper part;
- Crispa – cultivar of low growth, with serrated leaves;
- Exoniensis – a cultivar with a narrowly conical and compact crown;
- Pendula – a cultivar with horizontally placed basic branches, while the other branches are bent and long.
Mountain elm reproduces by seed, grows quickly and can live up to 400 years. It is often grown as an ornamental tree, in small groups or separately, and deep, fertile and fresh soils are suitable for cultivation. It is resistant to urban pollution and tolerates pruning well.
Lowland or field elm
Lowland or ordinary elm (lat. Ulmus minor Mill) can grow up to 30 meters in height, has a strong and well-developed root system and a wide and dense crown, and the trunk can be up to two meters wide in diameter. The bark of the tree is thick and reddish-brown, in young trees it is smooth, and in older trees it is deeply furrowed.
The leaves of the lowland or field elm are arranged in two rows, have an elliptical or oval shape and an asymmetrical base. They are bare on the face, shiny and dark green in color, while their reverse side is slightly lighter and hairy. The flowers are bisexual and grow densely clustered in groups of 15 to 20 flowers. They appear before leafing, that is, in March and April. The fruit is a winged nut that hangs on a short stem and ripens in May and June.
Polish elm grows in Central, Southern and Western Europe, North Africa and Asia Minor. It prefers sunny places and fertile, deep and acidic, dry or fresh humus soils. It grows most often in the lowlands, and can also be found in hilly areas, along with beech, hornbeam, mountain maple, chub and alder oak trees. It can live up to 500 years, and reproduces by seed and vegetatively.
Turkestan elm
The Turkestan elm can be up to 20 meters high, and its trunk can be up to 60 centimeters wide in diameter. It has a round crown made up of thin and hanging branches. The buds of the Turkestan elm are round and dark brown in color. The leaves are oval-lanceolate and have coarsely serrated edges and pointed tips. They are located in two rows, and grow on stalks that can be from 3 to 10 millimeters long. The Turkestan elm flowers in February and March, and its fruit is a round scale containing a seed surrounded by a notched, smooth wing.
Turkestan elm does not grow wild in nature, but is exclusively cultivated as a decorative plant. It arrived in Croatia in the first half of the 20th century, via Italy, and is most abundant around Šibenik, Zadar, Split and further south. It is resistant to frost and urban pollution, it grows quickly and tolerates pruning, and it does not have any special conditions when it comes to the soil.
Embroidery or flickering elm
Twinkling elm (lat. Ulmus laevis Pall.) can be up to 30 meters high, has a deep and well-developed root, and forms an irregular, branched, wide and airy canopy. The trunk of an elm can be up to one and a half meters wide in diameter. The bark of the tree is about 2 centimeters thick and gray-brown in color. Over time, it begins to peel off into thin and narrow flat scales.
The pointed buds are covered with dark brown scales, and the lateral ones are almost the same size as the top buds. Round to narrowly ovate leaves are arranged alternately and have an asymmetrical base and pointed tips. They can be up to 15 cm long and up to 9 cm wide. They are shiny and dark green in color, smooth on the face, and covered with fewer hairs on the reverse side. They grow on stems 5 to 10 millimeters long. The flowers of the elm are bisexual and drooping, and they grow together in spherical inflorescences. The embroidery elm blooms before leafing, in March and April. Its fruits are one-seeded, hairy nuts that ripen during May.
The natural habitats of elms are mountain and lowland forests and forest edges. It grows on basic, nutritious and very moist sandy and clay soils, and sometimes on flooded soils. It is propagated by seeds and vegetatively, and is planted in alleys and parks as an ornamental tree. It is resistant to frost and its lifespan is up to 400 years, and fertile and fresh soils are suitable for cultivation.
Elm planting
For planting elm, you should choose fertile and well-drained soil and positions that receive a lot of sunlight. Elm planting next to sidewalks, terraces, parking lots or near residential buildings and any pipes should be avoided because of its roots.
Seedlings are best planted during spring or late autumn. It is not necessary to improve the quality of the soil before planting, unless it is a very poor soil. In this case, a smaller amount of compost can be added. Seedlings are planted in shallow holes that should be 7 to 10 centimeters wider than the containers in which the seedlings were grown. After that, the holes are filled with earth, without excessive compaction, and the seedlings are abundantly watered.
Cultivation and maintenance of elms
Immediately after planting, the soil around the seedlings should be mulched. Mulch will help maintain soil moisture and prevent weed growth. You can place a 5 cm thick layer of leaves, pine needles or tree bark around the seedlings. Young trees should be watered once a week, if there is not enough rainfall. It is best to water the elm by placing the water hose a few centimeters below the soil surface and letting the water flow as slowly as possible for about an hour. When the trees are strong, they should be watered only during longer dry periods.
You can fertilize young trees once or twice a year, but do not overdo it as this could harm the trees. If you grow an elm in a lawn, be careful when mowing and do not get too close to the tree to avoid damaging the roots.
Elm trees need to be pruned occasionally, but it is important that this is done at the right time, otherwise they will be more susceptible to diseases and pest attacks. The best time for pruning is early spring, while you should definitely not do it during autumn or between April and July. You can remove dried and diseased branches at any time.
Diseases and pests
One of the most significant diseases that can appear on these trees is the Dutch elm disease. This devastating disease led to the decline of millions of trees in Europe and the USA in the 1900s, and is caused by three species of fungi from the genus Ophiostoma. The disease is spread by bark beetles, and the first symptoms of the disease are drying and yellowing of the upper branches on the tree and curling of the leaves in the summer months. The infection slowly spreads to the rest of the tree, causing the branches to die over time. To prevent this problem, it is recommended to grow more resistant cultivars.
Application of elm
Elm wood is used in carpentry, carving and shipbuilding. It is somewhat more difficult to machine, but it is excellent for turning. After drying, elm takes on a slightly darker color, and its durability is approximately 12 years. It is also used for the production of parquet and massive furniture. Elm bark is used in folk medicine to make preparations to stop bleeding and stimulate urination and sweating.
White-leaved trees
Elm is one of the numerous types of coniferous trees. What all species have in common is that their leaves, which appear in the spring months, change color from green shades to warm red, yellow, orange or brown tones during autumn. Considering that the leaves fall from the trees before winter, we also call this type of trees deciduous trees.
Deciduous or deciduous trees differ in the height they can reach, the bark of the tree, the shape of the crown, the shape of the leaves, the type of roots, the appearance of fruits and flowers, etc. Most of these trees bloom in the spring with fragrant flowers that attract insects and thus pollinate. Fruits develop from the pollinated flowers, which are edible in some types of conifer trees, but not in others.
In addition to elm, the most common species in our area are holm oak and cypress, poplar, wild chestnut, hornbeam, ash, linden, elder, acacia, wild cherry, apple, sycamore, hazel, sweet chestnut, maple, alder, birch, willow. and various fruit trees.
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