General Description

Ulmus laevis is a medium to large sized, broad spreading tree with small to medium sized green leaves forming a rounded, open crown.

Landscape

Once a popular landscape tree in Europe and North America, U. laevis has seen a dramatic fall in economic value and usage over the last few centuries. This is largely due to Dutch elm disease that became problematic during the 20th century and resulted in most elm species in the landscape being replaced with other genera. Although in the past the wood of the European white elm was used in production and trade, in modern day its wood is considered useless as the cross-grained lumber causes mechanical errors in manufacturing. Today this species is mostly planted along roadsides due to its tolerance of salts, pollution, and soil compaction. It sometimes can be used as a hedge when “field clonal archives” (Collin, E. p.4) maintained accordingly. The early springtime bloom of the European white elm can be attractive and beneficial for butterflies so it can also be used in the landscape to promote butterfly populations. Other landscape uses of U. laevis today may include shade tree or park plantings, and occasional ornamental/specimen planting.

Cultivation

This tree thrives in full sun with moist soil conditions in areas of 300 m altitude or lower. It is an elm species particularly sensitive to heavy winds, so if planted in open areas it may be necessary to plant windbreak species around the area as well. U. laevis can tolerate moderately dry conditions, salt, soil compaction, and pollution.

Shape

It can be a single or multi stemmed tree with horizontal branching that begins with an open oval shaped crown that becomes more rounded with maturity. This species of elm is less uniform looking than the other European elm species and tends to have looser, more unpredictable branching patterns.

Growth

Fast

ID Characteristic

The characteristics of red clustered flowers attached to long green pedicels, fringed green samaras, and tomentose undersides of the leaves that give the appearance of white colour, distinguish this species from other trees.

Pests

Dutch elm disease has majorly impacted Elms. It is a disease derived from two introduced fungal pathogens, Ophiostoma novo-ulmi and Ophiostoma ulmi. These pathogens are spread by two species of Scolytus (elm bark beetle), Scolytus schevyrewi (banded elm bark beetle), and Scolytus scolytus (large elm bark beetle). Dutch elm disease can cause yellowing and eventual dropping of the leaves, as well as wilting and necrosis of the branch and stem tissues. In the 20th century, more than half of the entire elm populations of eastern and central Europe had been affected by this disease; however, out of the three European native elm species, U. laevis was the least affected. This is believed to be due to the Scolytus sp. preference for the other Ulmus species. Other pests and diseases that can affect U. laevis include nun moth, elm black spot, elm zigzag sawfly, and elm yellows.

Habitat

In nature, Ulmus laevis is most commonly found growing in riparian deciduous forests, near floodplains in areas at an altitude of no more than 300 m. Natural populations of U. laevis are also found in mixed deciduous forests and transitional zones between grasslands and woodlands.

Bark/Stem Description

The bark is a brownish-grey colour that starts out smooth and begins to develop intersecting vertical fissures as the tree matures. These fissures are not very deep and can resemble scales. Well into its maturity, it can develop deeper and more scale like plates and begin to reveal patches of rusty brown bark in the fissures. This species of elm can also develop buttress roots at the base of the trunk, giving the tree a fluted appearance. The branching is alternate and horizontal. The young branches are smooth with more of a brownish-green colour that begins to bear more resemblance to the trunk as they mature.

Flower/Leaf Bud Description

The buds are ovate shaped and can measure up to 2 cm in length. They can be identified through the characteristic bud scales that are sharply pointed at the apex, and the rusty brown colour. As the leaf buds grow the scales will be elongated and fade into a light green. The winter leaf buds tend to be longer and more sharply pointed than the springtime buds which may be shorter and wider.

Leaf Description

Leaves are simple, stipulate leaves with pinnate venation and a bright green colour that transitions to yellow in autumn. They are attached to branches by petioles about 1 cm in length. The leaves can be identified by their oblique bases, having a rounded shape on one side of the midrib and a tapered off, thinner shape on the other. The overall leaf shape is ovate with an acuminate apex and doubly serrate leaf margins, usually measuring no more than 5 cm long and 3 cm wide. They feel similar in touch to paper, with tomentose undersides that give the appearance of white colour and a soft feeling on the undersides of the leaves.

Flower Description

In March and April, the European white elm produces clusters of purplish-red blooms attached to peduncles by long, green pedicels measuring up to 2 cm in length. The flowers are usually perfect flowers containing 5-9 stamens and one appressed pistil with two small, white, stigmata. At the base of each flower is the purplish-red coloured calyx made of sepals fused together in which the pistil is contained, and the stamens protrude. It is an anemophilous tree that is pollinated by the wind and also allogamous, which will not cross pollinate with other elm species.

Fruit Description

The flowers are dense clusters of ovate samaras reaching a length of about 1 cm with two points at the apex that curve inwards. They are usually pedunculate and are attached to peduncles by long, brown, pendulous pedicels and develop in the spring after the flowers develop. These samaras are ciliate, giving the appearance of fuzzy or winged margins, and are a soft green colour at full maturity. Each samara of the European white elm contains one smooth, dark brown seed which sits closer to the base of the samara and has a diameter of around 5 mm. When ripe, the samaras become dry, more of a brown colour and will fall from the tree. The time in which these fruits develop and ripen is dependent on the weather patterns but will typically begin falling from the tree in late March or April.

Colour Description

The foliage is green that transitions to yellow in autumn, attached to branches by short, green coloured petioles. This species has brownish-grey bark with young branches that are more of a greenish-brown colour. The flower blooms of this species are purplish-red with green pedicels and the fruit are a soft green.

Texture Description

The European white elm is a fast growing, medium textured tree that appears finer textured in its leafless season. The loose crown shape results in a less dense looking tree but is still fairly filled out when it has its foliage. In winter when there is no foliage and in spring when its non-uniform branches are covered in very delicate and finely detailed flowers, the lack of leaves allows for increased light reflection and gives a fine textured appearance.

Notable Specimens

One of the largest elms in all of Europe, known as the Weidzmin (Witch) is a specimen of Ulmus laevis. The Weidzmin is located in Komorow, Lubusz Voivodeship, Poland and is approximately 470 years old. This specimen was officially named a Polish national monument in 1971 and has had a fence put up around it in order to preserve it.

Propagation

It can be propagated by seed as well as cuttings. The seeds should be harvested from the tree when fully ripe in April or taken from the area around the tree after they’ve fallen; samaras surrounding the seeds should be removed. Stratification at 4°C for 2-3 months can increase speed and likelihood of successful germination. Seeds should be planted in a universal germination medium in summer and kept consistently moist at a temperature of 25°C - 30°C. Ulmus laevis seeds can germinate in darkness or with access to moderate amounts of light each day (8-12 hours). If given proper conditions seeds should sprout within 2-4 weeks of planting. In winter, semi-hardwood cuttings from branches can be taken from U. laevis to be propagated. These cuttings can be planted in a universal growing medium, perlite or vermiculite, and should be kept consistently moist at a temperature of 18°C - 20°C. Applying indolebutyric acid, a form of rooting hormone, to the cut area can increase successful propagation of woody cuttings. If given the proper conditions stem cuttings should take root within 8-12 weeks of planting.

Ethnobotanical Uses (Disclaimer)

In the past the European white elm was used as a source of timber for building items like pallets and crates and its bark was used as binding material for books, shoes and hats. It has been and continues to be planted in landscapes to mitigate soil erosion in areas with particularly high amounts of rainfall, as well as to improve soil stabilization and reforestation. Today, the wood is not used often even for firewood as it is of poor quality. It is sometimes planted as an ornamental for its semi-attractive spring bloom but is most commonly used in roadside, naturalization, and urban plantings.

Bonner, F. T., Karrfalt, R. P., Barbour, J. R., & Brinkman, K. A. (2008). Ulmus L. In The Woody Plant Seed Manual (pp. 1143–1149). U.S. Dept. of Agriculture, Forest Service. Venturas, M., Fuentes-Utrilla, P., Ennos, R., Collada, C., & Gil, L. (2013). Human-induced changes on fine-scale genetic structure in Ulmus laevis pallas wetland forests at its SW distribution limit. Plant Ecology, 214(2), 317+. Accessed November 6, 2021, from, https://link.gale.com/apps/doc/A335825588/PPGL?u=ko_acd_fc&sid=bookmark-PPGL&xid=b2371582