A larch is a deciduous conifer. Its autumnal display of yellow, gold or orange needles makes it not only particularly attractive but also hardier than other conifers. The tree is bare during the winter and hence the needles cannot get damaged by extreme cold.
The needles of larches, which grow in dense clusters, are soft, not sharp or spiny like other conifers.
The Larix genus comprises ten different species with many cultivars, and several cross-bred hybrids between two species. Plus, there are about a dozen species that are not unanimously recognized as separate species by botanists.
Larches vary in their needles and twig shape and size. They can have pyramidal or weeping habits. What all larches have in common is that they are a hardy tree.
|Botanical Name||Larix spp.|
|Plant Type||Deciduous tree|
|Mature Size||40 to 100 feet height, 20 to 30 feet width|
|Sun Exposure||Full sun|
|Soil Type||Silt, clay, loamy|
|Soil pH||5.0 to 7.5|
|Hardiness Zones||2-7 depending on species|
|Native Area||Northern hemisphere|
Larch Tree Care
If given ample moisture, larch trees are undemanding to grow. The one big exception is that they won’t do well in places with high air pollution.
The size of larch trees varies greatly, so if you have your mind set on planting one, make sure to pick a species or cultivar whose mature size is appropriate for your yard.
Depending on the species, the tree might require annual pruning.
Most larch species require full sun but some can tolerate partial shade.
Except for dry soil, larch trees are highly adaptable to different types of soil.
In their natural habitat, they often grow in bogs where the soil contains very little to no oxygen—the soil pores are filled with water instead of air. Any wet, peat-rich soil that mimics that environment is a good location.
Larch trees need ample moisture and won’t tolerate drought. The trees even do well in locations with temporary flooding.
Especially during the first two years after planting until the tree is established, make sure that that soil is consistently moist and never dries out.
Temperature and Humidity
Larches are hardy trees that are well adapted to cool climates. They can withstand humidity during the summer, however, they don’t tolerate hot, dry climates.
Newly planted larch trees, however, should not be fertilized during their first growing season or two.
Larch Species and Varieties
Popular larch species and varieties include:
- European larch or common larch (Larix decidua) has a mature size of 100 feet in height and 20 to 30 feet in width. There are two popular smaller cultivars: the weeping larch, Larix decidua ‘Pendula’, that only grows 10 to 12 feet tall, and the contorted European larch, Larix decidua ‘Horstmann’s Recurved’ with twisting, curving branches. It is slow-growing to a height of only 4.5 to 7.5 feet and a width of only 3 to 4 feet at maturity.
- Japanese larch (Larix kaempferi) has a mature size of 70 to 90 feet in height and 25 to 40 feet in width. Here, too, smaller cultivars are available: the weeping larch, Larix kaempferi ‘Pendula', the contorted cultivar ‘Diana’, and ‘Blue Dwarf’ with bluish foliage.
- Eastern larch, American larch, or Tamarack larch (Larix laricina) reaches 40 to 80 feet in height and 30 to 50 feet in width at maturity, The tree is native to most of northern North America. A smaller cultivar is the globe-shaped Larix laricina ‘Blue Sparkler’ that only reaches 12 feet in height and 3 feet in width.
- Subalpine larch, Alpine larch, or Lyall larch, (Larix lyallii) can grow as tall as 80 feet. It is native to northwestern North America and is an important tree for native wildlife. Birds such as the blue grouse, as well as mammals such as mountain goat, feed on its needles.
- Siberian larch or Russian larch (Larix sibirica) reaches 80 to 200 feet at maturity. It is native to western Russia and Siberia.
- Western larch (Laris occidentalis) can grow up to 150 feet tall. It is native to the northwestern mountains of the United States and has a high wildlife value, as it serves as the host for nest-building animals.
- Dahurian larch (Larix gmelinii) reaches 40 to 90 feet in height and 15 to 30 feet in width at maturity. It is native to northeastern Siberia, Mongolia, and northeastern China. There are four varieties that originate in different areas and have different needles; one of them is the Japanese variety Larix gmelinii var. japonica.
Growing Larch in Containers
Larch trees make attractive bonsai. The two species commonly grown as bonsai trees are European larch (Larix decidua) and Japanese larch (Larix kaempferi).
The most common disease of larch trees is larch needle cast, which is also called Meria needle cast. It is a fungus that is triggered by wet conditions in the spring. It starts with brown spots on the needles and gradually moves towards their base. The brown needles drop prematurely. The best line of defense is to make sure the tree is from a nursery where the disease is not present.
Damage from the larch casebearer, a European moth, starts with tiny caterpillars invading the needles. Later the larvae feed on needles. The needle tips may appear scorched or, if the infestation is heavy, the tree can be completely defoliated.
Fortunately, the populations of the larch casebearer are usually kept in check by cold and wet spring weather and late frosts, as well as by naturally occurring predators such as birds and parasitoids wasps that were introduced for biological control of the pest.