The alder has a great diversity of species. In Germany, however, there are only three varieties. Could you tell the common alder from its relatives, the green alder or the gray alder, by its leaves? In the case of non-native species, the distinction is probably even more difficult. Don't worry, in the following article you can read all about the characteristics of the different alder species. In addition, you will learn about other properties that characterize the deciduous tree.

The alder has juicy green, slightly rounded leaves

general characteristics

  • the alder is a deciduous tree
  • deciduous
  • rich green color
  • often ovate

Features of the leaves of different alder species

Alnus company Erle

  • sawn leaf edge
  • ovoid
  • green
  • fixed
  • protruding spikes on the edge of the leaf

Oriental Alder

  • obovate
  • long petiole
  • green
  • small indentations in the leaf margin
  • wavy leaf edge

Gray Alder

  • ovoid
  • tapering
  • Leaf margin is coarse and doubly serrated
  • grey, felty hairs on the underside of the leaf
  • up to 10 cm long

purple alder

  • large-leaved
  • tapers to a point
  • dark green
  • ovoid
  • Underside of leaf very dull, lighter than upper surface of leaf
  • sawn leaf edge

Heartleaf Alder

  • comparatively small
  • Leaf margin is slightly serrated
  • dark green
  • asymmetrical

Red alder

  • ovoid
  • tapers to a point
  • about 15 cm long
  • alternate leaf position
  • sawn leaf edge

particularities

Did you know that the alder is the only deciduous tree that sheds its leaves when green? This is possible because alders enter into a symbiosis with so-called root nodules. These are bacteria that the alder provides a breeding ground for, while the bacteria supply the tree with nitrogen compounds so that it can grow successfully even on nutrient-poor soil. Alders are therefore also referred to as pioneer trees because in this way they have adapted to locations in inhospitable locations. Furthermore, alder trees provide a food source and habitat for numerous species of butterflies.

indications of diseases

So don't be surprised if you find green leaves under your alder. This is not a sign of illness. However, you should be alert if the leaves are unusually light and have a yellowish discoloration. In addition, the tree develops only very small or no new leaves in the event of a fungal infestation. Old leaves are also shed prematurely. If you observe these symptoms, it is probably due to alder dieback.

Category:

Trees