general characteristics
- the alder is a deciduous tree
- summer green
- deep green color
- often ovoid
Characteristics of the leaves of different species of alder
Alnus company alder
- 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 margin
Gray alder
- ovoid
- tapering to a point
- The leaf margin is coarse and double serrated
- gray, felty hairs on the underside of the leaf
- up to 10 cm long
Purple alder
- large-leaved
- runs to a point
- dark green
- ovoid
- The underside of the leaf is very dull, lighter than the upper side of the leaf
- sawn leaf edge
Heart-leaved alder
- comparatively small
- Leaf margin is slightly serrated
- dark green
- asymmetrical
Red alder
- ovoid
- runs 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 to which the alder gives a breeding ground, while the bacteria supply the tree with nitrogen compounds so that it can also grow on nutrient-poor soils succeed. Alder trees are therefore also referred to as pioneer trees because they have adapted in this way to locations in inhospitable locations. Furthermore, alders provide a source of food and a habitat for numerous butterfly species.
also read
- When does the alder bloom?
- The blossom of the alder
- Learning to identify the leaves of the elm
Evidence of diseases
So don't be surprised if you find green foliage under your alder. This is not a sign of illness. However, you should pay attention if the leaves become unusually light and have a yellowish discoloration. In addition, the tree forms only very small or no new leaves at all if a fungus infests. Old leaves are also thrown off prematurely. If you observe these symptoms, it is likely that the alder is dying.