Alnus glutinosa - Common or European Alder (Betulaceae) ------Alnus glutinosa is an underutilized shade tree that is resemble miniature pine cones are very characteristic excellent for wet or dry sites. European Alder has of Alders, and often persist into the following season glossy dark green summer foliage, a pyramidal shape Twigs and rapid growth in youth, and ornamental fruits and -green-brown to brown and smooth catkins in winter. Trunk -bark is green-brown in youth, changing to brown FEATURES and slightly ridged with maturity Form -trees can be single leader or multi-trunked, and are -large shade tree, doubling as an strongly pyramidal in youth, but more upright oval ornamental tree in youth and sometimes losing the central leader with age -maturing at 60' tall x 30' wide -upright pyramidal growth habit USAGE in youth, becoming upright oval Function or open and irregular with -shade, specimen, wet site, or deciduous windbreak maturity, sometimes losing its tree, effective in solitary, group, or linear plantings strong central leader with age, Texture and also sometimes found in -medium texture in foliage and when bare multi-trunked form -thick density in foliage and when bare -rapid to medium growth rate Assets Culture -wet site or dry site tolerant; an alternative to -full sun to partial sun Willows and Poplars for wet and difficult sites -prefers moist to wet soils of average fertility in full -rapid growth and establishment sun, but is adaptable to poor soils, dry soils, and soils -dark glossy green foliage that flutters in the breeze of various pH -can also be considered an ornamental tree in youth -sensitive to heat and drought (due to its strongly pyramidal habit, winter persistent -forms a nitrogen-fixing association with cone-like fruits, and late winter elongated catkins) microorganisms -wood more resistant to storm damage as compared -sensitive to branch cankers and tent caterpillars as to other rapidly growing landscape trees occasional minor disease and pest problems, Liabilities respectively -none serious, although branch cankers and tent -low availability, in B&B form caterpillars occasionally occur Foliage Habitat -alternate, densely -Zones 3 to 7 foliaged, and dark -Native to Europe, Western Asia, and Northern glossy green Africa leaf blades are 3" long -naturalizes along wet sites where it has escaped and x 3" wide, oval to self-propagated by seeds orbicular, doubly serrated, and distinctly SELECTIONS notched at the apex Alternates when fully expanded, -rapidly growing shade trees (Acer x freemanii, with impressed veins Betula nigra, Liquidambar styraciflua, Quercus -autumn color is acutissima, Zelkova serrata, etc.) green, yellowish- -shade trees for wet sites (Betula nigra, Celtis green, or yellow- occidentalis, Populus deltoides, Quercus bicolor, brown, and Salix alba, Taxodium distichum, etc.) ornamentally ineffective -pyramidal trees (at least in youth) (Abies fraseri, Flowers Picea abies, Liquidambar styraciflua, Quercus -monoecious (separate male and female flowers on palustris, Taxodium distichum, etc.) the same plant) Cultivars - Variants - Related species -clustered reddish-brown male catkins are present in -Alnus glutinosa 'Imperialis' - a cutleaf form, with winter, to about 1" long, but elongate up to 4" in light green leaves that have sinuses cut over halfway Mar., swaying in the early spring winds to the midrib, somewhat awkward looking in youth -miniature oval purple female flowers are barely but maturing into a fine specimen tree noticeable in Mar., without any corolla but emerging -Alnus glutinosa 'Pyramidalis' - an extremely upright with exerted pistils to accept pollen from the nearby columnar form, maturing at 40' x 10', which can be catkins used in rows as a deciduous privacy screen or Fruits individually as a distinct focal point or specimen tree; -small brown winged nutlet seeds this columnar form (actually not a pyramidal form, as are borne in green ovoid rough fruits the cultivar name implies) is a possible substitute for that are about 0.5" long, changing to the disease-prone and readily suckering Lombardy dark brown in autumn Poplar (Populus nigra 'Italica'), but unfortunately is -the winter persistent clusters of rarely available in the nursery trade opened fruits (strobiles) that