Just over 30 different species of alder tree trees live and are used by landscapist in garden areas chevvy with nourishing - poor or wet soils . Four species of alder tree are particularly cosmetic and gain ground a prominent location in a garden thanks to their attractive foliage . Depending on the accurate species , alder tree diagram grow well in U.S. Department of Agriculture hardiness zone 2 through 8 .

Types

Many wild forms of alder tree seemliness landscapes include the black or common alder ( Alnus glutinosa ) , grey-haired alder ( Alnus incana ) , Japanese alder tree ( Alnus japonica ) , lily-white alder tree ( Alnus rhobmifolia ) , Oregon or red alder ( Alnus rubra ) , Sitka alder ( Alnus sinuata ) and the thinleaf or western mountain alder ( Alnus tenuifolia ) . mutation of these species yielded more attractively colourize foliation or Sir Herbert Beerbohm Tree shapes and were choose by plantsman . Some varieties bear yellow foliage or leave-taking with profoundly burn lobes , and a few selections develop into weeping - branch trees .

Origins

Alder tree are aboriginal across the Northern Hemisphere , number between 30 to 35 species . Noteworthy alders from Europe or westerly Asia include the black or unwashed alder , gray alder , Italian alder tree ( Alnus cordata ) and the greenish alder tree ( Alnus viridis ) , which is a very belittled tree at comfortably . From extreme eastern Asia hails the Nipponese alder . Western area of North America find the white alder , Oregon or red alder , Sitka alder and the thinleaf or westerly mountain alder . The minor - sized easterly mass alder ( Alnus viridis subsp . crispa ) is native to the eastern half of the continent .

Features

All species of alder trees bear leaf that are arranged alternately on the twigs . The leaf sword are typically average to deep green , entire and oval - regulate with teeth on the edges . In spring male- and female - gendered catkins , pendant swag clusters of apetalous heyday , appear on different branches on the same tree . Pollinated by the wind , the distaff catkin then develop in woody , strobilus - comparable yield that twist browned in fall and persist on the barren branches across winter . Little if any pin leaf coloring material develop before they overlook off .

Growing Considerations

alder tree tree thrive in full Sunday exposures where they receive at least eight hour of unmediated sunlight day by day . They farm considerably in passably fertile soil , acidic to alkaline in pH , that are moist but well draining . A key cultural plus of alder tree is the tolerances to both somewhat nutritionally poor grease and those that flood or stay on miry after rains . Italian and gray alder mature excellently in dry grease . If needed , prune Tree now after their leave-taking drop out in fall , but before midwinter .

Uses

The power of alder trees to acquire in rather bleak or tight soil conditions affords their use in compendious urban soils , to revegetate strip mines or other marginal area with pitiable , disturbed soils . Oregon alder , some ornate multifariousness of the black alder tree , gray alder and Alnus glutinosa bear highly attractive leafage and warrant use as shade trees . Fast - raise metal money like gray , Oregon and Italian alders make superb windbreak rows .

Concerns

Phytophthora root rot is a common fungal disease impose alder tree Tree , and if acquire with short sunlight levels , mealybug plague may arise .

References

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