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Thinleaf alder

The Thinleaf alder (Alnus incana subsp. tenuifolia)

is a tall fully hardy perennial deciduous tree/shrub with purple flowers in early Spring. It requires high levels of water. This plant requires a minimum of 130 frost free days to grow successfully. It has low drought tolerance.


Alnus incana subsp. tenuifolia grows in soils ranging from a pH of 5.5 (very acidic ranges from 5.2 to 5.5) to 7 (neutral ranges from 6.6 to 7.5). It is adapted to silt, sand, loam, clay loam, silt loam, sandy loam, loamy sand, silty clay loam and sandy clay loam soils, and prefers medium fertility.


This is a erect tree/shrub has a fast rate of growth and has a thicket forming growth form, and has an ultimate height of 9.1m / 29.9ft. The vegetative spread rate is slow.

Height at ...

  • 20 years 9.1m / 29.9ft


The leaves are green in Summer.


Hedge (medium).


Resistant to fire.

Fruit and seed

There is a high fruit/seed abundance beginning in Summer and ending in Autumn.

Progagation and germination

Propagation techniques include bare root, container and seed. The seed can be germinated by cold stratification / cold moist prechilling.

-33°C / -27.4F 5.5 to 7 9.1m / 29.9ft
Scientific classifications [Edit]
Genus ? Alnus
Specific epithet ? incana
Subspecies ?tenuifolia
Common names
Thinleaf alder (United States)
IPNI details on Alnus incana subsp. tenuifolia
References [edit] ?

Plant added by plantdatabase

Alnus incana subsp. tenuifolia http://plantdatabase.co.uk/Alnus_incana_subsp_tenuifolia
© Plant Database Ltd., 21st April 2014     Web: http://plantdatabase.co.uk     Email: mail@plantdatabase.co.uk
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