eastern hemlock

(Tsuga canadensis)

Conservation Status
eastern hemlock
Photo by Randy
  IUCN Red List

NT - Near Threatened

     
  NatureServe

N5 - Secure

S3 - Vulnerable

     
  Minnesota

Endangered

     
           
Wetland Indicator Status
     
  Midwest

FACU - Facultative upland

     
  Northcentral & Northeast

FACU - Facultative upland

     
           
 
Description
 
 

Eastern hemlock is a slow growing, long-lived, medium-sized, coniferous tree. It rises on a single trunk from a shallow, wide spreading root system. In Minnesota mature trees are usually 40 to 60 tall and up to 24 in diameter at breast height. In other areas individuals can reach 98 in height and 40 in diameter.

The trunk is tapered, straight, and distinct to the top of the tree. The crown on younger trees is dense and broadly cone shaped. The slender leading shoot at the tip of the crown droops in the direction of the prevailing wind in the spring, but usually straightens out later in the year. On older trees the crown is uneven and the branches are irregularly spaced.

The branches are slender and horizontally spreading with drooping tips. Dead branches remain on the lower trunk for years.

The bark on young trees is reddish-brown to purplish-brown; thin; and broken into thin, roundish or irregular scales. On mature trees the bark is reddish-brown to gray and thicker. The scales are thicker and are broken into vertical ridges and furrows. On older trees the bark is thick with deep furrows. The ridges are often broken horizontally into irregular blocks. On mature and older trees newly exposed bark is reddish-purple.

First year twigs are greenish- or yellowish-brown and densely hairy. Older twigs are brown or grayish-brown and hairless. The twigs are slender and flexible. They are rough to the touch due to a forward-pointing, peg-like projection at the base of each leaf that persists after the leaf has fallen. Side branches on the twigs are arranged on a flat plain.

The buds are egg shaped, rounded at the tip, reddish-brown, non-resionous, hairy, and 1 16 to long. The leaf scars are raised, forward facing, rough, and reddish brown.

The needle-like leaves are alternate and evergreen, remaining on the twig about 3 years. They are attached to the twig on a short, thread-like stalk (petiole). The petiole is twisted or bent causing the leaves to appear two-ranked. Each leaf is linear, flat, flexible, and to ¾ long. Unlike a spruce leaf, it will not roll easily between thumb and forefinger. It is rounded at the tip and at the base. The upper surface is shiny and dark green. The lower surface is similar but with a row of tightly-spaced white dots on each side of the midrib. Each white dot (stomate) is a pore surrounded by two glaucous guard cells. When crushed, the leaves emit an odor similar to the herbaceous species hemlock (Conium).

Male and female flowers are borne on the same tree. Pollen (male) cones arise from clusters of yellow flowers in the lower part on the crown. They rise at the end on a greenish-white scaly stalk from leaf axils near the end of second-year branchlets. The cones are globe shaped, yellow, and about in diameter at maturity. In Minnesota they shed pollen in May or early June, about two weeks after leaf buds burst.

Female cones hang downwards singly at the tips of second-year branchlets in the upper part of the crown. They are to ¾ long, ellipse shaped when closed, egg-shaped when open. The scales are thin, egg-shaped to wedge-shaped, 5 16 to ½ long, and ¼ to wide. They are rounded at the tip and project outward. Female cones reach full size in late August to early September, open in mid-October, and remain on the tree for more than a year.

The seeds are small and have large wings. Seeds are dispersed throughout the winter.

 
     
 

Height

 
 

40 to 60

 
     
 

Record

 
 

There are two co-champion eastern hemlocks in Minnesota.

The first is on private public near Minneapolis, in Hennepin County. In 2018 it was measured at 74 tall and 87 in circumference (27¾ in diameter).

The second is on private property near Cottage Grove, in Washington County. In 2019 it was measured at 65 tall and 100 in circumference (31¾ in diameter).

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

Moist, rich, acidic, well drained soil. Mixed forests. Partial shade to partial sun—very shade tolerant.

 
     
 
Biology
 
 

Pollination

 
 

May or early June

 
     
 

Pests and Diseases

 
 

Hemlock woolly adelgid (Adelges tsugae)

 
     
 
Use
 
 

 

 
     
 
Distribution
 
 

Distribution Map

 

Sources: 2, 3, 4, 5, 6, 7, 8, 24, 28.

The sighting in Crow Wing County is at the Northland Arboretum in Brainerd. Arboretum plants are not normally included in the range maps. In this case, however, the sighting is on a The Nature Conservancy sight, Paul Bunyan Savanna, which is a part of the Northland Arboretum but is also a natural site.

The sighting in Washington County is at Carpenter St. Croix Valley Nature Center. It was probably planted by the original owners of the property along with many other trees not native to the area.

 
  3/11/2021    
       
         
 

Nativity

 
 

Native

 
         
 

Occurrence

 
 

Rare, localized, and imperiled

 
         
 
Taxonomy
 
  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Pinopsida (conifers)  
  Subclass Pinidae  
 

Order

Pinales (pines)  
 

Family

Pinaceae (pines)  
  Subfamily Abietoideae  
 

Genus

Tsuga (hemlocks)  
       
 

Subordinate Taxa

 
 

 

 
       
 

Synonyms

 
 

Pinus canadensis

 
       
 

Common Names

 
 

Canada hemlock

eastern hemlock

eastern hemlock-spruce

hemlock

hemlock spruce

 
       

 

 

 

 

 

 

 

 

Glossary

Linear

Long, straight, and narrow, with more or less parallel sides, like a blade of grass.

 

Petiole

The stalk of a leaf blade or compound leaf that attaches the leaf blade to the stem.

 

Stomate

A minute, epidermal pore, surrounded by two white guard cells, that allows the exchange of gasses and water vapor. The guard cells control the size of the opening. Plural: stomata.

 

Wing

A thin, flat, membranous, usually transparent appendage on the margin of a structure.

       
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Randy
       

Eastern hemlock foliage, Freeborn County, MN, July 2017

  eastern hemlock    
       
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Slideshows
   
  Tsuga canadensis
Blake C. Willson
 
  Tsuga canadensis  
 
About

Eastern Hemlock

 
     

 

slideshow

       
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Other Videos
 
  Trees with Don Leopold- eastern hemlock
ESFTV
 
   
 
About

Uploaded on Oct 10, 2011

No description available.

   
       
  eastern hemlock (tsuga canadensis) identification video
wvoutdoorman
 
   
 
About

Published on Apr 18, 2012

eastern hemlock (tsuga canadensis) helping id the plant

   
       
  MyNature Apps; Identifying an Eastern Hemlock, Tsuga canadensis
MyNatureApps
 
   
 
About

Uploaded on Mar 30, 2011

How to Identify an Eastern Hemlock Tree. www.mynaturesite.com

   
       
  Eastern Hemlock [Plant ID Guide]
BlackOwlOutdoors
 
   
 
About

Published on Mar 9, 2013

Krik of Black Owl Outdoors identifies and explains some of the characteristics of Tsuga canadensis, or the Eastern Hemlock.

   
       
  Eastern Hemlock Identification
Matthew Loxley
 
   
 
About

Published on Oct 21, 2012

No description available.

   
       

 

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Randy
July, 2017

Location: Freeborn County, MN

Eastern hemlock foliage

eastern hemlock


     
     
 
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Created: 7/1/2014

Last Updated:

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