blue spruce

(Picea pungens)

               
Conservation Status

IUCN Red List

LC - Least Concern

blue spruce

NatureServe

N5 - Secure

Minnesota

not listed

Wetland
Indicator
Status

Great Plains

FAC - Facultative

Northcentral & Northeast

FACU - Facultative upland

Nativity

Native to Arizona, Colorado, Idaho, New Mexico, Utah, and Wyoming. Widely cultivated as an ornamental. Naturalized.

Occurrence

Uncommon

Habitat

Moist. Shade tolerant.

Pollination

May or June

     
Height

30 to 60

     

Identification

This is a slow-growing, evergreen, coniferous tree rising on a single trunk from a relatively shallow, horizontal root system. It is long lived, surviving 150 to 200 years. In Minnesota mature trees are usually 30 to 60 tall and up to 36 in diameter at breast height. Older individuals in its native range may be up to 600 years old and over 120 tall.

Young and mature trees have a pyramidal crown that is persistent to the base. The trunk is straight and distinct to the top of the tree.

The bark on young trees is grayish-brown and flaky. On mature trees the bark on the lower part of the tree is thick, reddish-brown, and furrowed with scaly, round ridges.

The branches are horizontal and whorled, each whorl representing one year of growth. The tree’s age can be determined by counting the number of whorls from the bottom up. Upper and middle branches are ascending or horizontal. Lower branches are slightly to strongly drooping. The lowest branches often touch the ground.

The twigs are stout, yellowish-brown, and usually hairless. They do not hang downward (droop).

The buds are ¼ to ½ long and rounded to bluntly pointed at the tip. They are covered with overlapping, papery, yellowish-brown scales. The scales are usually bent backward.

The needle-like leaves are widely spreading, somewhat swept toward the tip of the twig, and somewhat curved forward. They may be green, bluish-green, or silvery-blue. They are evergreen and can remain on the tree for up to 10 years. When crushed they emit a pungent resinous odor. When young they are covered with a whitish, waxy coating (glaucous). Each needle is to 13 16 long and 1 16 wide. It is borne singly on a peg-like base that persists after the needle is shed. It is stiff, sharply pointed, 4-angled, and square in cross section. There are two whitish lines of minute openings (stomata) on each surface. Each whitish dot (stomate) is a pore surrounded by two glaucous guard cells. The guard cells control the size of the opening, allowing the exchange of gasses and water vapor.

Male and female cones are borne on the same tree. Pollen (male) cones are rose red when they first emerge. Mature cones are fleshy, yellow to purple, oblong, and to ¾ long. They are borne in whorls of 3 to 5 at the base of new shoots or singly near but not at the tip of the shoot. They appear throughout the crown but are more numerous in the upper half of the crown.

Female cones are covered with pale green scales when they first appear. They are borne usually in clusters of 2 or 3 at the tips of the new shoots. As the cone becomes receptive the scales become red and the cone becomes erect. The scales toward the base of the cone are bent backward 90° or more. At the time of pollination the cones are to ¾ long. They are appear in the upper 10% to 25% crown. Four weeks after pollination the cones hang downward and reach their full size. Mature cones are 2 to 4 long. The scales are diamond-shaped, straw-colored, and papery.

Pollination takes place May or June. Male cones shed pollen then wither and fall away. Female cones mature in August of the first year and disperse seeds in September.

 
Similar
Species

 


Distribution Distribution Map  

Sources: 2, 4, 7.

 
Record

No records are kept for non-native species.


Comments

This is the state tree of Colorado and Utah.


Taxonomy

Family:

Pinaceae (pine)

 

Subfamily:

Piceoideae

 
Synonyms

Picea parryana

Picea pungens f. argentea

Picea pungens var. glauca

 
Common
Names

blue spruce

Colorado blue spruce

Colorado spruce

silver spruce


 

 

 

 

 

 

 

 

Glossary

glaucous

Pale green or bluish gray due to a whitish, powdery or waxy film, as on a plum or a grape.

 

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.

       

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Randy


Colorado blue spruce, Freeborn County, MN, December 2016

  blue spruce   blue spruce
       
  blue spruce    

       
       
       

MinnesotaSeasons.com Photos

   

Tree

  blue spruce   blue spruce
       

Twig

  blue spruce   blue spruce
       
  blue spruce    
       

Female Cone

  blue spruce    
       
       

 

Camera

     

Slideshows

   
  Picea pungens
Blake C. Willson
 
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Colorado Spruce

 
     
  Blue Spruce
DianesDigitals
 
  Blue Spruce  
 
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Copyright DianesDigitals

 
     
  Identify A Colorado Blue Spruce
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Published on Sep 8, 2013

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Other Videos

 
  How to ID Picea pungens
Laura Deeter
 
   
 
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Uploaded on Nov 22, 2008

short video showing the key identifying characteristics for Picea pungens

 
     
  Picea Pungens - Blue Spruce
monolakesaltybathco
 
   
 
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ploaded on Sep 2, 2006

he Mono Lake Salty Bath Company Presents a wild love of picea pungens, the blue spruce. Evergreen needles, 3/4 to 1 1/4", stiff and very ... all » sharp like bayonets, displayed nearly straight out from twig, silvery blue to dark green. Strong acidic taste but makes a fine tea.

 
     
  Trees with Don Leopold - Colorado (blue) spruce
ESFTV
 
   
 
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Uploaded on Nov 16, 2011

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