Engelmann Spruce and Blue Spruce are very similar and difficult to distinguish from each other, but knowing several characteristics helps: 

Elevation: Engelmann Spruce likes drier and higher slopes (9,000' to tundra krummholz); Blue Spruce likes streamsides and lower elevations (7,000' to 10,000'). 

Cones: Engelmann cones are usually less than two inches long; Blue Spruce are usually about three inches. Engelmann cones are deciduous after seed maturity; Blue Spruce cones are persistent following seed maturity.  

New growth: Engelmann twigs or leaf bases are hairy; Blue Spruce twigs and leaf bases are glabrous (without hairs). 

Trunks: Engelmann tree trunks are usually clean between main branches; Blue Spruce trunks are often cluttered with small sprigs of growth.  

Bark: Engelmann trunk bark on older trees is often cinnamon and scaled; Blue Spruce bark on older trees is gray and furrowed.   

Leaves: Engelmann leaves are relatively flexible, tending to have blunt or acute, but not sharply pointed tips. Blue Spruce leaves are rigid and sharply pointed.

Color of leaves: Both species often have new leaves that are blue-green, the result of a glaucous coating. Rub the leaves and you will wipe off the coating. Picea pungens does tend to have more blue-green growth, but that overall blue-green cast of domesticated Picea pungens is due to commercially grown stock which is selected for the blue-green color.

     Intermountain Flora states that since there are places "where it is nearly impossible to assign specimens to either [Picea Engelmannii or Picea pungens]... it would seem logical to treat these... as varieties of a single species". Other floras treat the species as distinct and distinguishable.

    "Picea" is derived from the Latin "pix", or "picis", meaning "pitch", and is the classical Latin name for a now unknown Pine.

Picea engelmannii, Engelmann Spruce
Picea engelmannii
Picea engelmannii (Engelmann Spruce)
Pinaceae (Pine Family)

Montane, subalpine, alpine. Woodlands. Spring.
Horse Creek Trail, June 6, 2004.

On dry, well drained or highly exposed sites above 9,000 feet, Engelmann Spruce is usually the dominant tree. The fifty foot, young trees pictured at left stand in front of a mountain-side of Engelmann Spruce. Trees can grow to well over 100 feet tall and four feet in diameter or they can be stunted above tree line in krummholzPicea engelmannii is one of a number of trees that has another distorted growth form: Witches Broom

Charles Parry collected Picea engelmannii in Colorado in 1861, and in 1863 George Engelmann, eminent St. Louis physician, botanist, plant collector, and the President of the St. Louis Academy of Science described it in the Transactions of the Academy of Science, St. Louis, volume 2 1861-1868, page 212

I suspect that many of the details in the description that Engelmann wrote and presented to the Academy were supplied to him by his friend and botanical colleague, Parry, but Engelmann gets the credit for the description.

The complete name for this species is,   Picea engelmannii Parry ex Engelmann.

"Ex" is Latin for, "from".  So the literal interpretation of the above name would be, that Parry took the name and/or description from Engelmann. (Zoology reverses the order of the names when "ex" is used.) The actual meaning is just the reverse: Engelmann used some or all of Parry's name and description for this new species. Parry may have written about the new species in some publication, but he did not provide a full, botanically acceptable, description.

In 1879 Engelmann also published the description of another famous tree that Parry discovered, Picea pungens, Blue Spruce.  See below for the story of the naming of this tree.

Click for more biographical information about Engelmann.

Click to see the amazing way Picea cones are pollinated and to see Picea engelmannii in winter.

Click to see Picea engelmannii in its krummholz form.

Click for more Picea Engelmannii and Picea pungens photographs and descriptions.

Picea engelmannii

Picea engelmannii

Picea engelmannii (Engelmann Spruce)
Pinaceae (Pine Family)

Montane, subalpine, alpine. Woodlands. Spring.
Lizard Head Pass Meadow, June 20, 2006 and Lizard Head Trail, June 25, 2013.


Picea pungens, Blue Spruce

Picea pungens

Picea pungens (Blue Spruce, Colorado Blue Spruce, Water Spruce)
Pinaceae (Pine Family)

Montane, subalpine. Woodlands. Spring.
Ryman Creek, May 18, 2006.

Blue Spruce likes moisture and is commonly found at the side of mountain streams and on moist mountain-sides.  

Blue Spruce is the state tree of Colorado (until 2015 also the state tree of Utah) and is found in magnificent stands in the mountainous parts of Colorado, Utah, Idaho, Arizona, and New Mexico.  The range of Blue Spruce is more limited than that of Engelmann Spruce which reaches to the Pacific Coast and into western Canada (see range maps below). 

Because of its beautiful color and lovely symmetry, Colorado Blue Spruce is frequently planted as an ornamental in many parts of North America.  The ornamentals are selected for the blue-green (not really blue) color, often present only in new leaves in wild specimens.

Blue Spruce and Engelmann Spruce are very similar and are often difficult to tell apart.  See the top of the page for a comparison of their characteristics.

George Engelmann, St. Louis doctor and highly respected botanist, named and described Picea pungens in 1879.  The first authenticated collection of this tree is that by Charles Parry in 1861 from Clear Creek, Colorado. Parry sent some of these collections to his friend Engelmann.  (Click to see this specimen in the Missouri Botanical Garden herbarium.)  I think the gap of 18 years between the time Parry collected the species and the time Engelmann described it can be accounted for by misidentification.

When Parry collected the specimen in 1861 he and Engelmann considered it to be an already described species, Abies menziesii. This name had been given by John Lindley in 1835 to the Pacific coast giant Spruce trees, what we now call Sitka Spruce, Picea sitchensis.  Parry, Engelmann, and others of the time believed that the Blue Spruce was the same as the Sitka Spruce and they thus used the name Abies menziesii for Blue Spruce, as the name on the above referenced Missouri Botanical Garden herbarium specimen indicates.

Mistaken nomenclature with regard to Abies menziesii preceded Parry and Engelmann, for when Lindley honored Archibald Menzies (doctor, botanist, explorer) with the Abies menziesii name he did not know that the name had already been used by Charles Mirbel in 1825 to name the tree that we now call Pseudotsuga menziesii, the Douglas Fir Mirbel's use of the Abies menziesii name apparently was not widely publicized in 1825 and was unknown to almost all botanists until 125 years later. (The naming of Douglas Fir is quite a contorted story in itself and is nicely told by James Reveal on the Lewis and Clark web site.)

The  identification of Blue Spruce as Sitka Spruce persisted into the 1870s.  For instance, Thomas Porter and John Coulter labeled the plant Abies menziesii in their 1874 Synopsis of the Flora of Colorado (the first flora of Colorado).  And Townshend Brandegee, botanist to Ferdinand Hayden on the Hayden Expedition across southern Colorado, identified the conifers he found as Abies: he called Engelmann Spruce, Abies Engelmannii; Sub-alpine Fir, Abies grandis; and Blue Spruce, Abies Menziesii.  (Capitalization and spelling is Brandegee's.)

In September of 1874 Engelmann was in Colorado and collected specimens of Blue Spruce.  Click to see the Missouri Botanical Garden herbarium specimen of Blue Spruce that Engelmann collected in 1874.  Notice the tag in the lower left corner that indicates in Engelmann's handwriting that he collected his specimens near Clear Creek, Lindstrom, Colorado (Parry made his collection in 1861 along Clear Creek); that he believed the tree never grew higher than 8,500 feet; and that he called the tree Abies menziesii.

Perhaps his personal examination of the trees gave him a better understanding of their characteristics and he realized they were not the same as Sitka Spruce and they belonged in the genus Picea not Abies. Perhaps Engelmann was also prompted to re-examine the Abies menziesii name for the plants he and Parry had collected in Colorado after he read that in 1855 the Sitka Spruce was renamed Picea sitchensis by Elie Carriere in his book, Traité Général des Conifères.  Engelmann may also have been prompted to rename the Colorado collections because in Carriere's 1867 revision of his book he proposed new divisions of Conifers including reassigning a number of Abies species to the genus Picea.  

For whatever reason, in 1879 Engelmann did describe and name this tree Picea pungens.** 

There are more convolutions in the naming of two Spruces that Parry collected in 1861:  Parry published two names for his Engelmann Spruce: Picea engelmannii (May 4, 1863) and Abies engelmannii (May 4 and October 31, 1863).  Parry and Engelmann must have published the Abies name because they believed their May 4, 1863 publication of the name Picea engelmannii was in error.  Substantiating this supposition is that, as discussed above, Engelmann named the other of the two tree species that Parry had collected, Abies menziesii. See the Transactions of the Academy of Science of St. Louis, pages 122 (where Parry refers to the species as "Abies Engelmannii") and 212 (where Engelmann refers to the species as "Picea engelmannii").

That would explain why the botanical literature of the 1870s calls both plants "Abies"In an email to me about the naming of these two Spruce species, James Reveal indicated, "The concept of what constituted a genus among the conifers was in a state of flux in 1863 and would only be resolved with Carriere's publication four years later. No doubt Engelmann decided that Picea should be included in Abies. (This was the view of many at the time)."

One more piece in this puzzle: Blue Spruce and Engelmann Spruce are, as the  maps below show, very common western species. How is it possible that previous western explorers and botanists (Meriwether Lewis, David Douglas, William Gambel, Edwin James, Augustus Fendler, John Fremont, Ferdinand Hayden) missed these very common trees?  Are there collections and names that have been overlooked?

Part of the answer to this question came in an email exchange between James Reveal, Stanley Welsh, and myself.  Welsh is an expert on Fremont's botanical collections (see his book, John Charles Fremont, Botanical Explorer, available from Amazon) and he indicates that Fremont actually did collect what came to be known as Picea engelmannii, nearly twenty years before Parry collected it: 

"As to the Picea specimen cited as engelmannii in my write-up of Fremont's collections, you [James Reveal] have already noted that the Los Gatos [California] information on the label, is wrong as to the year of collection, and it is also probably wrong as to location [central California].  [Fremont's] label information was open to question more likely than not, and he had probably... [collected it] in 1845, but God knows where." 

Fremont collected for John Torrey but the specimen in question apparently never made it to Torrey, was never described, and thus was never credited to Fremont.

The naming of plants is often not a simple story.


**The genus name, Picea, was first given by Albert Dietrich, Prussian botanist, teacher, and for the last twenty years of his life, Curator of the Royal Botanic Gardens of Prussia.  Dietrich probably named this new genus in his 12 volume, 1833-1844, flora of Prussia: Flora Regni Borussici. Flora des Königreichs Preussen oder Abbildungen und Beschreibung der in Preussen wildwachsenden Pflanzen

Click for more biographical information about Parry

Click for more biographical information about Engelmann.

Picea pungens (Blue Spruce, Colorado Blue Spruce, Water Spruce)
Pinaceae (Pine Family)

Montane, subalpine. Woodlands. Spring.
Cross Mountain Trail, August 19, 2008.

Blue Spruce is most often a beautifully symmetrical tree but not always blue.  These 70 year old youngsters sit above a perennial mountain stream at 10,000 feet. 

Notice that lower (older) branches slant downward, middle branches are nearly horizontal, and upper branches slant upward.

Picea pungens
Picea pungens (Blue Spruce, Colorado Blue Spruce, Water Spruce)
Pinaceae (Pine Family)

Montane, subalpine. Woodlands. Spring.
Near Yellow Jacket Canyon, June 8, 2004.

"Pungens", Latin for "prickly or penetrating", aptly describes both the feel and smell of the leaves of this tree for they are stiff and sharp with a strongly penetrating and pleasant aroma.  New needle growth is soft and commonly blue-green from a glaucous coating.

Picea pungens
Picea pungens (Blue Spruce, Colorado Blue Spruce, Water Spruce)
Pinaceae (Pine Family)

Montane, subalpine. Woodlands. Spring.
West Mancos Trial, October 9, 2008.

Most Picea pungens have small branch growth along the main trunk giving a raggedy appearance. 

Older trees such as this three foot diameter one have brown-to-orange bark. 

Click for more Picea Engelmannii and Picea pungens photographs and descriptions.

Range maps © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Questionable presence

Range map for Picea engelmannii

Range map for Picea pungens