Weird growth on landscape spruce

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Location
Cleveland Ohio USDA Zone 6a
USDA Zone
6a
#1
I drive by this tree in my neighborhood every day, and only recently noticed the strange growth on the top of it. Would this be considered a witches broom? I know the pic isn't great, but the growth is so rounded and compact and full of cones compared to the rest of the more typical spruce growth habit. 20171009_170114.jpg
 

GGB

Chumono
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Location
Bethlehem, PA
USDA Zone
6b
#4
I drive past an eastern white pine sometime and the top of it is similar to your spruce. It's like a perfect sphere of foliage
 
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113
Location
Central Oregon
USDA Zone
4
#7
Yes, this is a good example of a witch's broom.
It can be caused by an infection (sometimes a virus) or by a genetic mutation.
Mistletoe can also lead to a similar phenomenon.
Many of the "dwarf" varieties of conifers found in nurseries started out as a broom and were collected and grafted onto a healthy under-stock.
Of course the genetic mutations are the desirable ones. The infectious ones don't propagate well.
If you start looking, brooms are not that uncommon in western conifers.
See the American Conifer Society's website for more examples.
 
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592
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Location
Wyomissing, PA
USDA Zone
6b
#8
Yes, it looks like a giant apical witch's broom!

Most of the interesting conifer cultivars/variants come from chance witch's broom discoveries in the wild.
 
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Central Maryland
#9
This happens in reverse too, particularly on the ubiquitous dwarf Alberta spruce, where the mutation that presumably made the original witches broom reverts to normal growth on a tree making what seems a relatively huge, but is actually a normal sized branch. I have a Japanese maple 'Butterfly' in my yard this has happened with, although I'm not sure if that cultivar originated as a somatic mutation like this. I've allowed the reversion to grow since the form is similar to the original it's just the leaves that have lost their variegation, and have a half-n-half tree.