Is it recommended that one of the two top tips be cut off and if so,
which one. the lower or the upper.

How big is the tree?

How big is the tree?

The tree is roughly 4 feet tall.

Remove the one that will leave the best overall shape.
Alternately you can remove 1/2 of one and allow the other to grow
larger for a season and then remove the rest of the one you cut half
from.

wrote:

Is it recommended that one of the two top tips be cut off and if so,
which one. the lower or the upper.

Yes and always cut off the lower one, never the highest one. Most
spruce, and especially Colorado Blue Spruce, have a type of apical
dominance that does not transfer to lower branches like it does in most
other plants. This means that if you cut the leader off a spruce, you
will probably end up with a bush and not a tree.

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Your point is overstated. If the leader of a blue spruce is broken or cut
off, one nearby young branch will take over as the leader, and the tree will
continue to grow like a tree, not a bush. Last year I had 3 twigs vying to
be the leader and growing vertically. Now the dominant one has been
determined, I wonder how, and the other 2 are turning horizontal.

Sometimes 2 leader candidates both continue to grow vertically and you get 2
trunks. Apical dominance seems to be effective only near the very top, and
once they grow long enough with side branches, neither will turn horizontal.


"Stephen Henning" wrote in message
news
wrote:

Is it recommended that one of the two top tips be cut off and if so,
which one. the lower or the upper.

Yes and always cut off the lower one, never the highest one. Most
spruce, and especially Colorado Blue Spruce, have a type of apical
dominance that does not transfer to lower branches like it does in most
other plants. This means that if you cut the leader off a spruce, you
will probably end up with a bush and not a tree.

--
Pardon my spam deterrent; send email to
Cheers, Steve Henning in Reading, PA USA
http://home.earthlink.net/~rhodyman

"Andrew Ostrander" wrote:

Your point is overstated. If the leader of a blue spruce is broken or cut
off, one nearby young branch will take over as the leader, and the tree will
continue to grow like a tree, not a bush. Last year I had 3 twigs vying to
be the leader and growing vertically. Now the dominant one has been
determined, I wonder how

The highest bud becomes dominant and releases auxins that prevent the
lower ones from becoming dominant or growing vertically. It is an
especially strong response in Colorado Blue Spruce. An older spruce
can take several years to recover and develop a new leader. There are
documented cases where removing the leader without creating a dominant
bud has resulted in such stiff competition among buds on the highest
whirl that a new leader never formed and the Blue Spruce were
essentially turned into bushes.

Sometimes 2 leader candidates both continue to grow vertically and you get 2
trunks. Apical dominance seems to be effective only near the very top, and
once they grow long enough with side branches, neither will turn horizontal.

Apical dominance is caused by the upper most bud releasing auxins that
keep lower buds from becoming dominant or growing vertically. When
pruning Blue Spruce Christmas trees, care is taken to cut at a 45 degree
angle just above a bud so only one bud gains dominance and only one
leader forms. Any time that dominance is transfered, vertical growth is
stunted. Since Blue Spruce are slow growing trees, this stunting can be
a problem.

In Christmas tree production, pruning is done both to control size and
shape but to also insure a dominant bud.

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Pardon my spam deterrent; send email to
Cheers, Steve Henning in Reading, PA USA
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Yes, this is certainly my understanding too. But you wrote that "the
highest bud becomes dominant". How does it know that it's the highest bud?

"Stephen Henning" wrote in message
news
"Andrew Ostrander" wrote:

Your point is overstated. If the leader of a blue spruce is broken or
cut
off, one nearby young branch will take over as the leader, and the tree
will
continue to grow like a tree, not a bush. Last year I had 3 twigs vying
to
be the leader and growing vertically. Now the dominant one has been
determined, I wonder how

The highest bud becomes dominant and releases auxins that prevent the
lower ones from becoming dominant or growing vertically. It is an
especially strong response in Colorado Blue Spruce. An older spruce
can take several years to recover and develop a new leader. There are
documented cases where removing the leader without creating a dominant
bud has resulted in such stiff competition among buds on the highest
whirl that a new leader never formed and the Blue Spruce were
essentially turned into bushes.

Sometimes 2 leader candidates both continue to grow vertically and you
get 2
trunks. Apical dominance seems to be effective only near the very top,
and
once they grow long enough with side branches, neither will turn
horizontal.

Apical dominance is caused by the upper most bud releasing auxins that
keep lower buds from becoming dominant or growing vertically. When
pruning Blue Spruce Christmas trees, care is taken to cut at a 45 degree
angle just above a bud so only one bud gains dominance and only one
leader forms. Any time that dominance is transfered, vertical growth is
stunted. Since Blue Spruce are slow growing trees, this stunting can be
a problem.

In Christmas tree production, pruning is done both to control size and
shape but to also insure a dominant bud.

--
Pardon my spam deterrent; send email to
Cheers, Steve Henning in Reading, PA USA
http://home.earthlink.net/~rhodyman

"Andrew Ostrander" wrote:

Yes, this is certainly my understanding too. But you wrote that "the
highest bud becomes dominant". How does it know that it's the highest bud?

Because it doesn't have it's dominance stopped by any other terminal
buds.

All terminal buds try to release auxins that travel down and only down
to other buds below them and keep them from being dominant. Since there
is no bud above the top bud, it keeps its dominance. Buds that are
nearly side by side have trouble preventing dominance in each other.
The higher the dominant bud is above any other buds, the better shot it
has at establishing dominance over the other buds.

--
Pardon my spam deterrent; send email to
Cheers, Steve Henning in Reading, PA USA
http://home.earthlink.net/~rhodyman