Perhaps the other blue spruces' you saw where grafted. These can produce cones at an earlier age than ones raised from seedlings.

Yes menno, that along with conditions could very well be a culprit.

Dax

Thanks pinetree30, menno and conifers for replying to my question. The explanation makes sense since those trees are barely 5 feet tall and our blue spruces are at least 12 feet tall with no cones in sight.

Could you please explain in basic terms why a grafted tree would produce cones faster than a seedling-grown tree? I've read very little about grafting so any info you could pass along would be appreciated.

Thanks.

Grafting and other methods of asexual propagation allows the plant to leave its juvenile stage much faster and enter into the reproductive stage. That's ONE reason why propagation via cuttings, grafts, etc., is so important to professionals and hobbyists alike.

"Grafting and other methods of asexual propagation allows the plant to leave its juvenile stage much faster and enter into the reproductive stage"

. . . because the scion grafted on is taken from an adult plant, and is therefore already adult, right from the start.

Resin

My understanding is that more stress = more propagation. This law is true in the animal kingdom as well. If this is the case than a tree doing well will have less propensity to propagate.

That is the widely held popular received wisdom, and certainly seems to be supported by circumstantial evidence. But Pinetree30 will (I think!) point out there is no hard verified scientific evidence for it.

Resin

Extraordinary cone production is sometimes called the 'death cast". The tree may be in the process of rejecting the graft.
With fruit trees and grapes the practice of manually root pruning is sometimes practiced to induce heavier fruiting the following year.
As mentioned earlier, the stress of transplanting or drought may cause conifers to produce more cones than normal.
Pinetree 30 needs to explain how "sufficient nitrogen fertilizer" applies to this query. Seems to me it would be just the opposite.

Sam

"Just the opposite" indeed. Cone production, and ways to increase it, have been studied for many decades by foresters, horticulturists and forest geneticists. The results they have obtained are wildly inconsistent.For example, it is often claimed that root pruning increases cone production, but controlled experiments are few and far between, and reported results vary all over the place. Nitrogen fertilization is a standard practice in seed orchards, and irrigation is frequent. Yet there are many observations of cone crops increasing in droughts. There are also numerous claims of cone crops being stimulated by root disease. One problem is that you cannot tell whether a given tree that receives a certain treatment would have behaved differently if left alone, since cone crops are a normal thing to happen.
Anyway, all reviews of the topic I have seen have been unable to come to broad conclusions.