There are some lists published, but the variability does make them rather unreliable - as well as from individual to individual, it can also vary with climate, location and altitude, so a list published from observations at one site may not be relevant to another site even just a fairly short distance away.

Some dwarfs don't cone at all, ever; others do so profusely, from an early age. I don't think any generalised conclusion can be drawn.

Resin

Well I ask for two reasons I guess, first, I think they are an interesting feature and I wonder if Ill be old and gray before any garden confiers I have develop cones. Second, I think it would be fun to sow the seeds from some.

Does anyone have a Thorsen's weeping hemlock that has developed cones? any dwarf western hemlock? Any dwarf hemlock of any species? I think the cones of the species are particularly attractive. By the way, I know that the Thorsens is supposed to "dwarf" (grow 1-6" a year), but just judging by the growth Ive seen on the little one I got this year, I think it could exceed 6 inches in a year.

As for generalized conclusions - I'd guess that cultivated conifers that are fixated on a juvenille stage might tend to be in the class that never develop cones. Just a guess - am I right Resin?...Anyone?.....Bueller?

Hi Tcharles,

     "I wonder if Ill be old and gray before any garden conifers I have develop cones"

It shouldn't be that bad (unless you're nearly there already!). Some will likely have cones within 5 years of planting.

     "... Any dwarf hemlock of any species?"

I've seen cones on Tsuga canadensis 'Microphylla'. Like its leaves, they are very small, only about 5-6mm long (compared to 15-20mm for cones of the natural species).

     "I'd guess that cultivated conifers that are fixated on a juvenille stage might tend to be in the class that never develop cones"

By and large, yes, though some can do so occasionally (e.g. I've seen cones on the juvenile-foliage cultivar Cryptomeria japonica 'Elegans').

Resin

they will do it when they are darn well ready to do it.. and not a moment sooner ...

stresses .. like transplant can cause a few cones on a juvey ....

drought the prior year also ...

as per above.. when they want to ... lol

ken

I've heard about water stress. Giving the tree a disease would work too! I have a sick oak tree that is dropping a bumper crop of acorns.

Ive been Doing some research about this and wanted to share. I found an absract from a article published a few years ago in a forestry journal. It was pretty interesting.

The article summarizes a study done on canadian hemlock trees to increase cone production. The idea being cone production can be sporadic even on old trees and seedlings are needed becuase the tree has timber value.

Anyway, their approach was to apply Gibberlin, a synthetic plant hormone I guess. At the right time it had a significant effect increasing cone production - That wouldnt help you get a juvenille tree to cone necessarily, but the idea is a good one (i think). If someone has a dwarf that has coned - you could get more this way - For most people I guess this is the tail wagging the dog so to speak - but if someone wanted to develop a new dwarf variety of a given species - and they had lots of time and space on their hands - could be worth trying.

I would think that different plant hormones could speed the process of "maturing" a cultivated variety of conifer. However, it would be a risky little experiment. I for one would hate to spray a hormone on a old slow growing plant if I didnt have a real good idea how well the plant would tolerate it. Anyway, I'm sure some plant breeder has dabbled in this . Im going to check the PIIPS papers...I'll report back.

My Sergeant's Weeping, planted less than 2 years, is covered with cones right now. No idea of its age at planting.

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One fact that means absolutely nothing:

All witches' brooms are female (have the ability to cone).

If I were to guess though, a seedling grown 'juvenile' would probably cone more readily but I have no data to support that.

Dax

"All witches' brooms are female"

Naaah . . . just those who sit on them, not the brooms themselves

;-)

Resin,
You should be a conifer stand up. Er a tree/conifer comedian. The "what to plant at the new fire station" question/topic was a hoot! Your answers were burning bush & smoke tree! Haaa Haa!

It is good to have cultivated humour!!!
Cheers,
Greenrr

For president! (several 'sides' to this one as well)

There's a good list of coning ages in Agriculture Handbook 450, Seeds of Woody Plants in the United States, though it is out of print and may be hard to find.
The idea of "stress cone crops" is an old chestnut that can never quite be pinned down, because there is no operational definition of stress to apply to it. Reports of heavy cone production in diseased or damaged trees never have controls for comparison, and have other possible explanations.
Giberellins work fairly well on some cypress family trees, not usually on pine family members