Hi Gomero,

I seem to remember reading a citation of -15°C for yellow pine cultivars to get properly yellow. Unfortunately, I can't remember where I read it, nor if it was applied to a particular cultivar, or to yellow pine cultivars generally. If I manage to relocate the info, I'll post it.

Resin

I'm sure it's all temperature related Gomero. i.e., some winters better than others.

As to the 1/2 sun from the Oaks in summer for the larger-growing "Trees", I hope you have them planted far enough away that they can develop into full-sized specimens. My only thought.

Dax

the pix i posted under the session posts .. on winter color.. [which i will update when the wind chill is above single digits F] .... were taken in the third week in NOV .... converting C to F ... indicates resin is suggesting 5 F ... IT WAS NO WHERE NEAR 5 degrees here at that time of year .... and many of the plants were already coloring up nicely ....

of course ... different plants.. change at different times ....

BUTanyone else buy the theory????

also .. you left out one fact ... are you buying these locally???? if they are properly colored in the sun, at a local or zone equivalent nursery ... i don't see how the temps would be any different from yours ... if you are shipping them in from colder zones, well then maybe .... give more facts about your sources ....

exactly how many hours of direct sun are you conifers getting... and which hours of the day .... three hours at dawn is not the same as three hours at noon .... more facts please ...

and i really doubt that they would refrigerate them to sucker you into buying them ...

but what the heck do i know.. when it comes to plant physiology .... observation.. yes .. science... nope ....

ken

Hi Michael, -15°C could explain it since over here we get down to that only every 10 years or so. But since those I buy from local/regional suppliers are pretty yellow in the winter, could they artificially trigger the colors by storing the pots overnight in a freezer at that temperature?
And what about other experiences in zone 8, do you get the winter yellows?

Dax, thanks, the oaks are huge (> 20-25 m), no problem for the plants planted around.

Gomero

exactly how many hours of direct sun are you conifers getting... and which hours of the day .... three hours at dawn is not the same as three hours at noon .... more facts please ..

Roughly full sun from noon to sunset.
Summer sun is needed for summer coloring, but, for winter coloring?..hmmm..why not? I am very open minded.

In Maples with attractive winter bark you definitely need good sun exposure to trigger the full color changes and low temperatures are not enough. Maybe the mechanism in conifers is similar.

Gomero

I think your low of 46 F. is your problem. I would suspect they never hardened off. My yellow pines "Zundert' and 'Winter Gold' in October had completed half of the transformation to all yellow. The 46 F had already been achieved by that time. Only when the temperature turned off much colder, 20-30 F did they turn yellow.
just my opinion.
I would also convert them to full sun.

Dave

Hi Gomero,

"But since those I buy from local/regional suppliers are pretty yellow in the winter, could they artificially trigger the colors by storing the pots overnight in a freezer at that temperature?"

I wouldn't be surprised, if it improves the saleability!

Hi Ken, Dave,
Methinks one or both of you are coming badly unstuck trying to convert to that ridiculous fahrenheit nonsense . . . try sticking to standard international measurements :-)

Resin

It's only ridiculous if you don't use it, that's what methinks. I didn't pick up on the - symbol. Sorry about the miscalulation. I think I'll stick to the F since I hardly ever get out of Kansas and stay away from anything related to celsius.

Dave

Early last year I got a couple of Abies nordmaniana 'Golden Spreader' conifers (each in a different mail order shipment).
Although they're both pretty tiny, one of them turned an absolutely unbelievable glowing yellow, while the other remained a fairly ordinary green-yellow.
I have no idea whether the bright yellow one will keep doing that when it gets bigger, but I sure hope so (and that the other one decides to follow suite at some point...)

Just a thought. Did you consider that when you purchase these plants you bought them in containers in the winter?

And in the subsequent winter they are in the ground on your property.

Of course that is a completely different thing. Containerized plants are much more sensitive to cold.

Hi Gomero,
I doubt your zone 8 is the problem, here on the south coast of the UK our winters are probably even milder than yours certainly in recent years, the cultivars you mention are possibly not the very best on offer for winter colour, pinus mugo Carsten (wintergold) is superior to Zundert, sylvestris Gold Coin and Gold Medal probably better than Aurea,although I don,t have a clue what strobus HWG is, perhaps the amount of shade in summer has got something to do with it?
Bluespruce.

How wet or dry are they staying? If they're in a wet environment, that might account for the yellowing, apart from anything else that's going on. They need fast drainage. Is the soil clay, or fast draining sandy gritty stuff?

what is your soil .... have you ever had it tested ... and do you fertilize them .. if so, with what ....

when i was a rose grower ... 8 hours was the bare min. for what is considered full sun ... it may be a problem... but it may not ....

ken

I really appreciate all these comments.
Michael, it would be nice if you find the reference to your -15°C threshold because, according to others, there is good coloring at temperatures much lower than that. Bluespruce, when was the last time you had -15°C? ;-), maybe you are now in zone 9 and you don't know.

The bottom line is that, apparently, we do not know how and why these conifers change color in the wintertime, or, am I wrong?

The garden is in a sloped terrain so humidity is not a problem (in addition in this area rainfall is only about 650 mm ( about 26 inches ;o))). The soil is clay but well amended by a yearly addition of 20 cm (8") of mulch. The conifers (not fertilized) are not the main component of the garden, maples are (of which there are > 250 taxons).

Are there any forum readers who have successfully grown these winter yellow cultivars in zone 8 (or higher) with only 6 (or less) hours of direct sun in the Summer?

Gomero

P.D.: HWG stand for Hillside Winter Gold

Hi bluespruce53 HWG I didn't get a few days ago when I abandoned this thread. It's 'Hillside Winter Gold' (Pinus strobus).

I'll comment once again pertaining the temperature and with regards to what bluespruce53 is saying. I used to live in Portland, OR Zone 8b and very mild and that's where Stanley and Sons nursery is (Boring, OR) where I've seen in their catalog many of the goldens colored up very well. Especially Pinus virginiana 'Wate's Golden' which comes to mind first. Also in their part of USA which is called 'The Willamette Valley', it's said, 'That they have just enough chill to produce Apples with good flavor' so I'm in consensus with most opinion/fact stated.

Dave, you had me crackin' up!

Dax

I lost some of my text. Anyway...

Gomero, it's the cold not the spring summer or fall temps in combination with how much sun it receives in winter. That's the only way I see it. It can't be anything but in my opinion.

Good thread. Lots of thoughts raised... but then again I could see a soil deficiency to repeat myself, being another problamatic source.

Dax

Hi Gomero and Dax,
Thanks for the name Hillside Winter Gold, I can't ever remember the last time it was as cold as -15C, all conifers for winter colour do pretty good though, the problem here is geting various cultivars of dragon eye pines to show their splendour in the summer through lack of heat.
Bluespruce.

but then again I could see a soil deficiency to repeat myself,

Do you have a theory, or, is it just a hunch?

Gomero

Here's another option . . .

:-)

Here is a link that might be useful: {{gwi:634028}}

Nice one resin that will brighten the trees up

NO sorry Gomero - if your foliage is healthy then it's the cold.

Dax

what kind of mulch do you use to amend your planting holes???

we usually recommend no amendments at planting .... ken

Michael: LOL, good idea for the maples, for the Mugo's is kind of time consuming with all those needles...

Ken: The mulch (composted leaves+ shredded branches)is added to the surface each year.

Dax it cannot be the cold only (this last week has been below freezing all the time and lows down to -8°C or 19°F and the tips of the needles of the 'Zundert' begin to turn yellow) the sun must play a role but I do not know how.

Gomero