Increasing the blue of a a Blue Spruce

Is this possible? A friend has a Colorado Blue Spruce with nice blue new growth, but the rest is just green. She wants it to be all blue, even the 'inside' older growth.

She asked me if Aluminum sulphate, used as a soil acidifier for blue hydrangeas and blueberries, would make a difference. Does anyone have experience with this?

Nope, only a can of Rustoleum spray paint will make old foliage new-like blue again.

scott

Aluminium sulphate would make it brown, not blue.

If you're going to use blue paint, make sure it is non-toxic!

Resin

I think Colorado Blue Spruce can be a bit of a crap-shoot as to if it is going to be blue always. In order to be assured of getting a blue Colorado Blue Spruce I think you'd have to get the cultivars like 'Fat Albert' or 'Hoopsii'.

Aha, but coming from the state of namesake and thus being almighty expert on the subject, I think there is a way. Mistreat the bugger. (this is entirely theoretical, I have not measured or anything)
Yes, grafted cultivars are the way to select the bluest individuals.
The blue is a function of waxy cuticle lay thickness/consitency, yes? The layer is to protect the needles from dessication, yes? Plants individuals will adapt themselves to a degree to their environment, like the variation in leaf lobes for amount of light, etc, yes?
The bluest spruces I have seen are those within lawns that are permanently drier (more brown) and more colorful than those on green-green turf areas so watered that they put golf courses to shame.

But this may be superfluous obsevation.

As a note, the wild populations are a fun thing to watch- dappled and mixed. Varying shades of blue to grey to rich, dark green and even near-chatreuse individuals, side-by-side.

K. James

So which is it? Can the external conditions affect the "blueness" or not? I'm seeing contradictory info, here.

Yes, undercover owl, several things can affect apparent color. I agree with JamesCO, except that I don't know that I've ever observed a greener Colorado spruce develop "blueness"; I think that's a function of inherited genetics, not environmental response. I remain to be persuaded.

What needs to be observed is "blueness" of the current season's needles/growth extensions, relative to the remaining previous seasons' needles. One will see that the "blueness" declines with time, and in some individuals the "blueness" becomes green after one season.

Waxy cuticle doesn't last forever. Ill-chosen chemical applications can dissolve this ornamental feature while performing pesticidal tasks (eliminates a problem, but at the expense of why the tree was planted in the first place). Mostly, it's just the natural persistence (or lack thereof) of the waxiness on a particular individual plant/clone. A review of a series of photos of Picea pungens f. glauca clones grown in a collection will illustrate this best. Dax? Resin? PlantFiles?

JamesCO's observation of bluer trees in stressful situations may hold some kernel (colonel?) of truth: slow-growing trees have shorter lengths of new growth, achieving a denser branching effect and appearing "bluer" than trees with longer growth extensions and not-so-dense layering. With fewer needles produced per season, they drop less needles annually and create less bare spaces along old branches. Vigorously growing trees do the converse, but are probably healthier.

I think one will find the "bluest" trees are the ones with the most compact growth, the greatest number of side branches, that start out with the "bluest" needles, and with the most persistent waxy cuticle. The newest growth "hides" or masks more of the older growth (that is declining in "blueness") leaving the viewer with the "bluest" landscape effect.

Ask for that at your next shopping foray.

Ah, VenerableVortex: Perhaps the traditional chemical-bath applications to obscenely green lawns has its effect. Also, like you more experienced-ly pointed out- the internodal length from growth and all- Perhaps the ample (too much) water and excess nitrogen availble to lawn specimens encourage profuse yearly growth at the expense of blueness. My observations are not a hard rule, but a trend I have wondered about.

Somedays I would kill to see the green form! I admit to getting sick of the silly pseudo-state-patriotic things.
Kenton

How tricky. Not worth fussing over, in my humble opinion.

Mine are greenish ones that I bought super-cheaply at a big-box store clearance sale, and I've kept them growing in containers, with plain potting soil. No change in color over time. But I like their greenish color. I don't judge them by the color of their needles, LOL.