How to Tell the Age of Nursery Stock Junipers

[cedarcanvas]

Hey gang,

I was at a nursery today and was curious about aging trees, specifically junipers.

I wound up picking up a couple of different junipers and posted them HERE on my beginner thread and have no idea how old they are. I thought I’d create a separate thread as I couldn’t really find much discussion through a search and I thought it to be an interesting topic.

I imagine size of pot may be an indicator...as would be info from nursery staff. Are there any rules of thumb based on trunk size, foliage, overall size, etc.?

Thanks!

 

[Quince]

The only way to know for sure is to kill the plant and count the rings. As someone who has spent years working in garden centers though I can tell you that growers want to move the plant as quickly as possible. Most nursery stock is probably not older than one year per gallon pot size.

 

[0soyoung]

One doesn't actually need to kill the plant. Wood samples can be gathered with an instrument like a bone biopsy needle and examined with a microscope.

 

[Wires_Guy_wires]

There's probably a mathematical formula for it.
If the pot size was never restricted, divide the trunk diameter in mm's by 2.5, and add 4 years for the seedling stage. That's roughly how much my wire bites in ever year on adults.
This goes for nursery plants only.
In bonsai pots or yamadori they thicken way slower. I think someone on this forum has a hemlock or spruce with more than 5 rings per mm.

 

[Potawatomi13]

Ask nursery first. If no real help ask for info to contact grower and ask them.

 

[Shibui]

There's no real way to tell. There are so many variables that size alone is no indication of age. trees that are well grown will be much thicker than those that have had inadequate water, feed or poor soil. I've seen many outrageous claims of age from vendors trying to sell inferior trees to gullible customers so never trust the vendor on age.
Even rings are not a reliable indicator of age. New rings are laid down with every pause in growing. usually that's winter so 1 each year but summer drought or food shortage can also add extra rings. Dendrochronology only works by comparing rings with others of known ages to identify recognisable sequences. Otherwise it is just guestimation.

 

[rockm]

If you're buying junipers at a nursery, age is not relevant at all. They're probably under 20 years old, unless they're in 50 gal. pots. The question is do they "look old" That is the key to choosing them, not actual age...

 

[sorce]

"look old"

And, when compared to a Juniper that IS old...
They never will!
Lol!

Can't count rings reliably either, since there can be 2 or zero in a year.

I would personally like to know how long it takes before they get sold in 1gallon containers.

Sorce

 

[Lazylightningny]

There's no way to tell without taking a core sample. Too many variables to guess at it's age.

 

[cedarcanvas]

The only way to know for sure is to kill the plant

Trying to avoid that...perhaps inevitable...

There's probably a mathematical formula for it.
If the pot size was never restricted, divide the trunk diameter in mm's by 2.5, and add 4 years for the seedling stage. That's roughly how much my wire bites in ever year on adults.
This goes for nursery plants only.
In bonsai pots or yamadori they thicken way slower. I think someone on this forum has a hemlock or spruce with more than 5 rings per mm.

@Wires_Guy_wires ?

There's no real way to tell. There are so many variables that size alone is no indication of age. [...]

Interesting about the dendrochronology and coring techniques, seems a little invasive...

...age is not relevant at all.

I can see how aesthetics trump age, @rockm, but some interesting knowledge here...trying to learn as much about my new trees as possible, and was hoping for a vague benchmark, that’s all.

Seems like no hard and fast rules, as I suspected, but some interesting insights...sounds like mine are likely in the neighbourhood of 2-3 years.

 

[Wires_Guy_wires]

There seem to be quite some studies about it from the US and Asia.
Most of them rely on seasonal weather input. But I'll check at work tomorrow if anyone dared to provide any models.

So for now I think my own formula for non-bonsai potted junipers:
(Diameter in mm/2.5)+4 = age
Doesn't sound all that bad.

But yeah, we're forgetting that a tree can be 500 years old.. When we take a cutting of that tree, is the cutting brand spanking new, or is it 500 years?
'the carbon used for this tree was collected recently'
'but the DNA of the tree and the cells produced by it originate from 500 years ago.'
'Only live parts can age, so the tree is probably 40 years old, attached to its own shed skin from decades before that.'
'A rock that came off a mountain is older than the mountain itself, otherwise it wouldn't be up there.'

If you know the answer, let me know. I'm satisfied with not knowing.

 

[rockm]

Trying to avoid that...perhaps inevitable...




@Wires_Guy_wires ?
View attachment 299552



Interesting about the dendrochronology and coring techniques, seems a little invasive...



I can see how aesthetics trump age, @rockm, but some interesting knowledge here...trying to learn as much about my new trees as possible, and was hoping for a vague benchmark, that’s all.

Seems like no hard and fast rules, as I suspected, but some interesting insights...sounds like mine are likely in the neighbourhood of 2-3 years.

There is NO 'Vague benchmark" Age may, or may not, show itself. I've dug 50 year old trees from the wild that look 15 and 15 year old trees that look 100. Environment has everything to do with it. With nursery stock harsh environments aren't really a factor. It is what it is.

Actual Age HAS NO BEARING on trees that don't actually have real "age." Truly old trees show their age for the most part, and by old, I mean over 150 years or so. That's when signs like thick plated bark, sinew in the trunk and surface roots show themselves. Nursery trees typically don't have any of that.

 

[cedarcanvas]

some good points, thanks @rockm.

 

[River's Edge]

Hey gang,

I was at a nursery today and was curious about aging trees, specifically junipers.

I wound up picking up a couple of different junipers and posted them HERE on my beginner thread and have no idea how old they are. I thought I’d create a separate thread as I couldn’t really find much discussion through a search and I thought it to be an interesting topic.

I imagine size of pot may be an indicator...as would be info from nursery staff. Are there any rules of thumb based on trunk size, foliage, overall size, etc.?

Thanks!

I grow Shimpaku from cuttings. Using grow beds and grow boxes they attain trunks of 1 inch diameter in five years. For the first three years some root work is done each year. The Itoigawa are faster growing than the Kishu cultivar. I cannot comment on other varieties but would suspect some differences. Also expect the result if ground grown may vary either way dependant on care routines. My grow beds are on a water system and I use a fairly heavy fertilizer regimen for grow out!
The pot size will mean very little, the grower could easily dig up a seven year old plant, root prune and put it in a 1/2 gallon pot for sale!
The trunk size may not be a reliable indicator depending on the growers abilities and climatic conditions.
Another aspect is if the tree has had any root work done during the process, as this can slow down the growth temporarily!
Foliage is no indicator as every grow prunes differently during development.