Depending on soil temperatures, the roots of evergreen trees (not just conifers) can grow all year round as these trees never enter a full dormancy like their deciduous counterparts do. If the soil temperature remains above 36F, roots will continue to grow regardless of the time of year, although the colder the soil temp, the slower the elongation. The most extensive root growth happens in late spring into early summer, once soils warm to close to 50F, and again in fall when soil temps are similar. There is a risk with fall planting in colder climates as temperatures decline more rapidly than the roots are able to extend and the root system is unable to support the tree adequately through the winter.

Thanks! Did you mean to say that there is a summer slowdown in root growth? Why is that?

Thanks for digging up the gem! Yeah, I meant Embo. Hope he will rejoin us, I saw a couple of his postings not long ago.

Trying to think a bit broader than just conifers, wouldn't any new planting lead to vigorous root growth as that's the part of the plant that is the most disturbed?

per embo: Existing roots do most elongating (60%) of the whole year when overwintering terminal buds have set and they send a chemical signal to roots.

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if you think of the root system.... as energy storing system ... for future growth.. it would make logical sense.. that after the buds are set.. its time to store energy.. for spring growth... it will most likely be too cold.. to create the energy.. for immediate spring growth... so we have to use the previous stores of energy....

that presumes... a tree has logical sense..

ken

I wonder how the research on root growth is conducted, you can't see roots growing in the soil ...

Timely post as I was doing a quick check on plantings so far. I have two that havent taken hold quite yet ....it hasn't passed the slight yank test

Are you planning any corrective action or do you let mother nature sort it out?

Where there is a will there is a way....

No corrective action...Mpther Nature will determine it's fate. These are new plantings this year....

It's rooted - just not passing the tug test.