It was a balmy 9 degrees this morning. The cold is ridiculous due to how early and persistent it is. My soil is completely froze. With temps averaging 15-20 below average for close to 2/3rds of November, can you tell I'm excited for winter? If we had some snow I'd be happy but its bare out there.

We had an exceptional number of freezes in October but it never dipped below 28. Surprisingly I didn't see any trees affected by it. As you saw we had some nice color.

I think one very important factor is how warm or cool it is prior to the freezes.

For example Ginkgo is very sensitive but never dropped during these temps. Key factor is that it was cool through late September and October so probably started the process early.

Other years they just dropped green but thats when we have plenty warm weather in the 70s during September and early October.

The only species that was relatively undamaged during those nasty spring freezes in 2012 was Aesculus.

Acer palmatum and some larch where the only ones that did not recover.

Catalpas are frost sensitive in the spring. We got a frost in early may a few years back after the crazy warm March/April and it burned them.

Interesting write-up. I would assume that with most deciduous species, the changing fall foliage would be at least somewhat more freeze tolerant because of the presumed accumulation of secondary metabolites. The plant is finished sucking the "good stuff" - water and sugars back into the roots. It cuts off this connection, but until the chlorophyll is fully degraded presumably some sugars continue to be made. Except moisture is decreasing because the plant is no longer pumping it up but pulling it down. So fall leaves seem to shrink and dessicate, I assume what ions are present gets concentrated. Thus providing at least a degree of freezing point depression. I could be wrong though because I don't find anything about this when googling. It seems to make sense, but I wasn't really paying attention in plant physiology class. (one of the worst professors I had in college)

23F? Brrrr. Just went outside, still see flowers on: Thunbergia vine, Phygelius, Delospermas, Nerines although they are almost done for the year, and Origanum 'Kent Beauty'. (yes, both the bract and the real flower intact) The top of the Thunbergia though is showing some additional burning after what happened a week ago. It's the flowers right near the ground that are still OK. So I'd say there was some formation of frost but not prolonged temps below 30F.

This post was edited by davidrt28 on Sat, Nov 15, 14 at 12:22

Is it just me or do freezing temps also push fall colors towards pale and yellow? My nyssa was red until this week when its colors went pale red. Same for a couple viburnum cultivars.

Then, there are the broad-leaved evergreens (holly trees, evergreen magnolias, etc.) that do not change despite the freezing. Deciduous ones? My Japanese 'Bloodgood' maple is still in full leaf as prematurely COLD as it is!

I have seen some oak seedlings retain leaves all thru a Z8 winter and have had Bur Oak seedlings color red. These "fawn spot" colors and winter hardy leaves all seem to disappear by age 3 or so.

Scot, are you referring to non-marcescence species?

Nice red fall color is usually seen on many Oak seedlings.

Took some observations after the early (for me) freeze.

The most freeze resistant deciduous tree in my garden is Cornus florida urbiniana. Leaves are only about 1/2 red, but the freeze did not affect them at all. I know from prior years it will peak around early December and they will finally fall off by January. OTOH, Japanese maple leaves have all shriveled up from the cold and will fall soon. (and btw, flowers of Camellia 'Mason Farm' not at all freeze resistant. All turned to mush, I'd mentioned in another thread they've never really bit hit by freezing because it usually finishes blooming by Thanksgiving.) The next most resistant, Fagus 'Rotundifolia'; which is always late to turn in fall and very late to leaf out in spring.

Finally, driving around I see a couple Taxodiums I know of, whose orange-brown leaves also appear not to be bothered by freezes, and are a little showier than most of the late-hanging oak leaves, most of which are a rather plain and unattractive brown. (like paper bags hanging) In fact comparing my Metasequoia 'Ogon' to Taxodium, it looks like the Taxodium foliage is a little more freeze resistant. Might just be because they are old specimens, though.

My oak seedlings, Q. coccinea and Q. michauxii, the leaves are still alive. I'm a bit shocked as we got to 17 Tuesday night/Wednesday AM.

Most trees quickly turn color or defoliate after repeated freezings, but my Shumard/Nuttall oak seems indifferent & actually about full scarlet now, tho a bit subdued this yr. It seems to like repeated frosts for the color to develop. Then it holds on to almost every browned leaf thru the winter.

It's interesting, beng.

Most mature oaks whose leaves were still "moist" (since many oaks retain color as the leaves become dry), now have visible leaf "damage" from the freeze (I hesitate to call it damage as they're going dormant regardless) as I survey. The Sawtooth oaks which were just getting yellow are now crispy looking in some cases. Most oaks were already in the colored but drying phase, except some Scarlets which look "Okay" but with some either freeze damage or some natural drying starting to set in.

However, my little seedlings, while mostly red (with some green still) look as if nothing happened.

The Metasequoias for the most part that had turned look the same, but the ones that still had some green are now dark/limp/crispy.

The sweetgum leaves are dried looking now and were still firm and pliable (regardless of color) just a few days ago, so I'd guess the freeze did it.

A lot of the still-green understory shrubs are now crispy or wilted as well.

hair, yeah, driving the other day showed the only good color left on slopes were -- scarlet oaks. That way I could identify the number and location of scarlet oaks.

Yup - still some good Scarlet Oak color around. There are a few colored clingers on some red maples, but they're dried and pale now.