Using 1 to 5, ranking only those I have some familiarity with :

Japanese Maple
Red Mape
Sugar Maple
Eastern hemlock
Magnolia grandiflora -3
Magnola stellata
Metasequoia -2
Taxodium distichum -3
Pin Oak
Cedrus atantica -1
Ginkgo biloba

Thanks, Scotjute.

Ranking is just my opinion. Only the first two are considered drought tolerant. The others are either moderate to low drought tolerance.

Ginkgo biloba
Pin Oak
Taxodium distichum
Red Maple
Sugar Maple
Eastern hemlock
Magnola stellata
Japanese Maple
Metasequoia

Haven't grown or seen these growing around in my area to comment.

Cedrus atantica
Magnolia grandiflora

My list would be similar to Whaas's.

IMO 20 foot trees are the most difficult. Too big for casual sprinklering to help much and without the reserves of a large tree.

Also I believe bald cypress, red maple and metasequoia can get used to the damp locations they are planted in. Years like this many of the non fish holding ponds have dried up and there go the nearby cypress.

Maples on the whole have impressed me this year.

Interesting that SILVER maples look to be more stressed than SUGAR maples. I'm completely confused by the trees "showing" stress.

You know, showing stress. With me that means droopy leaves, mis-colored foliage, smaller than average foliage, dieback.

Evergreen conifers on the whole just show up dead one day unless they are "skylands" which will burn and warn ya. Now a good broad leaf tree shows its feelings like a drama queen.

This question can be complicated by soil type. Some trees may be drought tolerant on some soil types and not on others. Of course, most trees on deep soils will tolerate drought well.

As for sugar maple, there is at least one very drought toloerant variety--the Caddo sugar maple.

Also, red maple, while often a bottomland species, is also very drought tolerant and grows well on dry ridges.

Well, I am sorry I can't give a clear ranking of all the trees in your list, but the Caddo sugar maple and red maple should do just fine in droughts.

However, they must be given time to get established. I find that red maple can take longer than some trees to get established so its drought tolerance is fully developed. They will need watering for several years when it gets dry. The Caddo sugar maple may develop its drought tolerance faster.

--spruce

I would put eastern hemlock further down the list.

I'd put Cedrus atlantica at the top of the list and the trees from SE Asia at the bottom. North American natives in the middle.
Mike

Yes, as for Cedrus, I might go with botann. I have heard that Cedrus deodara is very, maybe even extremely drought tolerant, and may be at or near the top of any list of drought tolerant trees. This drought tolerance may hold true for all the Cedrus species.

After looking at this topic, I spent a bit of time on-line looking for lists of drought tolerant trees, and in addition, searching drought tolerance for a number of specific trees. What I find is that there is a fair amount of disagreement about some species.

Why so much disagreement? Partly the difference in soils I mentioned in my earlier post. Next, I think some people are confused by the establishment period needed. Some trees may not develop good drought tolerance for 5 or maybe 10 or more years after planting. I found Taxodium distichum on several lists of drought tolerant trees, but in a couple of places, the comment was made that it took time for that tolerance to fully develop.

But here is the most important thing I can say about this topic--all the trees on the list will have at least good drought tolerance on good deep soils. I would advise anyone to plant any of these trees and not worry. Of course, in exceptionally hot and dry areas of the country, some of these may perform significantly better than others. If you live in an especially drought prone area where it is also very hot, you should contact your local university ag extension or forestry office for advice. And, in the case of a historic drought, like that many parts of the country are experiencing now, almost any tree will be vunerable, depending on the specific soil and other site factors.

--spruce

Thanks spruce man and others for your research. I figured the Cedrus was high because it is North African in origin (Morocca). I also noticed some differences regarding both Taxodium AND Metasequoia. Good points about soil types and estabablishment periods. Newest is the Cedrus--as I was thinking of drought potential. I think everyone needs to plant with that likely potential--even in WET areas as they do seem more frequent. Local weather went from HOT and ARID to HOT and VERY HUMID so thunderstorms have eased dry conditions greatly recently. Hope we all see more rain soon!

Njoasis:

Yes, we DO need to understand which trees are drought tolerant. In 2002 wife and I had our house built on 16 acres about 15 miles north of Winchester, and I started planting trees. There was not a one here then. I have about 120 varieties, and something like 700 individual trees planted. This is a drought area. July rainfall averages about 2.8 inches, and it seems like every other year--or more often--we have 30 day rainless periods. Last year we went 38 days!

But right here we have good deep soils, with the rooting zone going down 50 to in some places about 70 inches, so just about any tree, after it is well established, can survive droughts. Two years ago we were in the official "extreme" category. So I need to know as much as I can about which trees can withstand some drought, especially the younger ones. This year I planted 270 trees, and in the two years before that anoher 100 or so, so I need to do a lot of watering. I can't water everything, and when it gets really, really dry, some of the older ones--those in the ground for 4 years or more--show stress. So it is very important to me to know just what might need watering.

Right now I have 600 feet of hose strung out, and a lot of trees I water with plastic one-gallon jugs that I carry in my suburban, and then hand carry to the little trees.

Yes, I saw the disagreement about Taxodium and Metasequoia. I have both here. One good thing about Taxodium is that it gives a good warning when it is under stress--its leaves begin turning brown and dropping off long before it will die. Two years ago I thought one might have been a goner, but it turned out to be just fine after I gave it a good soaking. Losing its leaves is a protection mechanism.

As for the metasequoia, they are a bit younger and I don't have as much experience. Will they give me fair warning?? Anyway, two years ago in the extreme drought, the older one did very well. But I have seen some planted in other places with severe dieback that year, that I assume--I really don't know--was from the drought. Maybe this year I have been more careful to water the other one, in the ground 4 years, than I have to be--I wish I knew.

--spruce

I get the feeling feeling DR's are a bit more intolerate of strong, continental weather extremes, preferring a more even, climate. ( They are also very sensitive to road salts if that is an issue. ) A few years ago we had dry, hot winds in early April as the leaves were just developing--after a couple of days they looked as though they were blasted with a flame thrower--as the timing of the drought, frost, or heat is critical for them. The Taxodium did not seem troubled by the premature heat. They each have their own niche, the BC's will take hot, burning sun better, and the DR's are better under more shaded conditions. Probably both as tolerant of saturated or ocassionally flooded grounds.

Your horticultural upkeep is astounding and inspirational! Take care.

Bald Cypress are puzzling as to how to rank them. Know of several examples of established trees down here on dry hill-tops that are not watered and doing fine (20' or higher). But for the first 2(?)years, mine haven't established. Have two at year 5 that seems good to go and 2 more at year 3 that am leaving on their own and monitoring.

I know when I first started buying these trees as bare-rooted sprigs in the mail, I had a much higher mortality rate with the BC's compared to the DR's right after transplanting. Still, I think BC is one of top 5 favorite trees (native or otherwise). At first seemed somewhat slower to get established in ground compared to DR's (which were fast from the get go), but then mine took off!