Note that this is the coldest area on his property. Its against a 6 ft high solid wood fence and the seedlings got no sun from early
November through mid February. Some areas really close to the south fence didn't get any sun until mid March. They were all
snow covered for at least 6 weeks, some up to 9-11 weeks.  No protection was given to them.  All were first year seedlings
started in May 2000.  Soil is native loam mixed with a little sand in the first 3" or so.  The seedlings were planted in the ground
in June 2000 from the seed trays. The average temperatures were:

Nov...AvgHigh 9.1C...AvgLow 1.0C...MinLow -11.1C...Precip. 91mm
Dec...AvgHigh 2.4C...AvgLow -7.8C...MinLow -15.0C...Precip. 87mm
Jan...AvgHigh 2.0C...AvgLow -7.1C...MinLow -12.8C...Precip. 52mm
Feb...AvgHigh 3.7C...AvgLow -6.3C...MinLow -15.6C...Precip. 34mm
Mar...AvgHigh 4.8C...AvgLow -2.4C...MinLow -7.8C...Precip. 207mm(yes, 207 mm)

Here are Tim's results, made in April 2001:

Y. arkansana, 1 plant, 0 pulled.  Looks OK, it's still small so it's hard to tell.

Y. baccata (Rio Rancho, NM), 5 plants, 0 pulled, 4 are 100% green, the other in
another location is 90% burnt.

Y. baccata v thornberi (Nogales, AZ), 6 plants, 3 pulled, 2 are not that firm and
1 is firm.  All are 100% burnt.  1% chance of survival.

Y. baileyi, 10 plants, 1 pulled, 2 plants are 50-80% burnt, most are less than 20%
burnt, some are almost 0% burnt.

Y. "colorado" (Colorado Springs,  CO), 19 plants, 0 pulled, little to no leaf burn, look good.  Probably Yucca glauca.

Y. brevifolia (Caliente, NV), 1 plant, 0 pulled, its very tiny, hard to determine if its OK or not.  The freeze/thaw cycles pushed
the plant out of the ground in mid March and I had to replant it.  The roots didn't look as good as the leaves. I think this will
die.

Y. carnerosana (Brewster Co, TX), 19 plants, 13 pulled, only 2 are still firm to the tug.  All are 100% burnt.  0% chance of
survival.

Y. elata (Sonoita, AZ), 12 plants, 0 pulled, the best one is 10% burnt, 7 are 80% burnt, the other 4 may not be elata (they look
like rostrata, but my field label says elata.  There may have been a mix up in the trays or something. Looks like one is a real
winner.  These "rostratas" are 100% burnt but did not pull.

Y. elata v valencia (Valencia CO, NM), 2 plants, 1 pulled, other hanging on with 80% burns.  10% chance of survival.

Y. faxoniana, 8 plants, 2 pulled, 4 look like crap and are 100% burnt, 1 has some leaf
spotting but is very firm to the tug and 1 is untouched!!!!  No burn, nothing, amazing the difference in this one.

Y. filamentosa "variegate", 7 plants, 0 pulled, all look great, some spotting on some of the leaves but pretty minor.

Y. glauca v gurneyi (Clayton, NM), 1 plant, 0 pulled, <10 % burn

Y. glauca radiosa (Cliff, NM), 11 plants, 0 pulled, 2 are 100% burnt, all are very firm to the tug, best ones are about 20%
burnt.  Look pretty good.

Y. glauca radiosa (Pinalino Mts., AZ), 8 plants, 1 pulled, 2 look in poor shape, other 5 are 20% burnt

Y. rostrata (Redford, TX), 8 plants, 7 pulled, the one which didn't pull is about 10% green still and is firmly in the ground, I'll
give it a 40% chance of survival.

Y. schidigera, 1 plant, 1 pulled.  Dead for a few weeks now.

Y. schottii (Santa Rita Mts., AZ), 11 plants, 4 pulled, 6 others didn't pull but aren't that firm in the ground.  One is firm in the
ground and is 10-20% green, I'll give it a 50% chance of survival.

Y. torreyi (Anthony Gap, NM), 13 plants, 13 plants pulled.  These were some of the earliest plants to start pulling (Feb.).

Y. whipplei (Tehachapi, CA), 15 plants, 13 pulled.  All died in cold micro climate but 1!!!!  One is still green with only 10-20%
burn.  A real surprise.  The other in the warm micro climate is doing great and I think it's already starting to grow??

Dasylirion wheeleri, 9 plants, 6 pulled.  2 in the cold micro climate did not pull but don't look that great.  They are yellow near
the spears and green on the outer leaves.  10% chance of survival.  The one planted in a warm micro climate is doing
fine with no yellowing.

Summary:

Elata blows the doors off all of the trunk forming species (except for glauca gurneyi).  Torreyi seemed to rot first. That one
faxoniana is some sort of cold lover or something.  Its amazing.  Same is true for a single whipplei. I was very disappointed in
schottii and rostrata.  Many people on the east coast USA rave about these, but failed a long time ago.

Tim Behan.

Copyright 2001-2005, Tim Behan & Benny Moeller Jensen

If you want to read more about Tim's Yuccas look at Tim's hardiness web page.