My outdoor thermometer is broken so have no way other than empirical evidence to confirm, but I don't think it got all that cold here in Shoreline. Maybe 20 or slightly below. I am seeing very little evidence of significant cold damage in my immediate area and a walk this afternoon in Edmonds confirmed most plantings there came through with flying colors.

Marginal large leafed hebes look pretty battered but the smaller leafed ones are clean as a whistle. Most phormiums looked OK if slightly flattened from snow loads. Common broadleaved evergreens - Viburnum davidii and tinus, nandina, pieris, choisya, abelia, escallonia, Arbutus unedo, most ceanothus - look untouched. A bit of burn on a sasanqua hedge but it is sending out a new flush of flowers. Upright rosemary fine; prostrate rosemary not so fine :-)

The only fatality I can confirm in my garden is a coprosma planted in a container, but I knew that was going to be a marginal plant at best. It did manage to last for three seasons, though. All my pittosporums seemed to have made it through just fine...none are even showing any significant leaf drop.

I live in North Lakewood (my address is Arlington) which is pretty much right in between Marysville and Arlington. Our lowest low was 5* but I heard it was colder in Arlington proper. My pittosporum looks really sad, I hope it will recover.

Edmonds has burned up cordylines, escallonias etc.

13 in Sequim, 20ish in Olympia.

Here is some regional data from what was the coldest night for most of us. Numbers indicate high, low, precipitation, snow depth.

000
ASUS66 KSEW 210028
RTPWA
WASHINGTON STATE TEMPERATURE AND PRECIPITATION TABLE
NATIONAL WEATHER SERVICE SEATTLE WA
428 PM PST SAT DEC 20 2008

:
:MIN TEMP IS THE 18 HOUR MINIMUM TEMPERATURE ENDING AT 10:00 AM
.B SEA 1220 P DH17/TAIRZY/TN/PPD/SD
: :ID STATION AFTN MRNG 24HR SNOW
: HIGH LOW PCPN DPTH REMARKS
:PUGET SOUND
SEA :SEATAC ARPT : 26 / 14 / T / 2 :
SEAW1 :NOAA SANDPNT : 27 / 19 / T / 1 :
: BELLEVUE 26 / 15 / 0.00 / +
TCM :MCCHORD AFB : 25 / 10 / 0.00 / + :
PAE :EVERETT : 22 / 10 / 0.00 / + :
PWT :BREMERTON : 23 / 12 / + / + :
SHN :SHELTON : 24 / 15 / 0.08 / + :
TIW :GIG HARBOR : 26 / 20 / T / + :
: :NORTHWEST INTERIOR
: MAPLE FALLS 12 / -7 / 0.00 / 16
BLI :BELLINGHAM ARPT : 20 / 11 / 0.00 / + :
FHR :FRIDAY HARBOR : 25 / 8 / 0.00 / + :
CLM :PORT ANGELES : 22 / 18 / T / + :
NUW :NAS WHIDBEY ISL : 22 / 8 / 0.00 / + :
AWO :ARLINGTON : 19 / -6 / 0.00 / + :
: :SOUTHWEST INTERIOR
OLM :OLYMPIA : 24 / 7 / 0.11 / + :
CTRW1 :CENTRALIA : + / + / + / + :
KLS :KELSO : 28 / 23 / + / + :
VUO :VANCOUVER : 28 / 27 / 0.00 / + :
: :WASHINGTON COAST
UIL :QUILLAYUTE : 27 / 21 / 0.04 / + :
FORW1 :FORKS : 25 / 18 / 0.08 / 4 :
HQM :HOQUIAM : 25 / 23 / 0.01 / + :
: :WASHINGTON CASCADES
SMP :STAMPEDE PASS : 6 / 4 / 0.05 / + :
PKWW1 :PACKWOOD : + / + / + / + :
: :NORTHEAST WASHINGTON
DEW :DEER PARK : 4 / -17 / T / + :
GEG :SPOKANE : 4 / -18 / 0.01 / 16 :
: :NORTH CENTRAL WASHINGTON
OMK :OMAK : 8 / -3 / 0.00 / + :
: :EAST SLOPES CASCADES
EAT :WENATCHEE : 6 / -7 / 0.00 / + :
ELN :ELLENSBURG : 11 / -6 / T / + :
YKM :YAKIMA : 14 / 8 / 0.02 / + :
: :CENTRAL BASIN
EPH :EPHRATA : 27 / 1 / 0.00 / + :
MWH :MOSES LAKE : 10 / -4 / 0.00 / + :
: :SOUTHEAST WASHINGTON
PUW :PULLMAN : 7 / -5 / T / + :
ALW :WALLA WALLA : 10 / -2 / T / + :
: :SOUTH CENTRAL WASHINGTON
PSC :PASCO : 31 / 1 / T / + :
HMS :HANFORD : 12 / + / + / + :

We were -13.7 C which converts to 7F. I have damage to one rhodie as well as many marginal plants. The last heavy, wet snow we got broke branches. I'm glad it's gone!!!!

Here is a link that might be useful:

And Edmonds also has a lot of cordylines and escallonias, etc. that are not burned up :-) There are microclimates in every gardening situation in all locations and it is risky to make blanket statements about minimum temperatures and extensive cold damage when every situation may offer different conditions. The extent of the snow cover can play a role also.

Ron, you seem to like to be the voice of doom and pessimism when it comes to issues of hardiness and plant damage. Why is that? Gardening should be a very hopeful and uplifting activity, full of promise for the future, and you seem to want to focus on all the negative aspects. It's kind of a downer. Mellow out!! Another growing season's on the way :-)

If someone heeds a warning not to plant something in the first place that's likely to freeze, then they won't put themselves in a position to be let down when it does. But then there are people like me who have to plant not-fully-hardy plants anyways knowing I will lose some. It wouldn't be hard to argue that my way doesn't make any sense either.

Crisped Escallonias hmm. This reminds me of something that irks me about the way Seattle area nurseries market plants. I see Grevilleas, Leptospermum, Callistemon, Acacia and others marketed very conservatively with dire warnings that they aren't fully hardy, while equally tender selections of Hebe, Cistus, Ceanothus and Escallonia are sold by the hundreds every year with no such warning. What's up with that????

It got down to 2 degrees F here along Mt. Baker Hwy just outside of Bellingham city limits. I've seen some damage on parts of plants, but, so far, no clear deaths. My pierises (sp?) seem fine. But my Pampas grass looks like Cousin Itt. The rhodys all look healthier than ever, though.

What interests me about this year is the extent of damage. Failure of plants expected to live long periods of time in this area without such troubles is as noteworthy as apparent success with those thought not to be hardy here. It's all facts worth noting.

Some people involved in commercial horticulture appear to have a habit of mis-representing the potential of specific plants - both the potential to loom large in time and overwhelm a planting space and the potential to burn up when a cold winter comes. Nursery listings routinely understate heights and overstate hardiness.

The facts are what they are and discussing local failures of plants represented as "fully hardy" is not being pessimistic, it's being realistic. I'd think when numbers of plants are sold by outlets as reliable and then go down in customer's yards and commercial installations later that a degree of trust will have been lost. I certainly encountered some of this wariness during the years I worked in local retail outlets.

With good reason. A plant that dies back at 15 degrees F. is not "fully hardy" in most locations here.

What we generally regard as "cold" here ain't nothing compared to what they are currently experiencing in other parts of the country! An Internet friend from Iowa reported overnight lows of -27F. Yowza!!

Here is a link that might be useful: The midwest's big chill

In north Edmonds, 400 ft, we got to 8 F the weekend BEFORE the big snow. There was still just a little snow left from the previous week.

Assuming everyone has accurate thermometers, the variations are interesting. Might have to do with air drainage (and other factors) much of the time. My green cordyline has a collapsing tip the leaves below aren't as bad - so far anyway - whereas the one down the hill (which might be a purple one) I've mentioned is a pile of mush.

7-8F is defintely well below tolerance for phormiums, cordylines, many hebes, cistus and so on. That's getting down near 1990 temperatures.

Somewhere I drove by a chocolate brown evergreen clematis. The one across the street looks pristine. I've gotten the impression these start to have problems around 10-15F; there may be a range of variation between cultivars or even seedlings (the latter is certainly appears to be the case with eucalypts, with siblings even seeming to range rather widely in hardiness).

BBoy is in zone denial. He posts zone 8. If the zone 8 plants he buys, dies, it's his fault.

16 degrees in this yard. Lots of damage. Ice was too heavy. Eucs are freezer fried. Praying many plants come back from trunk or roots when it warms up. Had some other zonally challenged plants that are now dark brown and withering.

Every night lately has gone below freezing. Always ice in bird baths. Heavy frost every morning. Cold out in daytime. Plants don't like this after the arctic blast.

Evergreens are browner. Just an icky time of year. Going to be pruning a lot today, all the willows. Have to get a bucket truck service to take the snapped
shredded branches off the top of the giant curly willow. The rest will be done today with ladders and pole pruners and hand pruners.

Times like this I'm glad I overplanted because I've lost so many trees.

Have 3 Oregon myrtles, now 3 years in ground but still small, that I'll be transplanting from the back south fence area, now too shady, to spots where other trees croaked.

10-20 degrees F. indicated for USDA 8 is an average, not the coldest it gets. If you're thinking the temperature ranges assigned to each USDA zone are the lowest temperatures - a common mistake - you are wrong.

Some winters here get to 10-20 degrees F, a few get colder and others are warmer. It's an average.

I still say there's no such thing as a zone 8 plant, or any zone plant. Various plants will be able to tolerate different USDA zones in different parts of the country (even the state). You don't define a climate based on what you're able to grow in it; it's the other way around.

I agree Ian. I think there is also no such thing as "This plant is hardy down to xx degrees". 15 deg for a few hours only on one night of the year on a dry week is vastly different from 15 deg for many days, and if it's right after a wet period.

Bboy I had a theory about those cordylines. I'm guessing it's mostly the water that collects in the crown, then freezes for an extended period, so I wonder if they maybe couldn't survive an extra 10 deg colder if I tied the upper leaves up for the winter to keep the crown dry. What do you think?

- Tom

Dotty I think we might have beat you, apparently we broke the record one night in December. -20 C I think that's about -4 F. What with the amount of snow and ice I've got a lot of damage, the Hydrangea in the front has a lot of snapped branches and it had been tied up, some of the Rhodos the same, parts of the garden are still under snow. The birds got into my pots of Hellebore seeds scratching the grit off, so I imagine they're history usually they're up by now. Roses have broken canes, other plants have been flattened. I haven't seen a winter like this since the 60's. I guess thats enough whining for now. A

Dang, that's cold for around here. How far from the water are you?
- Tom

How far from the water am I, well if I walked up the road a block crossed the road and climbed down a bank I'd be standing at the edge of the salt water estuary. Our winters are usually quite mild with the exception of a couple of weeks of low temps the end of january beginning of february, some winters we don't have snow or so little it's not worth mentioning but we do have a LOT of rain most winters and early spring. A

9 degrees F here in west Oly, two different nights, the first one the weekend before the big snow, so nothing was insulated by snow cover.

I don't really have any damage so far. We'll see in spring how things do.

A wide range of minimum temps is not unexpected, as everyone has a different kind of thermometer, placed differently. Mine is under a northeast-facing deck, so it's actually a bit sheltered and tends to read high in winter. I moved the sensor closer to the edge of the deck during this cold spell as it was too sheltered. That suggests that it was actually colder than 9 degrees, and I'm in a bit of a banana belt for my neighborhood. Often I'll have no frost when a block away everything's an ice rink.

The lowest temperature I saw on my thermometer was 17* F. It was during the day so I'm sure it was colder at night.

Hebe 'Eddington' is the only one entirely blackened and defoliated. I'm hoping it will come back from the roots as it was an outstanding bloomer. Clematis cartmannii 'Avalanche' and armandii 'Appleblossom' both have some damage. I've got a variegated Jasmine that defoliated but my Tracheleopermum is fine with light damage. Gardenia 'Klein's Hardy' is also just damaged not killed.