Changes in zone hardiness maps

[Orchidzrule]

Rob

I guess I would never use these hardiness maps as an indicator of global warming. You're right, more factors are being taken into consideration when they publish these things. Actually, I think the reason I got bumped up a zone was because they now recognize the heat island effect of living in a big city. I live smack right in the middle of Mpls and it's always warmer here than 10 miles out in the burbs.

The thing that is the hardest on my garden is the lack of snow cover in the winter now. I won't mulch for winter. I know I should, but I won't do it. Since my garden is SO full, I almost welcome some of the winter losses. It opens up some more room to try something else. I know, that's sick, but true.


Enough from me.

Oh, Kev, I could never get enough of you!

Seriously, the point about heat islands created by cities is impressive. A good friend of mine is a fairly keen, albeit novice, gardener. He lives at the extreme NE corner of Winnipeg, whereas I live in the south part of the city, although not way out. He always seems to get colder overnight temperatures at his house than I get. He'll see heavier frost, and especially in early winter, more accumulation of the white crap in a snowfall than I see. I have another friend who lives right downtown and his apartment still has live impatiens after all mine have been killed by frost in fall.

I'm not sure, though, if hardiness zones take this into effect--these are more along the line of microclimates than real climate zones.

Cheers,

Rob

[TundraKev]

Rob

I think they do take the heat island thing into account if they are big enough. On one map I saw, the Twin Cities was very clearly designated as a zone 5. All the surrounding area was still a zone 4.

Microclimates are very cool and strange. I know I have them in my own yard, but I've never really taken the time to figure them all out. This year, two clematis tangutica next to my house didn't make it. A couple of others (same clematis) about 15 feet away and next to a fence came through just fine.

Tis all very strange.

[Piper]

Kev,

Would you consider the ones that didn't do well, 'micro-clematis'?

Julie

[TundraKev]

Nooooooooooo

Especially since they grew almost all the way to the top of my house last year. I have a 2 1/2 story house.