Since the bulbs can live year round in the soil, including in the heat of full summer, I'm not sure that argument holds water :-) It's true that warm soils and soil moisture encourage root growth but that's exactly what you want to have happen in the fall and why the bulbs should be planted early enough to develop a good root system before the soil becomes too cold. At most you may get a bit of foliage growth if the soil is excessively warm but I doubt that is very likely in your location. And the bulbs will grow and perform in spring as nature intended. Spring flowering bulbs get planted as early as September in my area without any problems.

Oddly enough, my very first question on Gardenweb (back in 2001, I think) related to bulbs - specifically the fact that mine were seemingly romping away above ground in October. I was given the sensible advice to ignore them - it is perfectly natural and the bulbs would be OK. They were.

I have heard a few suggestions regarding fungal issues and tulips being planted early...which I also ignored - mine went in weeks ago.

Thanks, everyone. Another question about the planting of flower bulbs: when I see recommendations to plant a bulb 4" deep, does that mean 4" to the top of the bulb, or to the bottom of the bulb (i.e. the total depth of the hole)?