Gardening by the Map

This is old news for some, but in case you haven't heard, the USDA released a new growing zone map in January. Many gardeners found themselves now residing and gardening in a zone warmer than they were previously. I thought that would be the case for me, but it wasn't.

I've been in Zone 5b for as long as I've been a gardener and that's where I am still. Though everyone around me jumped to Zone 6a, I'm still in a little pocket of Zone 5b and I agree with this. There's no way my garden is Zone 6.

Click here to see a larger version.
I'm in Paulding County - in the blue part.

For years, gardeners have lived and died by the growing zone ratings each plant is given, based on the highest and lowest temperatures a plant can typically survive. We read it and if it says the plant is only hardy to zones warmer than ours, we don't buy them, right? HA! I mean, who hasn't tried to push the limits by growing a plant that isn't supposed to live through the winter or summer where they live?

The sources of information for those tags aren't always in agreement with each other either. For example, when I first planted Origanum 'Kent Beauty' many years ago, the tag said it was hardy to Zone 6. But I was in love with it and I had a warmish spot on the south side of our family room where I knew the crocus bulbs emerged earlier in the spring, and the mini roses leafed out there before they did at any other location on our property. I had to try it.

Origanum rotundifolium 'Kent Beauty' ~ July 2011

It performed well that first summer and I was a happy girl. But after one winter, it didn't return the next spring. A couple of years later, I tried again. This time, the tag said it was hardy to Zone 5, and indeed, that second 'Kent Beauty' has returned for several years. Did anything change? No. Plant tags differ, and perhaps the winters were more mild or we had more snow cover. In any case, I consider this plant to be marginal for me, no matter which zone the tag says, based on my experience. Win some, lose some. In this case, I'm winning. (So far.)

A lot of data was used to come up with this new map - data that wasn't used in previous incarnations of it. So this new one should be more accurate. But experienced gardeners know what will grow in their gardens and what won't, regardless of what the hardiness maps say. They know that it's more than zone that determines a plant's viability.

Click on image for a larger version and click here for an interactive map.

This new map, just like the old one, will help the novice gardener by giving them an educated guess as to what their plant choices are. But they should also consider soil, protection from wind, sun exposure, moisture, and proximity to buildings, among other things. Nearly every garden has micro-climates that allow them to grow outside their zone.

Take the new map under advisement, but realize that living things are always subject to the effects of many different factors. It's only a guideline, not gospel.

For more information, visit the USDA website. Did your zone change with the new map?