Hardiness Zones Creeping North

So I've been reading about the Plant Hardiness Zones creeping north, here in Trenton, SC, we are still zone 8. However, eventually we could end up a zone 9. What does this mean for growing fruit trees and berries? There are a variety of things I can't grow here already because it doesn't get cold long enough to set fruit. What are some safe fruit bets for zone 8a that could become zone 9 in the next 10 years? Are there any cherry varieties?

Here's an article about it:

http://www.wunderground.com/blog/JeffMasters/new-usda-plant-hardiness-zone-map-for-gardeners-shows-a-warming-climat

Well, I don't think that our weather is gradually getting hotter all the time because while I have noticed that there was an above average winter in my area this year with a few shifts in wild fruit production, just 3 years ago we had a below average winter and even got a frost with a very tiny bit of snow (about 1 inch or so and it only lasted about half an hour), which is slightly unusual. Thus, I think we are getting almost a curve of different weather patterns that seem to balance out each other. Also, the area I live in seems to go through these cycles because about 17 or so years ago there was another below average winter and there was nearly a blanket of snow and there was another small snow in between then and now. I don't know if this helps at all with selecting fruit trees and berries as these are just my observations and I'm not quite an 'expert' on this topic, but you may want to try a few trees or berries that can withstand the heat better and see how they do.

Here's one way to tell the difference between zone 8 and zone 9: loquat trees. If the loquats have fruit on them in April, it was a zone 9 winter. Last year, I could find bearing loquats in Augusta and Columbia. This year, no such luck.

The difference between zones 8 & 9 are subtle, since both will have hard freezes. With zone 9 though, you will have a lot more making it through the winter than if the lows drop into the teens a lot, like a typical zone 8 winter. This past winter was a little unusual, in that the cold hung in through March and even plants that do well in cool weather were having trouble. I've never had such a poor crop of peas and potatoes as I had this year. Usually, by April they are in good shape and ready to start producing. This year when April came, they were barely emerged from the ground.

For deciduous fruit trees, it's not really the zone that matters (i.e., the absolute lows during the winter), but the number of chill hours. They need their winter rest, and that is determined by the number of hours below 45F that are racked up in the winter months. When you buy fruit trees, a good grower will be able to tell you the number of chill hours the tree requires. You can then look that up for your particular area (here's a link to some CSRA stats), and then select varieties that will be OK for your area. With the climate changing, there may be fewer chill hours in 10 or 20 years, so if a tree needs 1200 and your area only averages 1000, better ditch that selection and go shop for one that only needs 800 or fewer. I believe there are some cherry varieties that can produce with as little as 800 chill hours. You may also want to try Krauter Vesuvius plums, it's either a small plum or a big cherry, and this year the ones in Augusta seem to have a nice crop of fruit on them. I have a few that I started from cuttings last fall. I'm just a little disappointed by the low percentage of cuttings that actually took.

John Elliott wrote:Here's one way to tell the difference between zone 8 and zone 9: loquat trees. If the loquats have fruit on them in April, it was a zone 9 winter. Last year, I could find bearing loquats in Augusta and Columbia. T

The only Loquat I had, a very small one, was apparently killed by the ice storm because it never put back out. Thanks for the recommendation on the cherry/plum tree. Will look into it. Do you keep any varieties of blueberries that you'd recommend for this area. I don't know if I just got bad plants, planted at the wrong time, or wrong location but a few years back (before I knew anything about permaculture) I planted a handful of blueberry plants in North Augusta and none made it through the winter.

I got my blueberries at Cold Creek in Aiken and when I first put them in, they did so-so. Then I discovered what you have to do to really have success with them here -- hugelkultur. Or the next best thing to hugelkultur, digging in a lot of rotting wood around the bushes during the winter. Collect up all the oak branches that fall in your yard and drive/dig them into the dirt around your blueberries. Then collect up all the fallen pine cones and shred them up to use as a surface mulch (about a 2" layer). I've been doing that for going on two years now, and I actually have volunteer blueberry plants sprouting from parents a few feet away. That is how I conclude that they are thriving now and not "just surviving".

I don't really go by zones that much. We are supposed to have shifted from 7B to 8A with the changed map, but the last two years have been colder than many in the last 20. The real damage is done here by late freezes that wipe out the buds and sometimes the more delicate trees like figs. Personally I don't think it is so much climate change as weather cycles. We are going through similar weather conditions both locally and in the Atlantic and Pacific as there were in the 1950's. This means long multiyear droughts broken by occasional rains for a season. The climatologists here are predicting another 6-10 years of the same.

Last winter everyones figs and rosemary died even though they just pushed our hardiness zone from 6b to 7a. I feel like I am too greedy and wanna grow everything. How permaculture friendly is a tropical greenhouse up north?