zone label issues

I need help to understand what is going on. Are there more than one zone maps? And if so, how do you know which one is referred to by the tag or the website?

Here's why: take for example, showy evening primroses-- the pink and yellow ones. I have a book that says they are zone 5 hardy, but the tags on the home depot plants says they are zone 4 hardy. Who do I believe and why the discrepancy? I really want these flowers, but maybe I shouldn't plunk down the money for them if they won't make the winter. I have some yellow ones and they do just fine (more than fine-- 6 plants turned into 43 in a single season).

Same for Russian sage, for example. I have seen it listed as zone 5 hardy, but then there are places online that list it as zone 4 hardy. What is up with that? You see it growing here (on the zone 3/4 break-- or maybe more to the south in clear zone 4,) but maybe they are planted as annuals (except they are really big!) I am gonzo confused about this. If I get it, does that mean I have to bring it in every winter?

Also what about flax (lineum with the little blue flowers.) I am seeing zone 5 hardy most places, but then there are some that say zone 4. I bought a plant that didn't have zoning on the tag and looked it up only to see zone 5 (darn!)

So what does all this mean and what are you supposed to do?

Thanks!

Try contacting your local county agricultural extension agent. They have ties to the state colleges with lots of information, including Master Gardeners. Many areas within different zones have micro-climates in which some plants will thrive even though they are zoned for a different zone. It is confusing to a new gardener, however, the experts (ag. ext. agents) should be able to help you with this.......your tax dollars at work!!

The problem is there's no universal reference that lists the hardiness for all plants. Since there are multiple sources of info for any given plant, you're going to find some variation in what's listed. As bugme suggested your extension office can probably help you out with what will really work in your area, and you can also take a look at local parks, neighbors' yards, etc in your area--if things are working for them then chances are you'll have luck with them too. And google the plant and look at the hardiness that's listed on a variety of websites--you may find that the vast majority list it as one zone and just a couple sites list it differently--if that's the case then it's more likely (although not 100% guaranteed) that the hardiness listed by the majority of sites is closer to right.

Wow. Thanks for your answers.

I have also been told that some individual plants are more hardy than others and that sometimes an odd individual (say a zone fiver) will make it here if you mulch the heck out of it and it is "protected" or by a heat source (like a dryer vent) or on a sunny south side lee of the wind. Is this true?

I'd only take the risk if you don't mind losing it. Your dryer probably isn't on all night long. Some plants near the foundation can survive a colder zone but often the eaves prevent rain from getting to them.

There is some truth to that, there is always some natural variation within a given species. For example, if you're trying to grow something that is borderline hardy in your climate, your best bet is generally to buy one that's been grown at a nursery in your area vs one that was grown in Florida or somewhere else a lot warmer than you--the ones at your nursery may be slightly hardier since they've been bred in your climate and the less hardy ones would have been killed off. And you can certainly have warmer microclimates in your yard and take extra measures to protect things and sometimes squeeze an extra bit of hardiness that way, but as pirl pointed out there's still a risk...so if it's a plant that's expensive or hard to find then I probably wouldn't trust leaving it out in the cold.

Thank you again for the information. I am learning so much on this site and I really appreciate the folks who take the time to help me with my botanical education!

Honestly there is so much to learn, I will be at this for years before I feel real confident answering somebody else's question!

We're all here to learn and to help others. We were all new to gardening at some point in our lives and gardeners are so good at sharing their knowledge.

Good luck to you and your gardens.

Rubia, there is one additional reason. Quite a few places carry replacement guarantees on plants. They would rather err on the side of caution if a plant MIGHT be hardy in zone 5, they say it IS hardy to zone 6. Fewer iffy plants to replace if they don't make it. I am in zone 8b/9a cuz I am on the border. There are places in my yard that I can grow zone 9 plants because of the microcosim created by trees, fences the house. Likewise there are places where those same plants may not survive. Additionally, a plant may freeze to the ground here and return in the spring, but the zone listing is saying it won't freeze down in zone 9 or above. It sort of boils down to a CYA philosophy of doing business.

I never thought of that! But it makes perfect sense to me. So maybe I will get those primroses and save the receipt!

Now I feel a little braver taking the chance.

Just make sure the place you buy them from does indeed have a replacement guarantee. Otherwise, spring for 1 plant this year and see what happens and read up on what the plant requires to give it the optimum growing conditions.