Attn: Master Gardeners ~~ Help! So confused!?

Question

I found 2 web sites discussing "zones".

http://www.sunset.com/sunset/garden/article/0,20633,845238,00.html

and

http://www.arborday.org/treeinfo/zonelookup.cfm

What is the difference between a "climate zone" and a "plant hardiness zone"?

When I am buying plants or bulbs at the nursery and the instructions talk about zones, what zones are they referring to? "Climate Zone"? or "Plant Hardiness Zone"?

Thanks in advance to everyone for your EXPERT advice.

Answer 1

Plant Hardiness Zones refer to the average low temperatures whereas Climate Zones take into account all of the other variables that affect plant growth and sustainability. Moisture, soil, winds - all of these will affect your plants.
The tags on plants in a garden centre refer to the Plant Hardiness Zone, and most good chains of gardening supplies will only stock those plants that are hardy to your region. I like to push the limits, though, and will buy through mail-order sources just to make my garden different and more interesting. lol
Happy Gardening!
And thanks for including links in your question. I didn't know about Climate Zones before, and will investigate them further!

Answer 2

Sometimes an area will have their own ranges or climate zones, like the one provided by Sunset. It is more detailed for the area that you live in. See all the details provided in each specific zone or location?

The National Arbor Day Hardiness Zone is a little more general for the U.S. There are a lot of hardiness zone maps, but these should almost all have the same numbers (some with A's and B's).

When you buy plants in a nursery, they are probably referring to the hardiness zone.

The climate zone is the typical climate/weather one can expect in the area/region. The hardiness zone is a temperature/weather region where certain plants can survive. So, in a sense the same thing, both weather/climate related.

Answer 3

Usually the labels on plants and bulbs will have the more general zone info like what you see on the second link, for example Zones 5 to 9. They give you a pretty good general idea of what plants will survive in the average temperature range of that region.
The Sunset zones are more specific and take into account the microclimates within the larger zones. For example, I live north of San Francisco, in Zone 9. But because different parts of my immediate area have varying degrees of weather differences because of the effect of the Pacific Ocean, I am in Sunset Zone 15, while other nearby locations are in Zone 14.
Almost every plant label and catalog description will use the other system, so that's likely what you need to consider.

Answer 4

They almost always refer to hardiness zones ... But, often, they are very " liberal " with their zones ... a plant may be zone 5 , but is sometimes listed as a zone 5 .... When you find a plant you like
at the nursery, LOOK it up in any reputable plant guide first...

I had a friend buy Purple Fountain grass three times , only to lose it everytime to winter cold .. It is zone 6 , at the max, but the plant tags all said zone 5 ... ( I wished she had asked mr first ,,, )

I have another friend that goes to buy plants , and when she finds what she likes , she simply looks it up in the books for sale , right at the nursery ... a good idea ...

Answer 5

Not really an expert, more of a gardening hobbyist. The identification lables found on items purchased in the nursery or ordered on line through gardening supply companies identify the plant hardiness zone.

Answer 6

I'm no "master gardener" but in plain english...you can't grow tomatoes in a location where it is going to be cold/frosty everyday. They need sunlight and hot temps to grow.
The information on your plant is telling you that the conditions from July - August are best to plant that item for you to get the best production be it flowers or veg/fruit