Z - Zone

Z is for Zone.  

Do you know what planting zone you're in?   You need to!

The USDA Plant Hardiness Zone Map (maps are based on 30 year averages) is where you'll find out what zone you're in, and therefore which plants will likely thrive in your area.  From the site you can then link to a map of your state, or input your zip code to see your zone number. The higher your zone number, the warmer your average low temperature is in winter.

http://planthardiness.ars.usda.gov/PHZMWeb

The numbers below the zone is the average extreme low temperature.  My zone is 8b, and my low is shown as 15-20 degrees.  When I lived in California my zone was 9b, low temperatures 25-30.  As a child, if a freeze was predicted, we would mix milk, sugar and a few drops of vanilla in a pie tin to leave outside overnight.  In the morning we had "ice cream" for breakfast!

When I first moved to Southern Oregon a scant 7 years ago my town was zone 7b.  My frost dates (the average date of the last and first frosts, an important consideration when planting out transplants and seeds) have changed as well, the last date moving from May into late April.  What's doing on?  I came to a shocking realization, my zone is warmer due to climate change!  Could it be?  Yes, as I found out.  https://www.arborday.org/media/mapchanges.cfm

However, the USDA claims, "changes in zones are not reliable evidence of whether there has been global warming."  Sorry to be a skeptic about that, but our Administration recently removed dozens of online resources on "climate change" from the EPA (Environmental Protection Agency) website, epa.gov, and actually deleted those words 15 times on the main page alone, so I don't buy it!  It's like not telling the Emperor he's naked.  Not mentioning it doesn't make it not true!  (You can access the  information from an older version of the main page though, so not all is lost!)  https://19january2017snapshot.epa.gov

Now what?  You know your zone, how does that help you plan your garden?  This is where your research comes into it.  Not a lot, people have done most of it for you, and the results are all on plant tags, or online.  Before you even set foot in a nursery, before you set your heart on a specific plant, find out what zone it's recommended for.  Don't assume the nursery only sells what works for your area, it will sell whatever sells.  

Let's say you want a lavender plant.  You can go to online merchants with large selections of plants and read about them.  Mountain Valley Growers (my go-to herb information site) has 25 different lavenders!  Click on each and see the zone ratings.  French lavender is 8-11, on the edge for me, and the only French lavender I did grow was killed in an extra cold snap one winter.  White Grosso on the other hand is for zones 5-11, a much better choice, and one I purchased last year.  

I'd love a bay tree in a container.  I grew up with bay trees.  But, what is this?  Bays are zone 8-11, and need protection in cold winters?  How can that be? Turns out the bay commonly offered in nurseries and online is the Laurus nobilis or Greek Bay.  What I want is the Umbellularia californica, California Bay Laurel, a native to California and Oregon.  Perfect! That must be what we had in our yard, and found growing all over the foothills in the area.  It's the only species in its genus.

Check the tags on each plant you are interested in, the zone will be shown. If it isn't, don't buy it until you look it up yourself.  That will save you the cost of a dead plant, and the frustration of having to plant another in its place.

Lewisia 

Z was for Zone.  And now we've come to the end of our A-Z of Gardening.  I hope you've had fun, I know I did!