Prescott Plant Hardiness zones

When thinking about your garden and landscape, it's common to want to grow and enjoy plants that you are accustomed to.  Either from where you most recently lived, or from where you grew up.  We all have that nostalgia for a familiar landscape.

But, one of the most frequent questions I hear from newcomers to the Prescott, AZ area is that they struggle with finding the appropriate plants that will not only grow, but thrive and become well established without a lot of fuss.

One of the core refence tools for gardeners and landscape design, is known as the USDA Plant Hardiness Zones.  There is also an index by Sunset Magazine, and then there are climate and heat tolerance zones as well.  Lot's of different indicators that can be helpful, but for this post I am going to focus on the USDA Hardiness Zones.

My advise:  Know and embrace your garden zone!

Keep reading for all the details.

There's no point in selecting annuals and perennial plants that aren't suited to your zone if you want a healthy and vibrant landscape that looks it's best with minimal effort over all four seasons. 

If, on the other hand, you prefer annuals for their bright colors and short-term summer beauty, no worries.  Feel free to indulge but know that you will be replacing those plants each growing season, or possibly bringing them indoors to a greenhouse and then back out.

​New USDA Hardiness zones

In the last few days the USDA announced that they had updated the zone maps for plant hardiness.  This was a response to climate change that we are all seeing, but it's also something they do periodically (every 10-15 years).  Most recently, these maps were updated in 2012.

I wanted to update you on what's changed, and what hasn't. 

I bet a lot you are curious and the headlines, of course, are focusing on the fact that many areas have gone up with this update.  That means that your average annual extreme minimum winter temperature is  now in a warmer 5-degree zone than it used to be.

To be clear, this doesn't refer to the lowest ever temperature reading in your zone, but the AVERAGE low temperature.  So, if you are researching or purchasing perennial plants for your landscape, you want to find varieties that are hardy to your zone # or lower.

​Prescott area zones

For example, Prescott AZ is mostly zone 7b (which has an average minimum winter temp of 5-10 degrees fahrenheit.  To find plants that can survive the winters here you want plants that are hardy in zone 7b, 7a, 6b, 6a etc. 

Remember, though, that plants not only need to survive the coldest temps but also the micro-climate in your particular little part of the area as well as the high temps and the amount of precipitation that you get (or provide).

If you live in Williamson Valley or The Dells, for example, it's likely that you're micro climate is very different than say downtown Prescott or areas south of that like Walker or Groom Creek which are at higher elevations and much more heavily forested.  Many things will affect your particular climate zone including your elevation, the type of soil in your area, the wind exposure, the size and number of trees on your landscape, etc etc.  

​did prescott zones change?

Okay, so back to what changed and what didn't.

It's fair to say that in general, we need to be planting and designing landscapes that take into account hotter and dryer seasons, and that these should be focused on water wise and drought tolerant plantings as much as possible.  This is just a pragmatic approach to conserving water resources and creating a garden that is more likely to be successful - healthy and sustainable.  Plus, it's just ultimately going to be a space that is prettier and more enjoyable.  And easier on the budget.

Having said that, if you want to know if you can begin planting slightly less cold hardy plants, you need to know if your plant hardiness zone has gone up or not.  I did a little poking around for Arizona and here's what I found:  Prescott overall hasn't changed, still generally zone 7 and mostly 7b.  The only major city in Arizona that changed was Phoenix.

• Flagstaff:  still zone 6A
• Prescott:  still zone 7b
• Sedona/Verde Valley:  still zone 8b
• Phoenix:  went up from zone 9b to 10a
• Tucson:  still zone 9b​

General guidance

Remember that you can also research your heat and climate zones for plant selections to find that sweet spot.  But ultimately, every property is a unique combination of factors that mean you have to adjust your selections beyond your zip code or region.  

Also a warning - for the majority of websites, articles, and books that talk about Hardiness Zones, just be aware that most of them are going to still be referring to the old 2012 USDA data/maps and it will be a while before they are all updated.  

To wrap this up, I am going to share two resources that are very worthwhile reading if you want to dive deeper.

• Arizona Climate Zones for Growing Plants - UofA Cooperative Extension
• USDA Plant Hardiness Zone Map - with zip code search​

still not sure?

Still got questions?  Not sure what your micro-climate situation is?

Did you know that The Whiskey Porch does landscape and garden design and consulting?  We can help you figure out what are the best plants for your little part of Prescott.
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Landscape Design Services

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Thank you for following along with me.

I hope you found this interesting, and possibly helpful.  Let me know what you think in the comments below - I read them all!

Peace & Contentment,
~Miriam
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