Tooele Transcript Bulletin – News in Tooele, Utah
image Frost tender plants, like the blue potato shrub, must be overwintered in a warm space.

February 22, 2018
How to know what will grow in our area

In gardening there is a direct connection between experience and wisdom. This is when you try a new approach, or plant a new variety, and see how it goes. This is learning by “trial and error.” It’s extremely effective, because it can be so expensive! There’s nothing like losing your investment of time, or hard-earned money, to drive home the lesson and make it memorable.

Instead, I prefer the indirect experience model, which is learning through shared experience of others who have learned costly lessons and share their wisdom with you. You could call this the “wisest wisdom,” because learning is accomplished through what others have already invested or done.

A lot of costly mistakes occur in gardening by choosing varieties or species that either won’t survive, or if they do live, won’t flourish. Fortunately, there are lots of readily available tools, as well as some general “situational awareness” of our growing conditions here, that will greatly increase you getting it right the first time when it comes to planting choices.

The number one factor to consider is cold hardiness. Just because something is sold at the local retailer doesn’t guarantee it will do well here. This is especially true of large retail chains. Their buyers tend to be regional or national, buying in large lots that will work for many areas, but not all. For instance, a common grape variety I see at chain stores is the seedless concord. Years ago, I bought a couple and planted them in my vineyard. They had grown for a couple of years, and were just about bearing age.

That season, however, the late Larry Sagers held a pruning demonstration at our home. When he learned that a couple of the vines were seedless concord, he told me that I should plan on losing them to cold. I silently disagreed, reasoning that they had done fine so far. But the following winter was especially frigid, and both vines died. While the regular seeded concord is extremely hardy and grows well in northern climes, hybridization to eliminate the seeds and retain the flavor has resulted in a much less hardy variety.

The most readily available tool to determine hardiness is the U.S. Department of Agriculture’s Plant Hardiness Zone Map. You’ll see versions of the map in gardening books, magazines, gardening technical publications, as well as online. The maps indicates the average low winter temperature in each zone. It has become the standard by which gardeners and growers can determine which plants are most likely to thrive in a locale. Note that little disclaimer “most likely.” The map shows zones based on the average annual lowest winter temperature, which means there are lower and higher temps in that zone. Each zone indicates a 10-degree Fahrenheit difference from zones one number higher or lower.

Some versions of the map use a system with “a” or “b” number suffixes. This improves precision by moving the scale from 10-degree increments to five. In case you’re curious, Tooele Valley falls somewhere in the 6a to 7a zones. The 6a zone has a low average of -10 to -5 degrees F, 6b averages a low of -5 to 0 degrees , and 7a comes in at 0 to 5 degrees.

There is a similar-looking map that many of us are familiar with. It is commonly found on the back of seed packets, showing the estimated time to plant the seeds in the package. Although it may look like the hardiness map, it isn’t. The seed package chart is more related to when soil and average air temps are suitable for planting, and usually come with the disclaimer, “Plant two weeks after all danger of frost has passed.” So, the seed packet map guides us as to when to plant, because it focuses on when warming occurs, not average coldest temps in the winter.

The USDA hardiness map helps us to zero in on what to plant. Because perennial plants and shrubs over-winter out in the landscape, understanding what will withstand various levels of cold will greatly inform your purchasing decisions and protect your landscape investments. I generally look for plants that will survive well below zero. Some may do OK into the teen temps, but it’s risky.

Plants that will survive only to about freezing but are desirable plantings are candidates for pots that must be moved in when winter approaches and put outside as the weather warms. It’s more labor intensive, but this allows for more variety. We have a blue potato bush that is over-wintering in our home, since it’s hardy only down to 20 ∞F! It will put on a gorgeous display of blooms in the warmth of summer and early fall, so we think it’s worth the effort.

You also need to consider soil pH. Our soil and groundwater is fairly alkaline, as evidenced by scale deposits on plumbing fixtures, windows and evaporative coolers. So, acid-loving plants, such as blueberries and azaleas, may survive here, but they won’t thrive — at least without an incredible amount of effort on your part. Hydrangeas can grow here, but will tend to bloom pink. Acid soil or fertilizer is needed to produce blue blooms. Also, our soil usually contains clay, which can crust, inhibiting proper seed germination and oxygen penetration. Adding lots of organic material over time will really help.

Make sure to take into account our elevation and the natural habitat that the plant usually grows in. Early on, I planted my share of quaking aspens, and some of them have survived. None have thrived, and they look really bad in the heat of summer. Why? They are mountain trees. So they don’t do well here on the valley bottom, and especially as single- or small-batch planting. “Quakie” stands in the mountains are living communities with hundreds of trees and saplings.

Avoid problems by checking out tree or shrub suitability before you plant. One way to do this is by visiting and accessing its tree browser. This great tool has plenty of pictures and selection tools to help assure you choose a great planting that will do what you want it to and live for many years. Or you can check out landscapes around you and see what appealing specimens are flourishing and have gone through multiple seasons.

Don’t forget water requirements! Poplars, willows and cottonwoods tend to be riverbank (riparian) species that require high amounts of water. Other species don’t like much water, or won’t tolerate “wet feet” where there is standing water. Many landscape plantings will require higher amounts of water over the first couple of seasons until they get established. Be sure to take this all into account.

While there are more considerations, these will greatly boost the probability of your choices being great. And there is no substitution for keeping a journal of what worked well and what hasn’t from year-to-year. A few moments of mapping, diagramming or jotting down varieties and planting methods, will give you a great start in the seasons to come.

If you’d like to explore this topic further, I’ll be presenting at the upcoming Master Gardener Spring Expo this Saturday, Feb. 24. Entitled, “Variety is the Spice of Life,” we’ll hit on more ways to know what will do well before you commit dollars to it. The Expo begins at 10 a.m. at the USU Extension Offices, 151 N. Main, Tooele, with registration beginning at 9:30 a.m. The cost to register is $5. If you’ve heard enough from me, there are seven other great presentations as well. I hope to see you there.

Jay Cooper can be contacted at, or you can visit his channel at for videos on the hands-on life of gardening, shop and home skills, culinary arts and landscaping.

Jay Cooper

Garden Spot Columnist at Tooele Transcript Bulletin
Jay Cooper is a new contributing writer for the Garden Spot column. He replaced Diane Sagers, who retired in November 2013 after writing the column for 27 years. Also known as Dirt Farmer Jay, Cooper and his wife have been residents of Erda since 2001 after moving to Utah from Tucson, AZ. A passionate gardener and avid reader of horticultural topics, for several years he has been a member of Utah State University’s Master Gardeners Program, and served as chapter president in 2013. Cooper says Tooele County has an active and vibrant gardening community, and the Garden Spot column will continue to share a wide range of gardening, landscaping, home skills and rural living themes.

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