04/15/2023
I’ve been thinking about the national plant “hardiness zone” charts and over the years I’ve had people call me for planting advise. I have a few things to tell them that I’ve never wavered from and this year many of my predictions are coming true.
1. The hardiness zone is designed to let you know what will grow in your area and what will struggle because of the weather. Specifically, South Eastern Idaho is a zone 3 climate. Many zone 4 trees will survive but some years they may struggle but still survive. The large box stores buy their trees from sources that may be from a warmer climate. They ship them nationally to all stores with little attention paid to these zones. These stores are located in a large range of hardiness zones so although beautiful in the store, the tree or shrubs will survive at least through the summer but may not survive the winter.
For the past 15 or so years we’ve had zone 5 and sometimes zone 6 winters. Zone 5 or 6 trees may have grown to be large established trees. But as I preach on over and over, we still live in a zone 3 potential. That means maybe once every 10-15 years we will have a real Zone 3 winter. Maybe several in a row. This is one of those years and expect to see many established trees this spring fail to break bud or even die, even though they’re established they’re still not zoned for the area. Even some of the more hardy evergreens are not going to survive in Idaho Falls where they might be fine in Pocatello. I’ve seen many older pines that have severe winter burn, some have already passed the point of survival.
I’ve seen many other tree diseases crop up because the trees that are marginally compromised by the cold winter are weakened and susceptible to disease.
So when you are shopping for your new trees this year pay attention to the zone the trees will do well in. 3 and above Zones 2-3 and-4 is preferable.
Also pay attention to the soil type. Specifically PH. Our water in South East Idaho gets to us largely by passing through sand stone and limestone so our PH is usually around 7.5 or 8. This is ankaline and many hardwood trees will not survive unless supplemented with a fertilizer that includes sulfur. Common trees that require low PH soils are most trees that turn red in the Fall. Even Burning Bushes can benefit from a little acidic fertilizer. Choke cherries appear to be alkaline soil tolerant.
People ask, why do we see red trees in the mountains? Most trees in the mountains rely on rain water so the soil remains lower in PH. Even the amour Maple and Rocky Mountain red maples will struggle when brought here and watered with our well or runoff water.
Happy tree planting.
Kim Getsinger,
Wolverine Tree Farm
