Will figs grow in Delaware?
USDA Hardiness Zone changes
Last week, the revised USDA Hardiness Zone Map was released. The revision is the first change since 1990. Most locations were moved one-half of a zone higher. The USDA attribute the changes to these criteria:
- They used data measured at weather stations over a 30 year period (1976–2005), while the 1990 map used data from a 13-year period (1974–1986).
- They used new measurement methods, including algorithms that considered changes in elevation, proximity to large bodies of water and extremes of terrain (peaks and valleys), which all affect temperature.
- They drew data from more weather stations than in 1990.
Some additional changes are zones 12 and 13 were added, and Puerto Rico is now included on the map. There is an interactive map that can be downloaded and printed. The new map is available at planthardiness.ars.usda.gov. You can simply type in your ZIP code to see your zone.
The zone map was created as a tool for gardeners and growers to determine which plants are likely to survive and thrive in any location. The map is used by magazines, catalogs, books and the nursery industry. The Plant Hardiness Map splits the United States into zones that represent the average annual lowest winter temperature in that location. Each zone spans 10 degrees farenheit and is further divided into five-degree “a” and “b” sections. For those of us in the Delaware and the Central Ohio areas, we are now considered 6a and not 5b — a difference of about 5 degrees.
So what does this mean to the average gardener? Not much. We still look at our gardens the same way as we did last year. The average gardener has always tried to grow plants labeled for higher zones, with some success.
The U.S. National Arboretum list of cold hardiness woody plants can be found at usna.usda.gov/hardzone/hrdzone4.html/#5.
Almost all of Ohio is Zone 6a, with a few exceptions around Lake Erie and small areas in Knox County and the Mansfield area.
The bottom line is some plants may be expected to have a better chance of surviving winter in our region than they did in the past. Jim Chatfield, a horticulture educator with the OSU Extension Center in Wooster, said the changes have moved the zones a bit and there is evidence plants can survive a little farther north than they did a few decades ago. When asked if they will carry new types of plants just because of the zone change, it appears that most nurseries will answer “no.”
It does mean, at least to me, we now have the support of a zone hardiness map to reinforce us to push the envelope a little bit more. Try to grow that Mimosa, fig or banana tree.
It’s for the birds …
Bird Source is a fun activity for this winter when things are dark and dreary outside. The Bird Source organization will again count birds from Feb. 17 through Feb. 20. All you need to do is visit birdsource.org, get registered and count away. The Great Backyard Bird Count is an annual four-day event that engages bird watchers of all ages in counting birds to create a real-time snapshot of where the birds are across the continent. It’s so easy to do and a great project for students, your kids or even you. Bird Source gets us out of the house and into the fresh air. It’s free, fun and easy and it helps the birds.
The project is led by the Cornell Lab of Ornithology and National Audubon Society, with Canadian partner Bird Studies Canada, and sponsorship from Wild Bird Unlimited. Visit birdsource.org and register today.
Susan Liechty is an OSU Extension Master Gardener volunteer.