I work for a small company in California that ships cuttings of a small tree, we call a tree collard. This plant is not easy to propagate from seed, so we send unrooted cuttings through the USPS all over the country. The question is, when can we send them so that they don't cook to death or freeze to death in mail trucks or mail boxes? We need approximate dates for the following: first hard frost, last hard frost, spring or summer for when temperatures are approaching 80 degrees Fahrenheit. I understand that Wyoming is a large state with many micro-climates, general averages are all we need. Thank you for your assistance, Roq
Mendocino County California
I would be doing you a disservice if I gave you a one-date-fits-all for the information you have requested. The state varies tremendously from one location to another in first and last frost dates, mostly due to elevation. It can freeze in Jackson, for example, in late July; in Powell the typical last date is the end of May. Good information can be found here: http://www.wrds.uwyo.edu/sco/climateatlas/temperature.html#31
First hard frost here in Laramie (7200 feet elevation) is usually the first week or two of September; last hard frost is usually the end of May. We don't plant annuals outdoors until the first week of June. Contrast that with lower elevations such as Sheridan, Torrington, and Powell: first frost usually mid-September and last frost mid-May.
Summers at higher elevations will reach 80F in mid-June and exceed 80s in July and early August. Lower elevations will hit 80s early June, often through the end of August.
Location, location, location!
Let me know if you need more information.