The Front Range is expecting a winter storm with temperatures expected to reach the low 20’s Fahrenheit, 3 to 5 below 0 Celsius. This event will likely cause significant bud and blossom death in fruit trees in this area, as well as to other fruits and vegetables. How much damage is determine by the specific plant (apple, peach, grape, spinach, etc) and the development stage. There are methods to limit or prevent damage, and we recommend you do some research and apply as appropriate/reasonable to your specific plants, location and resources. Mark Longstroth with Michigan State University Extension has a couple of tables with critical temperatures for tree fruits, which you can find here: http://msue.anr.msu.edu/news/freeze_damage_depends_on_tree_fruit_stage_of_development
This weather event is not expected to out right kill any apple trees on the Front Range, but local conditions and the health of individual trees vary, so it is possible. We will keep an eye on our trees around Boulder County and certainly take note of this event.
A large majority of the pink flowered trees you see in and around Boulder County over the past couple of weeks are apple and crabapple trees, and a large portion of the white flowered trees are as well (some are pear or other type of fruit trees, and some are non-fruit bearing trees). All of the crabapples species are in the Malus genus of the Rosaceae famliy.
The apples you see at farmer’s markets, road side stands, grocery stores and everywhere else are all, with exceedingly rare exceptions, descendants of a single species of crabapple, Malus sieversii. M. sieversii is also known as Asian wild crabapple or Almaty crabapple. Almaty is the largest city of the country of Kazakhstan, in central Asia near China. The mountains and hills near Almaty have forests of wild apple trees, just as the mountains and hills of Boulder County have forests of Ponderosa, Spruce and Lodgepole pines. Imagine our hills and mountains to the west covered with apple trees….
Those wild apple tree forests are being cut down at a rapid pace to clear the land for farms, buildings, roads, and other human infrastructure. The planet is in the process of losing it’s apple genetic diversity, which is a threat to cultivated apples everywhere. But, there is something you can do. The USDA has a collection of wild central Asian M. sieversii at their research station near Lake Geneva, NY. Scientists with the USDA have conducted genetic studies of these trees, and have determined that a ‘core collection’ of about 100 trees covers about 95% of the genetic diversity represented in the entire collection. Widespread Malus has been requesting, from the USDA, seeds and scion material from these core collection trees for three years, and working with others around the country (and globe) to share and distribute this core collection of apple genetic wealth. If you would like to participate, please get in touch with us, see our contact page, and let us know. You do not need to know anything about apples trees, or need much space to grow a tree. We can help you with choosing an appropriate tree for your space and level of interest. We only ask that we have access to the tree in the future to gather scion material and some of the fruit (and the seeds) if we need it. We are out of trees to plant for 2016, but please sign up for planting in the spring of 2017. Letting us know now helps us prepare trees for next year.