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Notes on the Valley Landscape: Abundant harvest
Fruit production hard to predict
Kim Bock

Christmas gifting was easy for me this year thanks to the crazy amount of fruit we were blessed with in the Roaring Fork Valley. Even after sharing fresh fruit by the boxful, I spent several hours this fall stirring kettles of macerated plums, pears, peaches, apples and cherries. Friends received homemade jams and jellies out the wazoo, and I still have plenty for my family. 

This year was a very happy harvest compared to the dismal lack of fruit in 2017, when I was often asked if I knew of anyone with any fruit. The answer was essentially “no” for the entire valley. Why was 2018 so different? The main reason relates to the mild spring we had this year with no widespread destructive late freezes. Secondly, there is what I refer to as the rebound effect for fruit production. And lastly, we must acknowledge the spring weather and its positive (or negative) effect on our pollinators

How do freezes affect production? Fruit trees typically need a certain amount of cold temperatures (chilling hours) during the winter to allow buds to flourish in the spring. However, temperatures too low at the wrong time (even for a very short period) will kill buds, flowers or tiny fruits. Utah State University published an excellent picture chart showing bud and flower development combined with temperature minimums leading to fruit kill. For example, an apple tree in “first pink” flower will lose 90 percent of potential fruit if exposed to 24 degrees for only 30 minutes! Given this tightrope of weather and bud/flower formation, I am often amazed that we get any fruit at all! 

It is important to know the microclimate of where your fruit trees are/will be located and the chilling requirements of the myriad varieties from which to choose. The wide open “bowl” of El Jebel is usually colder than the in-town or hillside areas of Basalt. South-facing slopes (or areas on the south side of a structure) might experience several degrees of temperature difference than northern exposures.

If we are fortunate to have mild springs each year, should we expect great fruit production each year? Not necessarily. Heavy fruiting takes its toll on trees because of the amount of energy required. Following a season of heavy production, many fruit tree varieties “take a break” the next season and give a lesser amount of fruit even with favorable weather conditions. This alternating rhythm can be more pronounced with certain varieties of fruit trees. We love Honeycrisp apples, right? This modern variety is known to be a finicky biennial producer and requires special care for commercial growers. 

This leads me to say that “heritage” varieties of fruit trees can often be more successful for local home growers. The Roaring Fork Valley was settled by pioneers who brought hardy plants with them in the late 19th century. Many of these trees are still around — living connections to those challenging days. The Heritage Fruit Tree Project has been active in taking cuttings from these old trees and propagating them in conjunction with Colorado Rocky Mountain Permaculture Institute (CRMPI) on Basalt Mountain. 

An upcoming project at the Aspen Center for Environmental Studies’ Rock Bottom Ranch in Emma will establish a fruit tree orchard to help grow and preserve these heritage varieties. They will source their saplings from CRMPI, among other nurseries. Once in production, we can hopefully enjoy old-time flavors of fruit no longer available in our local chain stores. Consider donating to the Heritage Orchard Project by contacting cmahon@aspennature.org. If you haven’t been to Rock Bottom Ranch lately, I urge you to visit for their ranch tours. The talented staff provides engaging educational programs for kids, impressive seasonal vegetable crops, free-range produced meats and many fun community events. 

To wrap up the discussion on abundant fruit production, let’s remember our lovely pollinators. We think of European honey bees as our major pollinators, but locally we have dozens of native pollinators that fly under our radar, no pun intended. Many types of moths, wasps, flies and bumblebees are critical pollinators for our cultivated and native plants. Unfortunately, cold and wet spring weather can depress the maturation of these critters and reduce effective pollination at the correct time for the blossoms. 

Come spring and summertime, pause to observe these fascinating creatures working hard in your blossoms.  It’s a show which brings me great pleasure.


Kim Bock has studied landscape architecture, worked in city planning, and has been a practicing arborist for 20 years. Living in the El Jebel area since 1989, she has been an active member and officer in the Pardon My Garden Club and spent 19 years as a member and chair of the Roaring Fork Planning Commission. Besides flower and vegetable gardening at her home, she loves hiking with her dogs and husband.