Most trees and plants grow poorly at high altitudes because of the cooler surroundings and adverse growing conditions. Even growers in California’s High Sierra region experience shorter growing seasons and higher winds than those at lower elevations and also the same latitude. Nut trees along with other seed-producing plants frequently fare particularly poorly at high altitudes. If you live at high altitude, you also can get far better results by protecting these plants in the worst environmental influences and choosing types that deal better with higher humidity conditions.
Definition
The definition of “high altitude” fluctuates depending on who you ask. Meanwhile, the University of Wyoming considers gardens located above 6,000 feet and over to be located at high altitude, while the University of Idaho defines high altitude as 4,500 feet or even more. Growers from the Sierra Nevada foothills may deal with elevations just as large as 3,000 feet above sea level. Your garden’s real altitude can greatly impact the types of nut trees that are acceptable for your location.
Altitude Tolerance
The nut trees you pick for your high altitude garden ought to be able to withstand the lower winter temperatures related to higher altitudes. Ideally, you should pick varieties that are hardy to at least United States Department of Agriculture Zone 4. Of typically cultivated nut species, just butternuts (Juglans cinerea) and black walnuts (Juglans nigra) will survive in cooler high-altitude regions. If you live at high elevations within an otherwise warm climate, then you could also be able to grow almonds (Prunus dulcis), Persian walnuts (Juglans regia) and hazelnuts (Corylus spp.) . The single-leaf pinyon pine (Pinus monophylla) is also a good selection, as it produces rich pine nuts and could survive at elevations around 7,500 feet above sea level.
Chilling Hours
When you choose a nut tree for your high altitude garden, you must take more than just its hardiness into account. Many species also have specific chilling requirements. If they don’t receive the right number of cold exposure, then they may not flower or fruit properly. Look for trees that have frightening demands of 1,500 hours or more so you will not lose blossoms to a late frost. This is particularly important if your area has a short growing season.
Pollination Requirements
Most nuts require pollination by insects or wind, which is unreliable at high altitudes. To ensure your hardy nut trees become fertilized and keep a good harvest, start looking for self-pollinating varieties. According to Purdue University, these comprise the hazelnut cultivar “Winkler,” the Persian walnut cultivars “Hansen” along with “Colby,” along with various types of butternut. You can also pick native species that may have nearby wild pollinators, such as pines and black walnuts.
Growing Strategies
High altitude gardeners could have success planting nut trees that aren’t normally suitable for their climates by using the right cultural techniques. These methods involve creating a special microclimate that is more conducive to healthy tree growth. Should you put your trees in full sunlight, you can decrease the amount of needed frightening hours. By planting near a stone formation, wall or grove of evergreens, you can protect young plants in the end and improve their odds of surviving the winter.