Fruit tree questions! - Ask Extension
Hello! Were about to buy a house in aurora co. I've found that the zone is 5a. Were looking to plant semi dwarf multi grafted fruit trees next year ...
Knowledgebase
Fruit tree questions! #174717
Asked April 13, 2014, 3:16 AM EDT
Hello! Were about to buy a house in aurora co. I've found that the zone is 5a. Were looking to plant semi dwarf multi grafted fruit trees next year (peach, plout, cherry and pear) and was told by the site I was looking on (groworganic.com) that I need to know the "chill hours" range for my area to choose the best types of fruit. what are chill hours? and how many to we generally get? will they affect fruiting shrubs, blue/rasp/blackberry? also, do elderberries grow well here?
Thank you!
Thank you!
Denver County Colorado
Expert Response
"Chilling hours" are the number of hours when temperatures are 32-45 degrees F. between tree leaf fall in Oct to leafing out in spring/April.
Generally the Denver area has about 1650 chilling hours. A fruit tree like an apricot with only 500 chilling hours needed will "decide it is safe to bloom" way too early here, subjecting its blooms to kill by late frosts.
Most apricots have chilling hour requirements of 750 or less...so they are not very dependable to fruit here because they bloom so early. If you want to try, Goldcot, Mormon and Chinese bloom a bit later but are still not dependable for fruit.
It will be better to plant peach varieties with longer chilling requirements of 900-1000 hours(Redhaven, Intrepid, Contender, Surecrop and many others) than ones meant for Georgia with only 500 chilling hours needed.
Peaches and apricots should be planted on a N or E exposure rather than a hot S or W exposure.
Sour/tart cherries (Northstar, Meteor, Montmorency) are more dependable than sweet cherries here.
Pluots being hybrids of Japanese plums and apricots are less dependable for fruit here. European plums (prunes) are much more dependable but will be prone to aphids.
Pears are mostly dependable BUT you'll need to plant only fireblight-resistant varieties, as fireblight, a bacterial disease of pears/apples, is very prevalent here.
Blueberries are difficult - but not impossible to grow here due to their requirement for acidic soils (our soils mostly alkaline). Red raspberries in particular grow well here. Blackberries can do well in the Denver area. Elderberries generally do well, though some varieties may be better adapted than others.
Generally the Denver area has about 1650 chilling hours. A fruit tree like an apricot with only 500 chilling hours needed will "decide it is safe to bloom" way too early here, subjecting its blooms to kill by late frosts.
Most apricots have chilling hour requirements of 750 or less...so they are not very dependable to fruit here because they bloom so early. If you want to try, Goldcot, Mormon and Chinese bloom a bit later but are still not dependable for fruit.
It will be better to plant peach varieties with longer chilling requirements of 900-1000 hours(Redhaven, Intrepid, Contender, Surecrop and many others) than ones meant for Georgia with only 500 chilling hours needed.
Peaches and apricots should be planted on a N or E exposure rather than a hot S or W exposure.
Sour/tart cherries (Northstar, Meteor, Montmorency) are more dependable than sweet cherries here.
Pluots being hybrids of Japanese plums and apricots are less dependable for fruit here. European plums (prunes) are much more dependable but will be prone to aphids.
Pears are mostly dependable BUT you'll need to plant only fireblight-resistant varieties, as fireblight, a bacterial disease of pears/apples, is very prevalent here.
Blueberries are difficult - but not impossible to grow here due to their requirement for acidic soils (our soils mostly alkaline). Red raspberries in particular grow well here. Blackberries can do well in the Denver area. Elderberries generally do well, though some varieties may be better adapted than others.
