It can be pretty cold from time to time. The Rockies mostly shield us from the really cold stuff that the upper midwest sees. Week long stretches of -20 weather was not all that uncommon in the 80’s and 90’s. I haven’t seen a winter like that in 20 or so years now. Mostly, the winters are just long and grey.
I would like to understand about pruning during the winter also. I am Zone 7 in Virginia and often prune late spring and don’t finish. Not sure I see the difference pruning February 1 vs March 1? We are susceptible to below freezing temps through the middle of April.
Not sure there is any. Pruning during dormancy is said to be good for making structural changes, pruning during summer will cut into the tree’s ability to store food for the coming season, and so is more dwarfing than dormant pruning.
As the tree wakes up and the sap begins to flow some trees will drip like crazy; No-way maples around here leave stains on the sidewalks if they’re pruned and the tree doesn’t have time to seal up before spring. Some trees may be more vulnerable to infection if they’re pruned at the wrong time. I’m scared to prune prunes/plums because I’m never sure when it’s safe!
Last year I pruned my peach tree in February. It was a young tree and I took out two water sprouts which was about 25% of the tree. It never came back from winter. Not sure if the pruning killed it or ambrosia beetle killed it or something else entirely killed it. But I’m not going to find out ever again and will always wait till at least March to prune.
I prune throughout the winter, there is a lot of pruning to do in my orchard and I like to spread the work out. This is in Zone 7a. Peaches and grapes I do toward the end as they are less hardy. Also I never prune before a cold snap, stop pruning a few days before one is to come.
This reminds me, I need to get going on it … it is more pleasant pruning now than in 20’s weather in Feb - !
When pruning established apples a cold snap to worry about for most varieties is around -25 F. I prune all winter long, all day long in Z6, often in snow, but not in cold rain (for my sake- not the trees). I’m really not sure about relative hardiness of pears and E. plums but pears do seem fine to treat like apples and E.plums may be hardier than J’s for winter pruning.
In 25 years the only species I’ve really been punished for pruning before a severe cold snap was peach trees- when trees were not at maximum hardiness and it was a late snap. but only in the single +digits. One time, one site and I’m sure I’ve gotten away with such temps on many other occasions.
The fact is the variability of hardiness for individual trees during dormancy makes clear guidance impossible. I’m also not sure at what age trees toughen up, but assume that once they are bearing full crops the main change has taken place.
I’ve read that wounds become less vulnerable to cold damage even during dormancy, and that it takes maybe 2 weeks to harden wounds, but I haven’t seen research. Some commercial growers in the Hudson Valley down to z5 do their main pruning in fall after harvest so their picking crews can do it.
I did some pruning to my peach tree today. The tree just got done dropping its leaves. Hope i dont have trouble with cold injury. I’m in 7b/8a Alabama. Nothing below 32 in the 10 day forecast. Seems unlikely we’d get cold enough here to have a problem. The coldest its been since 2012 here is 9F. Aother time it got to 12F. Some years it never got below 20.
I do my pruning starting in late Jan/early Feb depending on cold weather outlook. I start with apples then pears then blueberries (although recently snowpack in March has thrown a monkey wrench at this) then finally peaches in April (again with an eye on cold weather forecast).
I went ahead and pruned 3 of my peach trees yesterday, 2 of them larger trees. We are looking at highs from the 60’s to lows in the upper 20’s over the next ten days. One of the tree I had to use loppers on to make major cuts, so we will see how this all works in the spring.
Apparently the danger isn’t exclusively to the wood near the cuts but also to the affect on the over winter toughness of flower buds, which suggests to me that after summer the next time to prune peaches is very late winter at the earliest- unless you never have a problem with late frosts killing peach flowers.
The other aspect of it is that if you hold off pruning until the flowers start to open you have a better idea how vital they are and where in the tree. Sometimes the fattest flower buds on the best growth are the first to be killed.
Alan, i was under the impression that you pruned all winter long and even with peaches damage was uncommon, and when damage ocurred it was due to below zero cold. But i may not be reading carefully enough. If i have late freeze i can always cover my tree and put a catalytic heater underneath, but would rather not have to. It was fun pruning now anyway. I was bored due to a lull in the garden and orchard.
I’m talking about serious damage to wood when I say that. Flower buds are more complicated, especially with peaches, but I’ve apparently killed peach trees when temps reached single digits immediately following pruning, although only once. Probably because temps preceding were mild.
I’ve just noticed that with late frosts the fattest flower buds on the best shoots are often killed and the hangers that you would prune if you could tend to be more likely to survive. I prune my own peaches and nects when they are in bloom, but I can’t do that for all of my customers. Fortunately most them don’t have their orchards in a hollow.
Scott is quite right… especially pruning stone fruit before a very cold snap is a bad idea. The cold can kill the tree, or at least cause a lot of damage. Apples are much tougher and rarely are injured by winter pruning. Commercial orchards like mine prune apples starting in November or December though the winter, and don’t start on stone fruit until the threat of <15 weather is gone… March or so.
We also sometimes summer prune cherry trees (after harvest) because there is less risk of canker spreading when it is hot and dry… and it gives the trees a chance to grow buds on low growing branches that otherwise might get shaded out. … Same goes for peaches. Peaches (before harvest) have the additional benefit of reducing shading and increasing color on fruit. You’ll still need a second prune in spring, but there is less to do.