Everything was growing exceptionally well until about two weeks ago and then all my apple and pear trees stopped. It is almost like stepping into a fire ant bed and not knowing it. About a thousand of them will quietly crawl up your leg and all at once they send out a silent signal to bite. They are getting adequate water and fertilizer. What is going on?
If you have had a bought of very high heat that is likely the culprit. Trees tend to take a nap in my area when the temps start reaching daily highs in the 90s.
Most of mine stopped growing more than a month ago.
Apples and pears tend to be determinate growers, unlike peaches and J. plums that keep growing vigorously the entire summer. Here terminal buds can set anywhere from mid July to mid Aug, which is prime summer pruning time because of reduced regrowth (although limited spring pruning can help counter biennial bearing better, IMO). If you only prune espaliers once during the growing season it is also when that is done.
As far as heat, if the trees get sun early in the day they can photosynthesize then but may be storing the energy instead of investing it in new wood. I believe the stomata close up when temps reach the 90’s and apples and pears grow best in the high 70’s. All species have their specific ideal temps- both soil and air, for most rapid growth. .
Interesting observations on how heat can stop a plants growth. IMO, if a plant has everything that’s needed during high temperatures, it will not skip a beat.
I know a guy with an apple orchard in Oregon, wet winter drier summer. He doesn’t start watering until the apples set terminal buds. Mine quit growing in early summer and that’s it for the yr. That’s what I want. Apple fruit are normal to large size and high quality.
I believe there is a point that even in moist soil it becomes too hard for leaves to remain adequately turgid because of high heat with stomata open. Relative humidity plays a role and in a green house plants continue growing at higher heat because of the constant high humidity. I don’t think it is a matter of opinion, but I’m speaking from memory of botany classes taken 25 years ago. If you are curious search it up.
PG, temperature is one of the limiting factors in plant growth. There are upper and lower ranges in which each type of plant can perform different biological functions, as well as optimal ranges for each plant. All other needs can be met, and a plant will still not grow if the air or soil temperatures are out of their range, especially if it is for extended periods. Night temperatures also play a role. The lower ranges are very obvious, but not all areas exceed the upper ranges for what they are growing. So, it would be easy for an individual to not observe the effect.
Perhaps one easy to understand example would be lettuces. They would not sprout if I planted them outside this time of year. Even if I were to sprout them indoors and transplant lettuces to the ground, they would not only fail to grow, but would die in our summer which is mostly in the upper 90’s and low 100 degree range for several months. Of course, it wouldn’t take months to outright kill the lettuce. That was simply an example to show that temperature is one of the parameters in both plant growth and survival.
I won’t be so sure about that Alan. Crops vary but many grow well in areas like Phoenix and the inland deserts of southern CA where night time lows can be 90F. Crops like pecan, citrus, pomegranate, grapes, and similar do very well in that area if given enough water. Stone fruits and apples do well in cooler areas like Bakersfield and Fresno where average highs are still 100F. They even grow sweet cherries around Bakersfield. True those can coast during high heat after harvest. But pecans need to maintain high photosynthesis all summer to achieve high yields of oil rich nuts.
I’m not talking about surviving but actual growth of trees, especially ones that evolved in relatively cool areas. But I’m not so sure about the specifics either because my memory may be combining or confusing different information, including optimal soil temps for apple tree growth as opposed to air temp.
I just did my own search for info about how high day heat may effect photosynthesis of apple trees but came up empty. Apple trees grown in hot areas may just do more of their energy harvesting early in the day before it gets too hot and overall harvest more energy before and even after the dog days of summer.
At any rate, what I said about apples being highly determinate in their growth habit is true and well known although it seems to be more the case some years than others. Last year there was a lot more late growth than usual.
As for one who has tried a lot of different methods for getting the most out of a plant, it’s definitely not just one fertilizer that will do everything. Here in CA, the temps will rise once again past the 100’s. The apple tree will not be taking a nap.
If that photo was just taken, your apple tree looks completely baffled. It hasn’t a clue of what is the season. I guess it will be ripening fruit in Feb.
Our high temps recently have been from 90-100 and the lows have been 75-85. I wasn’t watching closely last year but I’m pretty sure it happen then as well. Seems like I got some later that season growth in 2015.
This will be the second harvest this year Alan, what’s there to be baffled about?
It’s probably a low chill apple like Anna or Golden Dorsett based on Ron’s location. I believe that Anna is especially prone to blooming 2 or 3 times per year in extended growing season areas.
That doesn’t make the area better for growing apples, though. In NY you can grow a much larger variety of what, IMO, are better tasting apples because the temperatures there more conducive for a greater range. One of these years I’m going to harvest apples that I personally like here. So far, the ones I’ve harvested have been better enjoyed by others, but not my preference.
Yes that’s a Golden Dorsett and my choices are limited due to very low chill hours.
Well, your situation is not universal. Even where I was raised in S. CA (Topanga Canyon) the apple trees I played with only provided one crop a season- back then very few people grew apples at all there and these two Beverly Hills apple trees were at the base of the canyon towards the SFV side in a cold spot and went fully dormant in about mid-Jan.
In the tropics apple leaves are stripped to mimic dormancy. Does your tree ever achieve sleep?.
Alan, Golden Dorsett a and especially Anna are notorious for setting a second (and with Anna, even a 3rd very small) crop. I don’t have any other apple cultivars on my property that do that, although Kevin could probably tell us if there are other very low chill cultivars that do this. Often, if I have a really mild winter, the Anna leaves don’t drop until new leaves in the spring push out the old leaves. But, long periods of very high heat will make many plants stop growing. Tomatoes are a good example. Citrus as well. But, as fruitnut points out, other plants seem less affected - my pomegranates and figs continue growing and maturing their fruits through to fall. Mangos and Papayas love it hot, hot, hot. Just need to provide enough water. I’m waiting for Eric A. to weigh in about long periods of very high temps and growth rates. Eric is probably our resident expect on that. And Kevin as well, as it can get PDH (pretty dang hot) in Riverside, CA as well.
And Ron, you’re not as limited as you might think with apple trees. I grow a whole lot of different apple cultivars, many that are higher chill. If you go to Kuffle Creek’s web site, Kevin talks extensively about the ability to grow just about any apple cultivar here in S. California. My zone is probably very similar if not the same as you (N. San Diego county coastal hills, about 6 miles from the ocean). It’s pretty fun, I have to say. Going to have a bumper crop of fall apples this year, very excited.
Here in Phoenix we observe a slow down in growth that we commonly call “summer dormancy”. Personally I dont believe that the term really fits, it more of a summer slow down not a absolute stop. Apples tend to be the worst effected, peaches and plums the least.
It at its worst starting the second week of June and starts to ease when our monsoonal pattern brings humidity and slightly less heat to us in mid to late July. How much the tree is effected is strongly dependent on the vigor of the rootstock. Cherries for instance will burn up in this summer dormancy period if not on a rootstock that his the vigor to push the tree to keep producing new wood and leaves despite the heat. In general the more dwarfing, the more summer dormancy prone.
A strange little factoid is that our Anna’s and Dorsett’s also re-bloom several times after June harvest but completely fail to set unlike what happens in SoCal. Im guessing that its a pollen sterility issue due to high heat? Same thing happens with any tropical that tries to flower during the high heat of summer (starfruit in particular). Might be a high heat/low humidity combination because the situation eases once the monsoon moisture kicks in near August. Sometimes we will see a few apples set then in late august/early September but there isnt enough season left to size them up and ripen them.