Delaying Orchard Blossoms

It is February 29th and the fruit tree buds are swelling so much that I can see petal tips. To help ensure a healthy fruit crop, I’d like to delay blossoming as long as possible. Here in the high desert, the average last frost is April 17. Does anyone have tips for delaying blossoms on mature fruit trees?

As an experiment, I am painting the apricot, peach and almond tree trunks and lower branches with a 1:1 mix of white flat outdoor latex paint (no antimicrobial additives) and water. This means the white paint will cover the trees to a height of six feet as opposed to my usual two feet of trunk only. Has anyone else tried a more extensive use of white paint such as this to reflect the heat and delay early blossoming?

Same here. My peach tree already has 1 inch green tips and flower buds are swelling. I am going to see first bloom in a few days, almost 3-4 weeks earlier than usual and out last frost day is in late April.

I add more mulch under the tree and threw layers of cardboards on top to cool the soil down. But I guess that's too late. I also have some craft paper bags ready, in case there's a killing freeze coming, I am going to double bag and save some fruiting branches.

We got down to 21F the night before and there was a 10-hour period of below freezing temperature last night and the green tips seem unharmed. Maybe the tree is more resilient than I thought. Good luck with your fruit trees too.

because of late frosts after blossom and even fruit set dropping off I'm ready to cut down all my 12 year old peach and cherry trees. ive only had cherries one year and have never gotten not peach from the dozen or so trees I have. if they dont produce this year then next winter they are all getting cut down, roots pulled and the area plowed for a new garden spot. if anyone wants to come get clippings off any of these large high quality organic fruit trees from East Tennessee come and get them for grafting or rooting. they are great trees but they just will not produce fruit when frost and freeze hits the blossoms or early fruit set.

Hi Bruce, if the peach trees you have are not suitable for the local weather, what other variety can you get instead? I am wondering with the wilder fluctuations in temperature changes, fruit trees requiring longer chill hours would have more advantages? That way they will come out of dormancy later to avoid the cold damage.

GA peach crop dropped 90% last year, hopefully they will have a better crop this time. I come to propagate more figs that bear fruits on one year wood since the harvest will be more guaranteed (lost 25% due to early frost but still better than 100% loss in peach).

Bruce writes,

because of late frosts after blossom and even fruit set dropping off I'm ready to cut down all my 12 year old peach and cherry trees

May writes,

if the peach trees you have are not suitable for the local weather, what other variety can you get instead?

Maybe instead of chopping down the trees that aren’t working, Bruce could graft other varieties of peach scions and cherry scions on the mature and healthy trees. Since cherries and peaches are both stone fruits, grafting onto the existing trees during late dormancy might provide opportunities to experiment with many peach and cherry varieties with varying chill hours as May suggested. Perhaps it is possible to get a large sample of cuttings from an agricultural extension office near your home.

One of the things I recall my grandad mentioning that I didn't pay close enough attention to when younger was that he pushed boundaries for some fruit trees in central Idaho by spraying with water in freezing winter weather. Built up enough ice to keep the tree dormant while the early warmth worked at melting that ice before it could bring the tree out of dormancy too early ,like it usually did for those fruits in that region, with the results described in the OP.

Don't remember if he said he encased the tree itself in ice, or if he built up a ring or cone around it on the ground. No recall of what volume of ice he used, but that should be fairly easy to calculate with all the data we have on typical weather patterns now.

I tried with one expendable tree last winter. A ring of ice on the ground seemed the more plausible method to my best guess. All I succeeded in doing was sealing the roots off from the air, I think. Probably I suffocated it. For whatever reason, it never woke up in the spring.

Next try will be spraying ice spokes out from a tree trunk, so that the root zone can still breathe. Will also be creating different volumes of winter ice where there are no trees to slaughter, and observing how long into a typical spring here they'll hold the soil in dormancy temps.

Thank you for your remembrances of your grandad's efforts C. You may enjoy the following article from Rutgers which confirms and elaborates on the use of sprinklers to protect blossoms from damaging freezes:
Active Frost Protection Methods for Your Orchard
I find the title of the bulletin helpful in distinguishing two approaches: active and passive. The additional mulch suggested by May (keeps soil thawed so moisture can penetrate) and the white paint approach (prevents dark branches from absorbing heat), are both, in my opinion, passive approaches. They attempt to prevent the early blossoming from happening in the first place by taking preventative measures. I find passive approaches allow me to observe, anticipate, and build resilience to potential problems and address them before they happen.
If we could just fortify the context (or the field) with many small steps, we may be able to delay blossoming. What permaculture approaches could we implement now to reduce the effect of temperature extremes that threaten our fruit crops?

Ho Amy, how are your trees doing? I have the first peach bloom today, typically it should be in late March or early April. And I also have a 99% killin blossom due to the record low temperature in January. I am suspecting seed grown tree is from a Georgia or California orchard and not that cold hardy. I will try grafting too.

Here’s the update as of March 11:

The apricots have bloomed a week earlier than last year here and throughout the neighborhood. I see the peach trees are flowering today. The owner of the vineyard across the street is worried that he’ll lose this year’s crop due to early flowering (the buds are swollen now).
Instead of crossing my fingers and hoping the late freeze won’t come, my big effort for the last few weeks has been painting tree trunks white to keep the peach, almond, plum, cherry, apple, and pear trees as cool as possible to prevent early blossoming. I noticed while painting that I’m covering up quite a lot of sun scald from last year: I probably should have painted the trees last fall after the record breaking heat. Today, I will continue painting the grape arbor, pavers, fence posts and other hardscape features white in an attempt to prevent the landscape from absorbing heat, possibly slowing the fruit maturation process (the bigger the fruits get, the more losses in a freeze). The neighbors are asking about my “ghost trees” and the rational for the white paint so hopefully things will work out and we will all benefit from this experiment.
I tried a couple of cleft grafts on sour cherry stock using Stella sweet cherry scions that are dormant. I’d like to try grafting other late sweet cherries such as Black Gold. I’ll probably have to buy a tree to get the higher chill hour scions to use for grafting. I bought one high chill hour bare-root apricot and, happily, it is still dormant. I hope to use scions from that tree to graft onto the early blooming trees.
The other approach I am using, as May suggested, is heavy mulching. The main resource that I have for mulching is horse manure (abundant here) mixed 1:1 with wood chips outside the drip-line of the trees; all composted material is already on the drip line.
Doing all I can to keep the soil and tree temperatures cool and stable is the main strategy I am taking to adapt to the erratic weather.

If the question is, what can one do to delay blossoming, the answer is, not a lot.

I found one reference to the University of Texas successfully using evaporative cooling to delay blossom development and emergence.

Just about everything else about temperature moderation in orchards and nurseries is about preventing cold damage after emergence.

David the Good has several YT videos on how to graft. He's quite entertaining and it's useful information.



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Amy Gardener wrote:Bruce writes,

because of late frosts after blossom and even fruit set dropping off I'm ready to cut down all my 12 year old peach and cherry trees

May writes,

if the peach trees you have are not suitable for the local weather, what other variety can you get instead?

Maybe instead of chopping down the trees that aren’t working, Bruce could graft other varieties of peach scions and cherry scions on the mature and healthy trees. Since cherries and peaches are both stone fruits, grafting onto the existing trees during late dormancy might provide opportunities to experiment with many peach and cherry varieties with varying chill hours as May suggested. Perhaps it is possible to get a large sample of cuttings from an agricultural extension office near your home.