Rain during bloom

I fully get that nature has always found a way and over the countless centuries has “perfected itself”. Now that being said we all know nature isn’t perfect. Plants bloom only to have freezes wipe them out. Plants grow in areas only to have colder temps kill them. So nature is far from perfect so this is the reason I ask this question. Does rain during bloom cause any issue with pollination, fruit growth, etc? With my potted stock would it be better to bring them in during times of rain, or is it safe to leave them outside? I fully get that in-ground plants deal with this all the time but they also grow much bigger, have many more flowers, etc that losing some might be part of a natural thinning.

So does anyone have any thoughts, or research that suggests what to do?


Rain during bloom can cause disease issues. We don’t have it here because we are dry in spring. But in CA I had a lot of losses one spring.

In terms of just pollination I don’t think rain will have a significant effect. Have read that long periods of cold but above freezing can cause the pollen tube to abort before it reaches the ovary.

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And if you are relying on honeybees for pollination, cold rainy weather can keep them from flying. I am not sure that moving them indoors would help on that account.

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Thank you for posting that Fruitnut. I have seen the same thing and wondered what was going on. One year the low temp for spring bloom was 29F (for one morning). Yet there was a very poor fruit set for peaches that year. I had assumed the published frost damaged charts were simply overly optimistic. But there were also extended periods of cool (though not freezing weather that spring during bloom). Your explanation makes good sense.

Sean: One way to put any plant into stress is un-natural environments (ie. smaller feeding area). Best explained is a state of plant confusion or “stressed”. Which you can google countless scholar studies about stress and the implications are they become more disease prone. Of course then the smaller the pot the shorter the average lifespan, unless your able to remove the threat of diseases by taking shelter for your pots from the wind and rain storms.

You find that stressed plants are more prone to insect damage and diseases. Too much of all the natural elements against them, the more confusion, the more unfocused to any single problem, the ultimate fate. Or (in your case) you make up lots of ground by changing the external variables (ie. moving around to shelter the storms they can’t weather).

The subject of pollination is huge too. Which has little resembling of subject of stress, other than as a different source point of infection from the flower and the drawing in of disease through it under conditions of dampness. Some smart plant can detect a problem in the flower too then abort/“wall it off”.

The huge mystery of the plants and the fight to survive and balance with other organisms… brings lots of adaptability.

Can you disclose what kind of fruit? For example a variety of apple grown on it’s own root outside might require being grafted to a more adaptable m-9 dwarfing rootstock in a pot. Still shorter lived but an example of what grafting is about to tried and proven situations of adapting.

Rooney, I’m guessing you are a west coast grower. In the east coast and the entire planet where it rains a lot during the growing season, all common fruit trees face issues that can wipe out the harvests and even foliage no matter how happily and healthily trees are growing.

All gardening is an unnatural activity in that humans are trying to stack the deck in our favor which is certainly not the intent of our dear Mom Nature.

On the subject of pollination, a few rainy cool days shouldn’t be a problem because the blooms stay on the trees longer during such weather (probably no coincidence there).

A single warm sunny day may be enough to accomplish the job if you have a good presence of pollinators. Sites I manage where pollination is sometimes a problem seem not to have an adequate population of our native “buzzem buddies”.

As far as above freezing being an issue, it is widely believed by growers around here that a cool wet spring leads to a poor fruit set. Most think the problem is the honey bees don’t leave the hives. I believe the tree aborts the fruit in these situations because of depleted energy supply. In this case, the problem may be as much about cloud cover as cool temps.

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I’m not just a west coaster with fruit but also interior Alaska. I look at what you said and wonder that it is not a programmed strategy of the tree to vary populations of animal life or predators. For example birch trees in interior Alaska and around my property have decided to produce massive amounts of female flowers the last 2 years in a row. In turn massive amounts of seeds accumulated in the snow, in turn feeding increasing populations of voles through the winter. Numerous owls (though the linked news article does not mention owls) now are the ones kind of putting a population check on the voles.

Ideal conditions create bounty of birch seeds in Interior Alaska | newsminer.com

There are always deep questions about fruiting events such as this as to why? (concert control over the animal kingdom?) (wipe out pests?)

I guess it would behoove a population of apples to not serve a fruit source to say codling moth in one year (or a couple in a row) so that following years with no codling moth some seed can survive.

Similar to the concept that the AIDS virus has become decreasingly lethal so the human host can feed it longer.

But coddling worms don’t always eat all the seeds of fruit they inhabit, do they? At any rate, even in worst infestations here they seem to miss some fruit.

I don’t know what your saying. I mean that birch have a great influence on the animal kingdom. With that exerted influence quantity of seed as a variable from year to year the voles can, in low population years, avoid eating all the spruce seeds. Or the other way around, it may be (in high population years) they are distracted away from eating all spruce seeds. Either way the voles are possibly tricked by birch seed. Then, in turn more spruce germinate and inhabit interior Alaska. Meaning that Spruce and Birch may be co-dependent to each other. These are unanswered questions, but on my property and everywhere else, I have never seen one and not the other.

Probably because I didn’t know what I was talking about.- my comparison was inappropriate to what you were saying. I get a bit fuzzy headed in spring (or is it in the afternoon?).

Here naturalists sometimes say that oak trees have variable cropping so that squirrels go through booms and busts in population and after a bust a heavy crop is not eaten and therefore can sprout.

I always found that idea suspect though, because the squirrels are said to never find all the acorns they bury (I’m one to say it because they sometimes hide acorns in my tree pots and they sprout). And those seeds get well dispersed.

I got you now.

So to bring that all back to the original idea it seems natural for any tree to cue together whether it be birch, oak… or what not, to starve out critters that compete against the future stake of tree wild stands. It must be agreed then that trees can’t communicate to each other and figure out when to go unproductive but they listen to the weather for the starting flag and then by June (or flowering time) they drop (or June drop). The original question made lots of sense, then pollination is one thing, and what a tree decides to do is another.

I believe stress also brings about such a change. I think usually fruit will be unproductive after an event or disease attack. I have heard more than once that an unproductive apricot can be convinced to put on a fruit show when hammered good at the base of the tree. (probably very early in the year)

It’s been cool and rainy during the bloom of my Santa Rosa Plum and Flavor Grenade Pluot. Now it’s looking like fruit set will be light. I was wondering if there was a mechanism at play beyond just pollinators not being very active, and came across this thread which I thought was timely. It’s an interesting thought that maybe the trees abort more fruits due to the cloudy weather as a result of lower energy generation. Any other thoughts/ideas?

It probably will be light. My fruit is never pollinated when it rains. Happened last year. Wettest summer in years, and no to little fruit.

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