Thoughts on Reducing Extreme Heat Damage and Sunburn for Fruits and Gardening

Last year (2020) was pretty extreme, with drought and heat. I had some sunburned apples and tomatoes, but mostly had good fruit production.

I’m not good at running outside in 100 F weather to cover my trees with tarps or whatever. Im trying to learn irrigation systems but my learning curve is steep, my well has a lot of sediment and Im waiting for a filter so the lines will stop clogging, among other issues.

This summer so far (It’s still only June) we had historic days with full sunshine and temps above 100 in the afternoons for several days. For two days, that was above 115.

My yard and garden sustained sunburn on fruits and leaves, many flowers and shrubs. And July, Aug are still ahead. Then there’s next year, and onward.

I know it could be a fluke but I doubt it. I am interested in future measures to reduce losses and damage in the garden in the event of more super hot and sunny weather events like what we just had.

That could include what varieties to grow, what cultivars, pruning practices, protective measures. For example, this week -

This year’s heat wave occurred after we harvested most of our sweet and tart cherries. So cherries are good this time.

Many of our apples are sunburned. I had been starting to prune them to have leaves above the apples. The most sun exposed apples seem to be the most affected, and the sun exposed side is completely sunburned. So pruning for a protective leaf cover above the fruit might help. Pruning for the greatest sun exposure - bowl shaped trees, for example - might be counter productive. I don’t know, these are my thoughts.

Same for pears, but the sunburn doesnt look as bad as the apples.

Persimmons look OK so far.

I harvested most of my raspberry crop before the heat wave. So as with cherries, earlier was protective.

I don’t know if Surround spray or Wilt-Pruf would be protective against sunburn. Maybe someone could chime in. White paper bagged fruit might have been wiser, but too late now.

So far my fig trees are not showing any damage. At least part of the blackberry crop is ruined. I might look for a crop cover of some type for them for next year. It’s too late for this year.

Our grapes look OK so far. Not sure about peaches, but the peach leaves are unscathed. Too bad peaches generally cant handle wet winters here. Plums look like a mixed bag. Hollywood seemed more vulnerable than greener plums so far.

Ornamentals are another matter. I have been moving towards succulents, which can be pretty nice yet quite tough. Many of our rhodies are like potato chip bushes now. Buddleia and Forsythia seem less vulnerable to sun.

Trees, too. I can’t imagine that it’s a good time to plant most evergreens. We had them removed around our house for fire abatement - Arborvitae and Junipers might as well be given cultivar names like “Roman Candle” and “Gasoline bomb”. Oakland learned that blue Eucalyptus is highly flammable, producing a miasma of volatile oils that burn explosively. So they might survive a hotter climate, but not be a good choice for a yard planting. I do have an Alpine Eucalyptus which is not supposed to do that.

Thoughts and experiences?

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I’ve successfully planted trees of all descriptions in zones 6 and 7 all 12 months of the year.

But, ideally, late fall and early spring are preferrable.

The big problem with extreme heat in PNW is the variability of temperatures. We get weeks of 60-75 and then BAM – a string of 95-115 degree temperatures. Trees dont develop the tough leaves or the deep roots that they would have to in hotter climes.
I’ve had terrible damage on my loquats – I was so looking forward to the fruit. And the crop was quite heavy too. Then in 3 days nearly 80% of the crop was burned to a crisp. The leaves are all heavily damaged too. I know these grow in Phoenix which is still much hotter than the PNW. Yet, they appear to have suffered more here.
Persimmons seem have mostly escaped the heat wave - there was significant fruit drop in my H118 american persimmon but the tree was heavily loaded to start with.
Apples and plums seem to have mostly escaped damage here but I had all the apples bagged for apple maggots. Maybe they were protected as a result.

Kiwis were hit very badly – My cordifolia was burned almost completely on one side. But fuzzy kiwis seem to be hardier against heat damage.
Pawpaws seem very tough – no heat damage to speak of. Feijoas also grew noticeably in the heat. Maybe persimmons, pawpaws and feijoa are future champs with the changing climate we are likely to see.

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@ramv, that is so interesting! Your pawpaws were tough as nails. Mine got sunburnt leaves. Not a lot, but enough to notice.

I imagine that well watered plants will be less likely to wilt. I don’t know if consistently well watered plants are more likely to have succulent, lush leaves that are more likely to fry. I think it’s possible. My young apple trees don’t show a pattern - some well watered and some not watered got fried, but also some well watered and some not watered came through unscathed. Fertilizing is also a consideration. I did give the baby apple trees a boost of nitrogen about three weeks prior. I also gave my sweetcorn a big boost of nitrogen just two days before the heat wave, and it had a big burst of growth, and no sunburn, but there’s a whole lot of difference between those species.

I had made a point of not watering my blackberries. My hope had been that by not watering them, the berries would have richer, more concentrated flavor. Instead, the ripening berries were completely fried.

I definitely want to bag apples next year with something that might reflect sunlight, like maybe white paper bags. I would have this year but there were too many other things happening and I have to pace myself.

A few years ago I thought about raising prickly pear cacti for the fruit. Maybe… :grinning:

My persimmons mostly look ok too, I didn’t look closely. Yates is about 20 feet downstream from the septic field, so may be getting some water that way. We don’t use anything toxic, but I imagine nitrogen compounds are there. Nikita’s Gift, which is on D. lotus rootstock, didn’t seem damaged. So you might be right about persimmons.

How did your figs do? Mine seemed to have a burst if growth and new main crop figs started. No growth tip damage, but I had just snapped off the tips in the last week or two. Brebas were not damaged. I usually don’t water my fig trees and didn’t before the heat wave, but they should have deep roots by now,

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Considering it has never been that hot in recorded history for the PNW,the chances are slim,we will experience something close to those temps,in the near future,hopefully.It’s was almost like the perfect storm for heat.
A number of plants in small to medium size pots have crispy leaves,even some that are native to places like Florida.Some fruit and leaves on a Xie Shan Mandarin were cooked.Small Loquats too.
I took a walk today,through downtown Redmond and a lot of shrubs had fried leaves,even parts of deciduous trees.

Feijoa and citrus are the only things for me that seem to have actually preferred the 115, demonstrated by growth. My young watermelon plants seem to have taken off in the days right after the crazy weather.

Plums seem surprising resilient to it, my Beauty, budded last year and began growing this spring, poked out of the 5’ tree tube during the heat wave and looks happy.

Black currants are a complete loss, as with most of the goumi. Honeyberry and blueberry don’t seem to have minded much.


Not many suggestions. In Arizona we took “full sun” to mean “partial shade.”

Out of the three pawpaws I had planted this winter, one looks great but the other two have significant leaf damage even though they only get about 3 hours of direct sun in their spot. The leaves look oven crisped.

My loquats melted a few times during the heat wave, but revived when I set a hose dripping on them for a bit. No real permanent damage, only a few small crispy leaf corners.

My cold hardy banana and avocado seedlings mostly loved the heat!

Though even the older banana leaves burned a little:

My feijoas also loved it, with all my surviving grafts pushing new shoots now.

My red raspberries turned to sour mush.


Yeah, by total loss on the currants, I mean this year’s fruit. The plants look fine.


suprised the honeyberries did ok. they wilt bad here in temps over 85f but we rarely see more than a handful of days over 80 so im sure they have adapted to that.

@Bear_with_me ,
Figs were hardly affected by the heat, maybe a bit of scorching on young tips but overall not bad at all.
Main crop set is heavy on all varieties – whether pinched or not. If we continue to get warm weather I expect to have a good main crop this year
Desert King breba might be advanced by 2 weeks compared to last year. Maybe mid July for the earliest fruit.
Next time we are expected to get this sort of intense weather, I will follow the advice I heard on a different forum – spray Surround kaolin clay on all the fruit and leaves.

@Bradybb, extreme weather events are more likely than not in the future due to man made climate change. This is not just an opinion but scientific consensus.

Disturbance in jet stream can result in extreme weather both in summer and winter – this is what caused the extreme events as far south as Texas.

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Bear_with_me and other friends.
You are not alone with this problem, here in Spain in my region the extremely hot and dry weather in summer would make many of my crops impossible, if I did not use an extremely cheap, extremely easy to use and extremely effective product.
The product that I use is called " Blanco Natural " ( Natural White) , this product:

  • Blanco Natural :

Blanco Natural

Data sheet :

It is neither more nor less than a mixture of micronized clays, fundamentally Kaolin (for use by foliar spraying mixed with water), or ground, (for use in powder), which reflect the solar radiation of the leaves, and avoiding the dehydration of the plant .
It is such a simple and very effective mechanism.

I recommend the use of the micronized product for foliar spraying dissolved in water, since it adheres better to the leaves, two treatments are carried out in summer, and the result is incredible.

These types of products are also for sale in the United States, and they are totally ecological.



Thank’s a lot! That’s good to know! :+1:

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Interesting. I have an unopened bag of Surround brand kaolin clay in my shed.

I wonder if it would have helped my new Cardinal persimmon shoot.

Translucent tree tubes seem like they may have provided some protection. I’d put some chicken wire around it to protect the delicate growth from rabbits. Had almost used a tube instead but didn’t have one handy at the time.

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Yes murky, the “Surround WP” trademark product is entirely suitable, as indicated by its manufacturer:

Do not worry if the fruits of your trees they are covered with white powder, since it is totally harmless for humans, and tremendously easy to clean after harvest.
This product has two functions:

  • It has a good insecticidal effect
  • It has a very high effect to avoid heat stroke in fruit trees, since it reflects solar radiation and prevents dehydration of the plant, totally avoids what in the United States you call “Leaf Scorch”.

If you have not used this product, you will be surprised by its effectiveness.


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Hello Jose! It can be used in all fruit trees? Citrus too? Thank’s! :+1:

Luis, in citrus fruits, is doubly suitable, since it prevents the attack of the Mediterranean fruit fly (Ceratitis Capitata), which strongly attacks citrus, as well as its protective effect against heat stroke.

Curiously, the first product of this type has a North American patent.

This document from 2006 says:

Kaolin is a clay [Al4Si4O10 (OH) 8], registered in the United States for the control of pests (pear psylla, thrips, leafhoppers, curculionids and citrus fly). Its use is also authorized in Spain, Italy, Greece, Argentina, New Zealand and Australia to reduce “sunburn” and thermal stress in crops.

It’s a really good, cheap, and very effective product.




There are varieties that are extremely sensitive to heat stroke, for example, kiwi, hazelnut, or walnut (especially the good French varieties such as Fernor), some of the walnut varieties of Californian origin are more resistant ( for example Chandler), but generally walnut is quite sensitive to heat stroke.
If you do not use this product in the central and southern states of the United States, many crops will give problems due to sensitivity to dehydration by solar radiation, mainly in the most youthful state of the sensitive varieties.


When we were talking,not too long ago,was it your opinion or scientific evidence,that Summers around the Seattle were going to be mild and the very hot conditions were going to stay further south?