Some diseases- health has nothing to do with fighting FB, or black knot, or CAR or scab or mildew, or…
Health will help a tree survive some diseases but not always help save a crop. Vigor makes it possible for trees to close off wounds more quickly and provides stored energy in the wood so if foliage is destroyed a tree has better reserves to regrow its canopy. Often death is the result of energy depletion and vigor is both a sign and producer of a good fat energy bank account.
The great horticulturist, Carl Whitcomb, has written about “thrifty” plants surviving transplant well and the term applies a good supply of energy reserves as a result of good vigor before transplanting.
A vigorous tree heals grafts very well also and I’ve gotten 4-5’ of growth in the first year of grafts on really vigorous, mature apple trees.
Alan,
Once in awhile I get that super vigorous scion that outgrows its rootstock. I always wonder what makes their genetics so much better than everything else. Formerly I thought it was a hidden virus causing some trees to grow better than others. There was a time when I thought it was triplods vs diploid genetics responsible. I’ve came back to the conclusion there are times I don’t know why some plants are healthier than others. If we can ever pinpoint the reason why one tree thrives in the same location another dies we will be closer to having the answers we all want.
My tip is one most are probably aware of, and really only applies to us northern folks, but reminders never hurt. Cover the ground around fruit trees with a thick layer of mulch late fall after the ground is well frozen. Having, say, a foot of leaves or straw or wood chips on the frozen ground makes a huge difference in how long it takes to thaw and warm in the spring vs. bare ground and can delay bloom by weeks. Last year my pear trees had no mulch around them and got going about the same time as my asian plums. This year I was more careful to mulch them well, the plums are waking up and swelling while the pears are still tight and quite dormant. Bonus tip, never give a kid in a swim diaper a piggyback ride. . . . trust me.
I am not sure this is true, I don’t believe apple or other fruit tree’s bud emergence is affected by a heavy mulch although I can’t find any research supporting this or not with a quick search. I believe I have seen such research in the past that proved the futility of mulch for such delay.
It is common sense that if this worked it would be standard practice in commercial orchards in the colder regions, it seems to me. It certainly is a discussed topic in the industry.
The mulch reduces radiation from the ground, which protects buds, so at the very least, the mulch needs to be raked away from beneath the canopy preceding threatening cold after bud break.
You can take cuttings from black raspberry canes in late fall thru early spring . They root easily . Just plant them in pots or the ground . Red raspberries you can take root cutting to increase your plants . Useful to increase a new variety
My memory of delaying bloom research was there were some studies showing root temps are not a factor, its all in the canopy wood temps. For example clip off a limb of buds and bring it in and put it in water, it will bloom right away with no roots at all.
It’s the flower bud temps that we’re concerned about. Bloom can be delayed by keeping the flower buds cooler as for instance via evaporative cooling. Spray the tree every 5-10 minutes with water whenever air temp is above 40F.
So this isn’t necessarily a tip but more like a proposal for an experiment…which, if it works, may graduate into a tip, LOL.
Whereas there are many reasons to delay bloom (reduce frost vulnerability, timing of polinators, and maybe others);
and whereas the action needs to be applied to the canopy;
and whereas acceleratiing forces both radialtive (sun & ground) and conductive (air) are available all winter. Why not try the following next dormant period…
Spray a coating on a few dormant branches on various trees which is both reflective (white?) and insulating (by virtue of its thickness) and compare the results with other branches.
It sounds like the coating Surround may be a candidate. I’m thinking of trying a dilute gypsum (plaster of Paris)-like spray.
Your thoughts?
Or maybe I should place this post elsewhere. (Newbie error?)
Well Alan, is the winter sun not heating the bark and surrounding air, esp during unseasonably warm spells? That is what the wood would need to be insulated from. Or maybe I don’t understand your point.
I think Alan’s point is that a coating will provide very little insulation, whether it is trying to keep heat from moving out (for example, protecting against cold) or prevent heat from moving in, which I think is what you are proposing.
It is recommended to paint the trunk with white latex paint to prevent southwest injury, which is caused by the sun warming the trunk, followed by freezing temps which then split it. So, in a sense, many of us already do what you suggest regarding reflective material with part of the tree. Well, you will have to give it a try and report back to us on what happens.
The sun does heat flower buds above air temperature causing the tree to bloom earlier. A reflective coating, under the right conditions, could potentially reduce bud temperature and delay blooming a few days.
Well, what I was thinking is to use something that buffers the temp. I’m not sure whether the radiative or conductive pressures are greater. That’s what experiments are for, LOL. The tree does not generate heat, it absorbs it, which is what we want to delay, which will hopefully delay the buds - that is, it will act to buffer temps even delaying bud formation. Reducing the heat transport into and out of the limbs may reduce stress on them the way @northwoodswis4 uses this on the trunk, but hopefully in this application delaying bud emergence.
We had a warm spell in November and my Anna apples started blooming. I was mulling over this problem back then and thought surely this group had tackled this, or, could come up with a better experiment.
It seems to me like the problem is lowering the temperature enough to get the tree to delay bloom for a few weeks. Most of the trees that I have that bloom early here are not damaged by the last hard frost of the season. I would have liked my peaches to hold off blooming this year unto April 15. But they started blooming about three weeks before that. I think of what it takes to raise the temperature just enough on a few nights in the spring to save the blooms. To lower the temperature for a much longer time seems like it would be very difficult. I really tried to look at little microclimates that I might have on my property that would give added heat to help save the blooms or cool spots to slow bloom development but I believe they would not be enough to really make a huge difference. Fruitnut has really done a great job of creating an environment he can control to get chill and protect from frost and it is expensive and has space limitations.
Reflecting heat it can do, but the word is not insulate. I’m not trying to be combative, just trying to promote clear understanding- in my own mind as much as anything.
If you think about it, it really would be a hard practice to implement commercially. First you need a massive amount of mulch, then you have to go in with trucks, tractors, bobcats and spread it around after the ground is frozen, then remove it again the following spring after frost danger has passed ( if you leave it, it would insulate the ground the following winter and not let the ground get as cold/frozen) If I’m growing a fruit crop that gets frost damage 1 out of 5 or 1out 6 years commercially, don’t know that I would want to put out that cost every year. But a backyard home orchardist could do so pretty easily.
Everything I’ve seen shows that root temps do matter. My experience with the pears stated above, also seeing trees in pots or whiskey barrels wake up way earlier than the same trees planted in ground. Heres a link from the University of Illinois extension https://web.extension.illinois.edu/dkk/eb266/entry_10942/Home orchardists can do a couple of things to reduce the risk of a late frost too. You can delay the spring growth of your dwarf fruit trees by mulching the soil in early winter well after we have had cold weather set in and hopefully after the ground is very cold or even frozen. This activity will keep the ground frozen and the root system cold and delay the fruit tree from breaking dormancy even by a few days, helping us get past the chances of that late frost.
One last thing I’ll say in closing, respectfully, but If you clip a branch off and bring it inside, or leave it outside for that matter, then yes, root temp doesn’t matter only because they are no longer connected. If you think about it temperature is conductive, hot and cold. If I have a block of ice in my house with, say, a pencil sticking out of it, the pencil will be quite cold, even if I turn the air temp up to 80. If I separate the pencil from the ice it will warm up much faster. Likewise a bud, connected to branch, connected to a trunk, connected to a huge root system in frozen, or very cold soil can stay cooler. Mike
In thinking about it a little more, the size of the tree probably makes a huge difference in the effectiveness of mulch. Back to the pencil sticking out of the ice illustration, if its say a 13 inch pencil the air will be able to warm the tip up quicker than say the tip of a 4 inch pencil. So for a lot of our small backyard dwarf fruit trees keeping the ground colder longer has a big effect, the bigger and taller the tree the less effect I suppose it would have.
