Author Topic: The looks of my trees after winter  (Read 4641 times)

Sven_limoen

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The looks of my trees after winter
« on: June 14, 2014, 06:10:33 AM »
Hey everyone,

My lemon and orange tree look like this after winter:





Always the lower leaves dropped and the upper ones remain. Well at least some or in the case of the lemon tree: 3.
What should I do with these trees? Cut them down to give way to new shoots or just leave them like this?

Kind regards ;)

swimmingfree

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Re: The looks of my trees after winter
« Reply #1 on: June 14, 2014, 07:39:51 AM »
i live in Michigan so i have to bring my tree in for the winter ... the leave fell off for ether to munch water or not a nuff water..  i have all most kill mine more time then i can count ... i put it out side in the sun and see that happen then cut off the dead wood in the fall when i bring then back in ...
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Sven_limoen

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Re: The looks of my trees after winter
« Reply #2 on: June 14, 2014, 08:12:52 AM »
Mine are on a heat cable during winter inside. Next year I'll raise the temperature and hope I'll get a better result.

No deadwood for now on the trees. Just bold branches :)

Pancrazio

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Re: The looks of my trees after winter
« Reply #3 on: June 15, 2014, 10:06:32 AM »
I would leave like this until they show an increased vigor. Then i would top them. I think that they issue can be the lack of light, so give them all the sunlight you can.
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Sven_limoen

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Re: The looks of my trees after winter
« Reply #4 on: June 15, 2014, 10:56:01 AM »
I would leave like this until they show an increased vigor. Then i would top them. I think that they issue can be the lack of light, so give them all the sunlight you can.

Increased vigor being new shoots? The branches are already topped from long ago. The only thing I could do is cut them even more down.

Pancrazio

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Re: The looks of my trees after winter
« Reply #5 on: June 15, 2014, 08:18:45 PM »
Yes, i mean new shots. You don't need to reduce the amount of leaf because the plant probably has already a low photosynthezing surface, and you don't want to reduce it even more. Just give it all the sunlight and heat that you can, using this summer to make it stronger, on next spring you can, if the growth as been enough, lower it if you want.
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Millet

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Re: The looks of my trees after winter
« Reply #6 on: June 15, 2014, 11:04:15 PM »
I do not know at what temperature you keep the tree's root system during the winter, but if you place the tree in sunny location, AND keep the roots at 70F, throughout the winter months you will not see leaf drop.  Best of luck to you and your trees. - Millet

Radoslav

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Re: The looks of my trees after winter
« Reply #7 on: June 16, 2014, 01:09:10 AM »
Your trees look exhausted. I did not catch the idea of heating cable indoor?
My guess is, that Belgium has nearly the same amount of sunlight like Slovakia during winter, so it is necessary to keep trees in cold place with temperature not higher 10 Celsius. Also watering can be very dangerous during winter! I do not water citrus trees during winter, I water them only in case if they really show marks of drought - bowed leafs.

Sven_limoen

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Re: The looks of my trees after winter
« Reply #8 on: June 16, 2014, 01:28:32 PM »
Your trees look exhausted. I did not catch the idea of heating cable indoor?


I wanted to keep the soil temperzture up to lower the risk of WLD.

Sven_limoen

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Re: The looks of my trees after winter
« Reply #9 on: June 16, 2014, 03:02:02 PM »
Ow yes...what do you mean with exhausted?

Citrus-addict

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Re: The looks of my trees after winter
« Reply #10 on: June 16, 2014, 04:36:27 PM »
I have had in the past trees like this after the winter, with warm weather they grow new many shoots and are fine , quicker results by warming the roots and spraying with dilute fertiliser every day.

I now no longer have any winter leaf drop problems as all trees are kept with roots at around 30C as recommended by millet years ago on the other forum

Millet

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Re: The looks of my trees after winter
« Reply #11 on: June 17, 2014, 01:02:01 AM »
Winter Leaf Drop (WLD) Occurring With Container Grown Citrus trees.  Here is a preview to an upcoming article in the California Rare Fruit Growers Magazine "Fruit Gardner" about this problem.

Many people seem to have problems during the winter with their citrus trees. There is a phenomenon that affects citrus grown in containers know as Winter Leaf Drop (WLD), which is what happens to the trees during storage in winter quarters.  With the appearance of fall and a decrease in temperatures, the trees are brought indoors to protect them from freezes and frost damage. 

Unfortunately, the most common recommendation freely given for storing the trees indoors is as follows:

"Give the tree as much light as possible, keep the medium moist, but never over water.  Let the medium dry out more than in summer.  Hold the tree at temperatures around 41 - 50 F (5 - 10 C)."

 If you have followed this advice and have had no problems, you are lucky because most people who did so had problems.  The trees start to shed leaves, leaf after leaf drops, and in spring, after the last frosts, when the trees are placed outside again, many trees have few or no leaves remaining on the limbs, twigs and branches.  The cleavage is often between the leaf petiole  and the leaf blade, the petiole remaining on the tree. Often the dropped leaf shows no chlorotic patterns or any other discoloration.  Our first thought is that Winter Leaf Drop was influenced by low-light conditions during winter times. But even with extra illumination Winter Leaf Drop continued.  Often, after bright, sunny mid winter days, more leaves are shed than after longer periods of less bright light.  So we tried to find out what might be the cause of Winter Leaf Drop.  We chose five lemon seedling trees, all about one foot high.  The seedling trees were placed in different locations with different conditions:

1. The first seedling tree was placed in a cool and bright location at a south facing window, at temperatures around 43 -50 F (6-10 C).

2.The second seedling tree was placed in the same room, but at a north facing window.

3. For the third tree, we chose a temperate room with temperatures around 59 F (15 C).

4. The fourth tree was placed at the same temperatures but on a south facing window.

5. The last plant was placed in a warm room of 70 F (21 C) at a south facing window with extra illumination.

All trees were irrigated as needed, just to keep the root ball moist, but not wet and not allowed to dry out.  Only #5 was irrigated more regularly and fed evenly.  After winter we found that #1 shed nearly all its leaves. #2 dropped some leaves only, and the others had only lost some (fewer than five) or no leaves.  We found light may NOT be the factor causing WLD, so we thought about temperature.

After a long discussion with citrus experts in Florida and Israel, it was found that temperature will cause WLD. The temperature tables from the book Biology of Citrus show that citrus stops root growth and root function if the soil temperature drops below 54.5 F (12.5 C).  Leaf activity will be reduced if the temperatures drops below 64 F (18 C).  Leaf activity means the full process of water evaporation for leaf surface cooling, energy transformation (photosynthesis) and starch reduction for building amino acids and other compounds for forcing plant growth and cell development.  Citrus controls its leaf temperature by evaporating water from the leaf blade.  This reduces the temperature even during hot periods and will maintain the leaf temperature at the optimum levels between 77 F (25 C) and 95 F (35 C).  But even on cold days the sunlight can heat up the leaf surface quite quickly to levels beyond the critical temperature of 54.5 F (12.5 C).  Photosynthesis itself works better in cooler conditions with high light radiation than in the warmer periods of the day, so most of the photosynthetic starch production is done in the morning before noon and less water is evaporated than during the afternoon.  Optimum leaf temperature for photosynthetic activity for most plants ranges from 50 F (10 C) up to 90 F (32 C). Photosynthesis itself  needs carbon dioxide, light and water to transform the carbon dioxide into starch and oxygen. During the night the starch will be oxidized to provide energy needed for plant growth and development. The whole process is called breathing. Water and nutrients for the breathing process must be taken up by the roots.  Oxygen and carbon dioxide will be delivered from the air around the plant, taken up by the leaf surface (and to some extent by other green parts of the plant) so leaf and root activity must run in a balance to provide the best plant performance for growth, flowering and fruit development.  If a citrus tree is stored at temperatures below 54 F (12 C) but gathers enough light for photosynthesis, this balance is broken.  The leaf activity requires water, which the roots cannot deliver.  The tree stops evaporation and water will be unavailable for cooling the leaf surface on bright days, so the tree reduces active leaf area by leaf abscission.  This seems to be the best theory about what causes WLD.

Partial or complete defoliation was never critical if the root ball was kept  a little more on the dry side, but if it was too wet, a quick root decline developed even if Poncirus trifoliata was used as a root stock.  Most of the trees recovered quite will in spring (if the roots stayed healthy and a heavy bloom was set).  But in recovering the whole canopy, often the trees used up much of their starch reserves in the stock, which did not fully refill during the short summer times.  After some years, many trees suffered, growth was stopped and the trees died because all of the starch had been depleted.

So what to do about WLD? Irrigation during wintertime seems to be a recommended practice to slow down WLD. Irrigation with warm water 77-90 F (25-32 C) supports the root function, even the water uptake, so WLD will slow down.  Irrigation reduces the plant stress during cold winter time and is therefore recommended.

Keeping the trees in a room with high humidity seems also to slow down WLD but cannot prevent it.  Also a place more in the shade, to minimize  leaf activity, slows down WLD. Keeping the root temperature below 64 F (18 C) but at or above 59 F (15 C) seems to work best for stopping WLD.  The plant functions are minimized, but water and nutrient uptake for leaf activity is high enough to support the breathing process and leaf surface cooling by water evaporation.

If WLD persist, force the root temperature higher, around 70 F (21 C) this should stop leaf drop.  Sometimes during the winter, fruits dry out on the tree and drop if the tree is stressed too much.  So for fruit development and fruit maturity, higher temperatures and good leaf activity should be maintained.  Irrigation with a nutrient solution should be done even in winter.

Hope this helps - Millet


Sven_limoen

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Re: The looks of my trees after winter
« Reply #12 on: June 17, 2014, 01:12:11 PM »
I also used this text to try to at least limit the WLD. It seemed to work pretty well on my calamondin but not on the latifolia, limon nor sinensis.

I had the containers heated at about 20°C on the edge of the pots so I guess the temperature in the core would be around 16 to 17°C.
They were stored in an upstairs room with only a small roofwindow but no direct sunlight on the trees.