I am a newbie citrus fan and in need of some serious help. I have 2 dwarf Yuzu I bought from Four Winds Grower a year and a half ago (they were 3 year old trees). They were doing fine until about 6 months when many of the leaves along a few branches would suddenly turned yellow starting at the base and dropped. Some of the leaves dropped leaving the petiole, which would later also drop in the next day or two. Some of the branches retained the top most leaves, leaving the middle devoid of leaves. Some of the branches completely lost all leaves and the died. I also have a dwarf Kaffir lime tree and a dwarf Rangpur lime tree I bought at the same time, also from Four Winds. The Kaffir is doing great. The Rangpur would not stop flowering, and in the past month had a few leave drops (not as much as the Yuzu), some leaves are yellowing, and did not have much vegetative growth since purchase even though I pinch off most of the flowers. This is what the Rangpur look like right now: Here is some relevant info on the plants: 1. They are container plants, and have not been repotted since arrival. 2. They are indoor only, and I have two 250w equivalent CFL, 6500K Full Spectrum bulbs in floodlight reflectors on stands. They are on from 6am to 8pm. I just added the LED panel from Aero garden a few days ago. I rotate the plants every few days so all sides get light. Here is the setup: 3. For the first 8 months, I only fertilized them sporadically. But for past 6 months or so since they weren't doing well, I fertilized them about once a month with Jobe's Organic Fruit & Citrus Fertilizer (3-5-5). This initially stopped some leaf dropping and there were a little spurt of new leaf growth on the top of the Yuzus, but the fertilizer seemed to have made all the trees flower, and I am afraid they are too weak to flower right now, so I have not applied any fertilizer in a little over a month. 4. I water the trees only when the top two inches of soil feel dry, then I water deeply and don't let them stand in any water on the trays. The soil still drains pretty quickly - starts draining about 1-2 minutes in after watering and stops after about 5 minutes. About 3-4 times a year, I bring them to the bathroom and give them a good rinse with the shower head with gentle pressure. 5. The trees are kept at ~72-85 F all year round. In the winter, I have a humidifier that keeps the room humidity at about 35-40%. 6. Currently, the soil pH is 7 and the soil temperature is 75F. (I use a digital soil pH meter, so I know that's not very accurate.) Here are my questions: 1. Is the lack of light an issue for the trees, causing the leaves to drop and the branches to die off? I have replaced the old CFL with new ones and added another LED panel a few days ago, will this help? 2. I read that the way the leaves are yellowing (see picture), it could be Magnesium deficiency? Does this look like Mg deficiency? Or is something else going on? 3. The branches that died off on the bottom, will new leaves or branches grow from that area? Or will my plants forever look leggy and misshapen? Anything that can be done to help? 4. Is the amount of time I leave the lights on ok? Should I vary it by season? Will changing the amount of time the light is on affect vegetative growth vs. flowering? 5. Should I use a different fertilizer to promote leaves and root health? If so, what should I use? Is the fertilizer that I'm using right now pushing these weak plants to flower? 6. This is the most important one: I want to repot all the trees. When is it a good time to do it? My concerns are: A. The Yuzus are so weak right now, and one of them has some new growth on the long leggy area where leaves had dropped before and they are still yellowing and dropping leaves. Is it ok to repot them in this conditon? B. The Kaffir is bearing fruits right now, should I wait until after harvest to repot? That will probably be in the fall, is that an ok time to repot or does timing not matter as much if they are indoor only? Should I pinch off all the fruits now and just repot it right away? C. The Rangpur flowers all year long, and it's currently bearing fruit. I'm not sure when it is a good time to repot it. It is also looking a little weak right now, have not had much growth since it arrived and there were a lot of fruit drops. There are currently about 4 decent sized limes on it but the tree is small, should I remove the fruits and give it time to grow bigger? 7. When I repot, what is the best potting mix to use? I love these tree so much, any additional tips and recommendations will be very much appreciated.
I don't know the reason behind the yellowing leaves but the fact that they are dropping and leaving the petiole behind is a sign of stress to the tree. Here are some thoughts on your questions, numbered according to the question number: 1. An increase in light couldn't hurt; it's worth a try. Is there a spot behind a south- or west-facing window where a tree can be placed? If so, perhaps you could move one of the problem trees there and see if the situation improves. 2. A comparison of your photo with the one in the the document that follows suggests it is not a magnesium deficiency. Reference: HS-797/CH142: A Guide to Citrus Nutritional Deficiency and Toxicity Identification 3. I think leaves will grow back if the tree is given enough light. My initial though was to cut back the long branches but that would remove all the leaves near the end which would further weaken the tree. Perhaps it would be best to leave it alone until the tree has recovered. 5. Citrus should be fed regularly using a high nitrogen fertilizer when they are actively growing. A fertilizer with an NPK ratio of 5-1-3 is recommended for containerized trees. Micronutrients should be included in its formulation. 6. I would not repot the problem trees until they have recovered. By the description in point #4 the current medium appears to be quick to drain and so should not be a problem anyway. 7. The medium should be porous yet moisture retentive. One approach is to amend a standard peat-based indoor soil mix with ingredients that which increase its porosity. This could be a combination of things like bark chips, perlite, and calcined clay. Another approach is to use coconut husk chips (CHC) as a medium. The choice is a personal one. I have a tree that suffered leaf loss and branch dieback last autumn (though the leaves did not yellow like yours). Problem turned out to be insufficient light; moving the tree closer to the window solved the problem. I don't use artificial light so I can't say whether that is your problem. Since not all your trees are affected perhaps there are cultural requirements specific to the yuzu trees, less so the rangpur, though I can't think of what that may be.
Hi CLai! My opinion is the answer under term Yellow vein chlorosis might be worth of research for you and for your tree. It is obvious from the pattern and from leaves position that there is a question of a lack of some of mobile micro or rather macro element that is prevented to be absorbed by the roots or it is not absorbed in quantities that are needed for a new growth on your Yuzu. I would guess the lack of nitrogen is in question. The answer why this occurs you can find under the search of previously mentioned YVC (Yellow vein chlorosis). While Rangpur tree on the picture under Yuzu tree pictures, clearly shows the signs of a beggining of root rot. If I were on your place I would immediately check the condition of root tips (those must be firm and light color - white, not mushy and in any shade of brown) and on your Rangpur tree, the problem in this case might be found in either over watering or salt intoxication of root system in either case the problem is in a not suitable growing medium which plays vital role in root health. On the point 6 I would not completely agree with Junglekeeper as if there is any sign of root rot present the sooner you repot the better for a tree. I would remove any fruits from your trees as trees are in a shock and pretty young so take care of them in the first place, healthy trees will return you your care in the future. The fruits will not develop much more and because new growth season is almost here the fruits that are present on the tree at the moment will influence the number of the formation of flower buds and increase june drop in following season which ultimately means less fruit. It is a good time to repot, repotting must be done while tree is still dormant but rather than in autumn should be done at the end of winter right before new growth flush appeare.
