What's wrong with my trees?

I have four dwarf citrus, all planted on a west-facing slope and watered via drip. They have been in the ground since Feb 2007 and have produced no fruit (that's issue #1). Also, for the second year the leaves are brittle and point toward the sky (that's issue #2). As you can see, I am getting yellow veining now, and someone (probably a grasshopper or five) is eating happily. So -- what can I do to make these sad plants happy? I'd love to have some fruit this year or DH may chop them all up for firewood. (BTW -- I have 2 Meyer Lemon, a Satsuma Mandarin, and a lime and they all look more or less the same.)
Thanks for your expertise!
Stephanie

This message was edited Nov 1, 2008 8:30 AM

Citrus have very fine roots that grow close to the surface. They require moist soil with good drainage. Water is reapplied when the top 1 - 2" of soil is dry. Any dry periods will damage or kill roots and stress the tree. When planted on a slope, trees will grow best if they're planted on level ground so all the roots get water and oxygen. Build a semicircular retaining wall at least as large as the radius of the mature tree's radius and fill with good top soil. It's also easier to harvest fruit on level ground. Deep watering will encourage the roots to grow deeper. If the trees go on a drip system, a number of emitters would have to be spaced out around each tree so the entire root system receives water. As the roots spread out, bigger rings of emitters would have to be added. The emitters would have to be left on long enough for the water to penetrate down several feet.

Your tree are probably not getting enough water. This accounts for the heavy leaf drop and curled leaves your tree exhibits. You didn't mention how often you fertilize and with what. Also have you tested your soil's pH? I mention soil pH because yellow veins could be a deficiency of sulfur or boron. Both deficiencies can arise in highly alkaline soils or when too much lime is added to the soil. Use citrus fertilizer which contains the micro-nutrients citrus trees need.

Western exposures are very hot and can be damaging to to the thin bark of citrus trees. Check the bark for damage. If the bark is undamaged, you can protect it by using a wash make of 50% water and 50% white latex paint. You need to get the trees back to a healthy state before asking them to produce fruit for you. Remove any flowers they produce. The trees need to concentrate on getting healthy new leaves and growing well.

You may find this article helpful. It comes from Arizona, but it easily applies to southern California.
http://ag.arizona.edu/pubs/diseases/az1154/#envrn

You may not be able to do anything about the soil level, but you have to improve the watering situation. Check the soil pH and consider having the soil tested. If the pH is above 8.0, use agricultural sulfur to lower the pH. It will take time to do so checking the pH often. If the soil is naturally highly alkaline, you will have to continue the addition of sulfur as directed on package. Don't fertilize immediately. Instead use a product, such as SuperThrive, that encourages root growth. Then in a few weeks apply fertilizer at half the recommended dosage. Protect the bark with whitewash. Remove any flowers so the energy will be redirected toward producing leaves. Don't expect complete recovery immediately. That may take years depending on how damaged the roots were. I once had a Eureka Lemon left in my DH's care for a week. It went without water for a week and lost all it's leaves. It took years before it became a bushy tree again.

Another important thing is to keep the ground under the trees free of all other plants and grass. They compete with the trees for water and nutrients. Just remove anything in a circle one foot past the drip line.
Oldude

I am not sure whether I have the same problem. I am in New Orleans, planted my citrus (Meyer Lemon, Ruby Grapefruit, and Persian Lime) slightly high to keep roots slightly above water line when it rains. I've had problems with leaf miners several times since planting in October of 07, but weren't able to catch them in time. I removed all buds but one on the lime tree ...there were massive amounts, but not many leaves this year.

Four days ago about half of the leaves on the Meyer Lemon turned bright yellow and about a third dropped. Only a few dropped on the other trees.

I admit I allowed bermuda grass to creep into the one foot root zone around the trunk, because I was afraid that pulling them might harm the roots.

Hopefully you can tell me what the problem is. Thanks for any help.

Sarah

Bermuda grass has been a thorn in my side since moving to Texas. Because their roots start so close to the surface, the cleared area around citrus needs to start off at about 3' - 4' in diameter and get larger as the tree grows. Bermuda grass is so deep rooted that it is very difficult to get rid of. In ornamental bed, Ornamec will temporary kill Bermuda, but it's not for use with edibles. You can spray the Bermuda with Round-Up taking care to protect the citrus trees.

Yellowing leaves have a number of sources. So you have to sit down and examine you citrus gardening practices. Citrus prefer moist soil, but the drainage has to be very good as the roots are sensitive to overwatering, the most common cause of yellow leaves. In areas that are prone to lots of rain at times, the drainage must be excellent.

If the trees have gone dry repeatedly, the leaves will turn yellow. During a drought, I have to use a sprinkler to water well beyond the rootball area. Otherwise the trees never seem to get enough water.

Yellowing leaves also indicate nutrient deficiencies. Fertilizer for citrus is determined by the diameter of the trunk and is divided into 3 or 4 feedings a year. Since citrus grow in spurts instead of continuously, you need to time the feedings to coincide with the spurts and feed them just before that spurt. I find it safer to use a fertilizer designed for use on citrus, one that includes micro-nutrients.
http://edis.ifas.ufl.edu/SS420
An excellent guide to nutrient deficiencies with photos:
http://edis.ifas.ufl.edu/document_ch142

Yellowing leaves and leaf drop can occur in winter. It is a normal process and doesn't indicate a problem. If you rule out all the other causes of yellow leaves, this could be the reason for the yellow leaves and leaf drop. Sometimes plants are confused by a very hot summer, followed by a cool period then by a warm period again. We had a cooling period in early October before getting warm again. A number of spring blooming plants are sending out a number of blooms. If your citrus have experienced such a cycle, yellowing leaves are possible. This link explains yellowing leaves in winter:
http://cekern.ucdavis.edu/Custom_Program143/Yellow_Citrus_Leaves_in_Winter_Usually_Not_a_Disease_Symptom.htm

Bettydee--
Just returned from a trip to see your great advice. Thanks so much -- I have worried about the water situation and what you say makes sense. The trunks look fine but I'll paint them anyway. We have had some hot, dry winds recently and I'm sure the poor guys are stressed, as you say. I'll let you know the results!

I'll be interested in seeing your results.

Thanks Bettydee, I pulled the bermuda to a radius of 24 " from the trunk of all three citrus trees, then I sprinkled with an organic fertilizer and added an inch of soil ammendment and topped it off with some pine needle mulch.

We did have warm weather followed by cool weather, followed by another blast of hot weather. That could have been the reason, but I think removing the bermuda will help too.

My Dad just brought me two neglected citrus trees, mayer lemon and valencia orange. A friend was about to toss them out.
My son planted them both. I gave them some citrus fertilizer. They both have no leaves at this time. I did not have a chance
to see the roots. I read all the above info. that will help me out a lot. Any more advice would be greatly appreciated.