Tangerines often look kind of sickly compared to other citrus. Looking at pic #3, it looks like it may be planted too deep, and they sure don't like wet feet. Have you tried a minor element spray? There is also the possibility of Burrowing Nematodes if you're living on land that was once a citrus groove.
john

In my opinion, or what I would do if it was mine.
I was raised in FL. smack in the middle of a grove. Citrus trees in that grove and every one I have ever seen,
1] planted in sand, water would pass right thru around the tree.
2] I think the worst thing you can do is use any kind of mulch
3] Never use any kind of compost, the soil around the base of your tree looks very rich.
I would take a heavy duty garden rake and pull back all that mulch and vegetation at least 6' around the tree. Forget the cow poop, compost and liquid fert. Put one cup of plain old 6-6-6 all around the tree, scratch it in and then the best thing to do is leave alone, step away, it will get all the water it needs for the next 3 or 4 months from mother nature..
Plant em if you got em.
Sam

I thought citrus liked a slightly acidic soil?
& you do not say how it was planted - that can make a difference too. Too deep or too shallow & whether the planting hole was amended, etc. - whether the roots were potbound & if so, were they broken apart before planting?

Are you using reclaimed water? Might there be salt intrusion?

& then there's the possibility it might be inferior stock - you do not say what variety it is....?

FWIW, I have all my citrus trees mulched around the base - but the mulch(mostly oak leaves) is kept away from the trunk & they do fine w/that - & I use compost, organic fetilisers(bone & blood meals, alfalfa pellets), etc.
I do try to keep the ground free of any growth to the dripline, tho. I understand commercial growers can grow in pure sand coz they basically run life support - lots of artificial ingredients & they need to be able to move machinery between the rows as well.

You might want to contact your county extension office - they're happy to help & have loads of resources & very smart people.

& finally, UF has lots of info - this 1's on culture: http://edis.ifas.ufl.edu/hs132 & here's a troubleshooting article:

Here is a link that might be useful: Citrus Problems

I stand by what I said, pull back with a garden rake all foliage and mulch, then fert with 6-6-6 now stand back and leave alone. Thats what I would tell a friend or family member to do. Good luck.
Plant em if you got em.
Sam

I'm not a citrus grower, other than my own 9 trees, but I had a tangerine that didn't bear for years. One year, a friend told me to fertilize it monthly instead of four times a year, just like my Lemon. I did, and it's had a bumper crop every year since. This year, I thought all the fruit had blown off in the spring storms, but I counted over 20 fruits on it.

Just as an experiment, I started fertilizing all my citrus that way with a little every month, and I've never had so much fruit, or such healthy looking trees. Can't help to try it.

Oh, and I've always been told not to have anything growing under a citrus from the trunk out to the drip line, but my friend has bromeliads growing all under her trees, and they do fine. I think the bromeliads don't suck up as much fertilizer as other plants.

Thanks all for the feedback.

I removed all planting around the tree, removed the mulch and raked the soil around the trunk it was probably planted a bit too dip. I will check on the fertilizer and sprays after

Hopefully this will help!

We have a tangerine tree over 45 years old, lots of fruit, but the leaves are curling up.looks like its dying, Can you tell me whats wrong, or what i can do to help it.Its taking longer for the fruit to get sweet.. HELP !!!!!!

Linda,

At 45+ years that sounds like normal age decline of citrus.
They do not have as long a bearing life such as other fruit trees.
The estimated productive life of citrus trees (limes 25 years),
other citrus is 36 years as established by the Florida Agricultural Statistics Service.

I would recommend planting another while you are still getting some production from your older tree.

Lou

Gopher - I had a tangerine with the same problem. I surrounded it with circular stones and fertiised it with Citrus Fertiliser from Home Depot. This year (last year) it bore for the first time, thirty, I intend to fertilise it again this coming Spring. They were big and juicy too.

3 year old sunburst tangerine that has never flowered! Additionally the leaves have rust colored splotches on all of the up or sun side of the leaves. The tree has been fertilized and watered via the recommendations of the U of Florida.