The unknown tree is probably a camellia. (Google some images to confirm, because I tend to be wrong). Every so often a leaf will die and isn't anything to worry about.

In general you're probably okay watering once or twice a week until you get some actual diagnoses (some of the curling looks a bit off), but they don't look that bad and you definitely bought a nicely planted home. Hope your unknown is a nice navel or mandarin!

Don't worry too much about the persimmon leaves. Just don't be surprised when they all fall off. :)

Your trees look fairly healthy to me, but they do need fertilizer. Contact your local County Extension Service for info on how much/often you should be fertilizing. Here in the Central Valley it is 3-4 times per year. I do 4: early March, late April/May, July and September. I use both time-release in the spring and suppliment with liquid the rest of the year.

Unknown is a camellia.

Citrus definitely need some good fertilizer and perhaps extra iron and other micronutrients (such as zinc, manganese, boron, etc.). Find a good balanced fert with secondary micronutrients like Ironite Plus.

Here's an update on the Meyer. Depending on where I look on the tree, I'm either happy or concerned. The center and far right seem to be yellowing, but the top and far left have strong new growth. There are also blossoms and fruit EVERYWHERE on this tree. If I bring the top down a bit and remove all of the ripe fruits, I'm assuming that a significant amount of stress will be removed from this tree.

I just don't know what's happening in the center. Is curling is a sign of underwatering? Went out with the moisture meter and the soil is still moist in some spots, so will let it dry out. @CA Kate z9 Do you have a recommendation for liquid fertilizer? Hopefully I can find one that will work with all of these trees, since they're planted in such close proximity to each other.

If you have a specific branch that look bad: there might be something wrong with that branch and I'd cut it out with clean clippers and then clean the clipper with alcohol between each next cut.

I use a liquid fertilizer from Urban Farms - uffertilizers.com. I've been told you can get it cheaper from Amazon than from the Co. I haven't done that yet so can't say much about doing that. I know a lot of people on the Citrus Forum use Fish Emulsion.

The irrigation system will take you a while to figure out -- I've been there. But once it's set up properly, it will keep your plants alive and healthy.

Also, as plants get bigger, they need more emitters installed to cover a larger area. Some homeowners simply don't keep up with that task.

Can you locate the controls to your unit and find out what the schedule is? You could find the make and model online, and see how many gallons your plants are getting for the time scheduled.

Since the plants sound established, you should aim for deep, spaced out watering sessions.

It would be ideal to find a local consultant to take a look at your system and make adjustments. Perhaps you could find someone at your independent nursery -- an investment worth every penny. Hope the landlord agrees...

Or take a look at this home irrigation primer:

https://xtremehorticulture.blogspot.com/2017/06/home-irrigation-primer-help.html

And as the primer says: Remember there are two types of overwatering: watering too often and watering using too many minutes. It is far worse to overwater the first way than the second.

@JoJo (Nevada 9A) Thanks for that. I'm going to look around for the number. There are hose valves that turn the systems on and off, and most of the pieces are buried. I know there's 4 different valves around the total perimeter of the house, so it may be a less sophisticated system. I'll take a look though.

I did just find something else, which hopefully someone can give me input on.

I spoke to a friend of mine (who is a landscape architect) about these trees, and while she isn't a citrus expert, she told me to take a walk around the neighborhood and see how the other plants are doing.

I was headed to the store when I saw this massive redwood covered in lichen or some kind of fungus. When I headed back home to prune some of the funky branches off of the lemon tree, I noticed that those branches seemed to have that same looking fungus. The persimmon tree has it as well.

Is this lichen and might this be the cause of the issue? Is there a way to get rid of it that will keep the fruits/lemons safe to eat?

After the plants are watered, check how deep the water has reached. Is it 2-3 feet down? The landlord could have winged it, or set it too low to save water. You shouldn't have to water that often, if they are watered deeply (unless it's veg or shallow-rooted, non-native, non-Mediterranean perennials and annuals which need more frequent watering).

Regarding lichen, it's a sign of something wrong with the plant, e.g. an injury, stress due to under/overwatering, depleted soil. The lichen is not the cause -- it's a sign that the plant is struggling and is unable to fight it off.

Thanks to everyone for your comments. I just picked up some 12-10-10 Ironite Plus fertilizer to get some nutrients in this tree. I've never used this fertilizer before, but a few had recommended 12-10-10 or fertilizer with micronutrients.

Hopefully this will help remedy the situation. More leaves are getting "funkier" by the day.

Silica,

this is a kind of lichen that grows on trees in warm/hot climates -- not in temperate climates and rainforests. Check out the LSU ag extension site if you need more info.

"Lichens are a clue that something is wrong causing the plants to grow slowly and decline in health. This could be a combination of factors like plant competition, draught stress, root stress, overwatering, soil compaction, poor nutrition or improper pH. If you remove whatever is stressing your plants, the lichen will go away."

cmcgin202,

This the last time (I promise!) I will ask you to reconsider your watering practices. I see your problem as a watering issue. Fertilizing your plants when they are stressed will only make it worse. Trees use GALLONS of water per day.

Please check out your local agricultural extension -- they will have info on how many gallons you should use. You should aim for a DEEP watering once a week this time of year. It's hard to do with a hose but possible if you let it drip for a few hours.

Good luck!

JoJo, competition, draught stress, root stress, overwatering, soil compaction, poor nutrition or improper pH. Billions and billions and even more billions of trees show one or more of these symptoms, with or without lichens.

Silica, just read on it. Nothing wrong with a bit of education, even if this does not apply to your growing zone or experience. Thousands of different species, some using other plants as a substrate.

Just because you don't have them, doesn't mean they don't exist. Where are you located?

@Silica @JoJo (Nevada 9A) Thank you both for chiming in here!

As far as the watering issue, I know there is something awry, but I do not know if it's a lack of water. I gave this tree a HEFTY soak when I had posted this, and the soil feels moist around the dripline. It was dryer than the Sahara before this. I can't dig around too deep, because I know there's a gas line there somewhere.

Now for the issue of the irrigation system. This house is duplex split in half, and we have one side. There is one water valve which I am assuming "irrigates" the area where my trees are in the rear of the house, and may not be regulated. In the front of the house, there's an Orbit irrigation system, with a manual on/off valve at the top (this is currently turned off). however there's some sort of wiring that looks like it was originally hooked up to something. I have no idea what it was hooked up to, but the white wire runs into the wall of the house, and I can't determine what it is.

Sounds like I may have to speak to my landlord on this one first, but it seems that the soil is still moist. The Meyer is the only tree that I'm concerned about at the moment, as the leaves seem to look funny, although they're producing lots of fruit. Here are more photos if you care to see :)

Hello everyone! I need to resurrect this thread as there's been a development!

So, since I've last spoken to you all, I've made some great strides with the tree. I've eliminated "suckers", given the tree a trim, and the tree itself seems to have freed up some spots in the center to provide better airflow.

There are beautiful blossoms everywhere on the outside of the tree, and tons of little baby green lemons. About 4 weeks ago, I applied a very small (1/2 cup) of Ironite Plus 12:10:10 fertilizer to my entire garden area, which is about 150 sq ft.

There was a massive rainfall last week. and I haven't been paying much attention to the inside of the tree, as the outside seems to be doing well.

However, there seems to be either a fungal issue with the ripened lemons on the tree. I'm not sure what the cause of this is, but it seems to be effecting every yellow lemon on the tree currently. Also, it seems like some critter likes the taste of these moldy lemons, and I see that some have bites taken out of them, which hasn't been a problem since I've moved here.

Attached are some pictures. Any thoughts? I'm going to clear all of the troubled lemons from the tree today with gloves, then wipe my gloves down with rubbing alcohol.

This may be a helpful link:

http://ipm.ucanr.edu/PMG/C107/m107bpfruitdis.html

It looks like they were left on the tree too long. Also, rats eat lemon peels and if they take a bite out of the peel, the lemon will mold. It looks like the same mold you would get if you left fruit out on the counter for a long time.

I'm reviving this thread to continue documenting all of the great feedback that folks on this site have given me. Thank you!

I last fertilized this tree with a small amount of fertilizer in perhaps April. I used Ironite 12-10-10 to fertilize the tree.

Lately, I've been watering around once per week due to the draught, and I'm starting to wonder if those waters have been too frequent. I'm starting to see yellowing tips on my leaves. Is this is a sign of overwatering or lack or nutrients in the soil?

Thank you!