do your trees green up at all after being fertilized? or do they stay pale and yellowish the entire time?

pictures would help. get pictures of the whole trees, and then zoom in on the leaves, and pictures of the ground around the trees.

No, they don't green up. I swear, it's like I'm not putting fertilizer down at all. I've long suspected that's what the issue is. Maybe I'm applying it wrong?

I'll get some pictures up later today. Thanks for the response.

Sounds like you are doing the right things; I would surely add Sulfur and Calcium to clay soils. I am a fan of the Vigoro citrus fertilizer; I use it for my garden trees, but I put 1.5 to 2 times the recommended amount (I have Meyers and they are heavy feeders). Your soil pH is too high for citrus, especially lemons, you might try adding vinegar to your drip irrigation, or sulfuric acid. Citrus does best in 5.5 to 6.5 pH. I would give them a healthy dose of Ammonium Sulfate; and if that doesn't help you may have other soil problems like salt. BTW I hope you are not watering your trees with water from a water softener (SALT!)

Describe your drip line, how much water are your trees actually getting?

My drip line is a 10-foot soaker hose that wraps around the trees 2-3 times and is connected to a sprinkler system. I manually water it once a week or so at dusk.

If anything, I overwater. I can't imagine it doesn't get enough.

Here are pictures. I hope I wasn't exaggerating when I said they are "terrible" looking. I think they can get its lush green foliage back, but the lemon tree especially seems to be losing leaves a lot faster then it's growing them.

These were taken at 9 a.m. They are generally in the sun from 10 a.m. to 4:30 p.m. in the winter.

Orange tree
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Lemon tree
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Looks like lack of water and appears to be a magnesium deficiency in the leaves; a good dose of epsom salt will cure the Mg problem; but don't expect the old leaves to regain their color. Watch the new growth. The results of all your issues is the trees are sucking the nutrients out of the older leaves in an effort to make new ones.

I've seen a lot worse ;-)

So how much water are you giving them?
How long do the soaker hoses run? Three, four hours?
Do you have any idea how many gallons you're putting into the ground?

I think your issues can be corrected with water and nutrients.

Josh

I run the soaker hose for one hour a week on average. I really have no idea how much is going into the ground.

I have a young avocado tree that's standard size and quite a bit bigger (about 6 feet tall). It goes through the same water cycle as the smaller citrus, with a much faster soaker hose. It seems to be doing fine.

i would fertilize a little more frequent.

how quickly does the soil absorb the water? you may try watering about a foot or so further up the hill, and when you fertilize too.

what do you guys think about mounding up some dirt about a foot downhill of the tree, to create a mini dam to give the water some time to soak in, instead of flowing downhill.

I'm no expert on your climate, but if there was significant water entering the soil wouldn't you expect to see some green on the grass or some green weeds growing near the soak hose? Or have you used a weedkiller???

Indeed, water longer (or smarter, by building a mound as Houston suggests).
You could also cover your soaker hose and entire drip-line with bark mulch, which will
really help to keep the moisture in the soil and make watering much more efficient.

Secondly, as the others have said, fertilize the trees.

Josh

A water soaker for one hour is certainly not enough to give your tree a good drink. You would have to run it for at least 3 hours or more to get any water to reach at least a foot down.

I was a landscaper for years and many I know lost their trees to shallow soaking with these hoses along with a lack of fertilizer.

Can you dig a trench/moat beyond the tree line and make sure that trench catches lots of water now that it's to late to pull it up and mound it?

Mike

Thanks for the advice everyone. A little surprised about the water. I guess I've been overly careful due to it being a hard clay soil and wanted to make sure I didn't overwater.

So you think 3 hours a week in clay is sufficient, or would that not leave any time to dry out? Maybe 3 hours every 14 days?

Why not use a dowel to check how deep and how wet the soil is? We do this with potted trees, but I see no reason the same couldn't be done for in ground trees so that you can get important information about their environment.

Great suggestion, Susan.
Much less traumatic than shoveling down 8-inches....which is what I would have suggested.

Josh

Citrange noticed what I did, possible herbicide damage. Have you used a "Weed and Feed"? It will damage any broadleaf plant.

If not herbicide, then you have a water or soil problem.

Does your subsoil have small bits of limey stuff? And have you tested your water for pH? A pool test kit may help a lot. My water and any water from high calcium strata can easily be > pH 8, not good for many citrus and that goes double for trifoliate or most trifoliate hybrid rootstock. Do you know the rootstock? If not, check with the grower.

I would add a couple inches of good partly composted native mulch, out away from the trunk 6-8in, and extending another 30 in. If you have a soil problem, this will help a lot. If you do have an alkalinity problem, do not use hardwood bark. And do not add calcium until you have proven to have an acid soil. If you have an alkaline soil/water, then expect zinc, manganese, and iron to be unavailable in the soil, making foliar application essential. As Johnmerr suggests, magnesium may be missing and it can be added to the soil as Epsom salt, try 3/4 cup spread out. Don't put much on the original root ball, that will damage it. And water Epsom salt in good, not with a soaker hose. That goes for any chemical ferts except slow release.

With a heavy clay soil, native mulch and organic fertilizer can make a healthy crop of earthworms which will naturally get air into the root zone and help a lot.

Your soaker hose is too close to the crown of the tree. And a little upslope focus is needed. The mound/dam mentioned is good in that it will retain nutrients as well as water. You need to try to get the roots growing out, so water according. Mike's suggestion about deep watering is key.

First thing I'd do is mulch that entire drip-area with conifer bark....
and then I'd turn that water on to soak the soil.

Josh

No, I have never used a herbicide in the area. Can't be that.

I'm sure it's a watering/fertilizing issue. Just got to figure out exactly what. My neighborhood is full of beautiful citrus, no reason I can't have a couple, even if the soil isn't ideal.

Is your avocado close to your citrus? Avocados are very good competitors for food and water; citrus are poor competitors. As for Calcium, don't confuse it with pH issues; your soil is basic, so add Calcium Sulfate (Gypsum) dig it into the soil; it will improve the water takeup and provide some pH adjustment. If you had an acid soil (low pH), you would use Calcium Carbonate, giving the same effect while raising the pH.

The avocado is about 35-40 feet away---no competition.

Thanks again for your advice. I'm going to purchase a couple more larger citrus trees. Hope I can get all of these going in the right direction.

sandigodude,

The first thing I noticed from your pictures was the extremely steep angle of your planting area - what is that, at least a 30 degree slope?!! Then, couple that with the fact that you have very infrequent rains, plus have a clay underlayer that turns to something akin to brick in SoCal's dessert conditions - I definitely think watering issues are your main problem here! I can actually picture in my mind the minimal water you're giving each week just sheeting down that slope. And don't think that running the water longer will help, either - it'll just continue to flow downhill. Also, applying mulch (on that degree of slope) will be useless, since the water that seeps below the mulch will only sheet once it hits that dry clay layer.

I know this, since I too live on a hill (though mine is probably closer to only a 20 degree slope) and I have a clay soil as well! Only difference is, here in the Bay Area, we get a little more rain than you (and I was still getting the sheeting problem I mentioned using MY drip system!).

You mention that you have a neighbor that can grow citrus. Are they similarly situated on a steep incline/decline? How old are their trees? I don't think clay is the issue here (you can be certain that if you have clay, they have it too!). If theirs are more established/older trees on the same/similar grade yard, I suspect they were planted correctly to begin with. How do you do this?

If you look towards the end of the Sunset Western Gardening book, there's an illustration/instructions on planting on steep slopes. As a few people above have alluded, you'll want to create a horizontal/level terrace on which to plant each citrus tree (I would actually recommend digging up the ones you have in the ground now and start over). From looking at your pictures, you can either dig back into the hill or place soil on the down-slope side of the planting - just make sure it's big enough. I'd say a 4 ft. LEVEL/horizontal diameter should do. Also, don't forget to mound up the edges so as to create a basin that can hold the water, slow it down, and allow it to seep downwards into the roots (as opposed to down the slope!). If you're worried about the clay being too slow to drain water, when digging your level terrace, you can amend the clay with compost that's mounded just a bit higher than the clay underlayer, and this should help very well with any draining issues you might have.

Finally, you'll want to heavily mulch (at least a 2-3 inch layer) the entire basin you've created up to about 6-12 inches from the tree's trunk to additionally help hold water (this is what I've done for my trees). Remember, the key is that citrus like periodic deep watering (and they obtain water/nutrients from the first 18 inches of soil), so you'll have to guage how much that is based on your local environment (I previously watered my new trees 2x/week at 5 gal/watering for the first year, for example) - I like Susan's dowel idea!

Best of luck, and let us know how it goes!

Tim

Tim, the use of a soaker hose (beneath the mulch) should allow water to soak into the soil below the mulch layer.

Josh

I would otherwise agree, Josh. But based on my personal experience in the case where the slope is so very steep, I would first at least recommend correcting the slope issue, then do as you suggest.

Tim