Helping out old lemon trees

Hi everyone,
We have just moved onto a small farm owned by non-farming folk; as a result the soil is in poor condition and trees have been neglected. But we are up for the challenge! There are a few old lemon trees on the west side of the property. I was out this morning removing all the dead branches and clearing weeds from around the trunks so I could cover the soil with some compost prior to planting up guilds around the bases. I'm thinking comfrey, yarrow and wild garlic to start with as I have those readily available. But I wanted to ask how best to bring the trees back to healthy fruit production - the lemons are a rough skin variety, 2 are yellow and 1 is orange but they are either diseased or lacking in certain minerals/nutrients. They taste good though. The trunks and branches have lichen on and ants are busy farming aphids on the leaves, so I plan on using coffee grounds at the base as a mulch and ant deterrent.

Hello Joe,

Yes, obviously the trees are under stress from neglect.

Although citrus can be trimmed to a variety of shapes, the best for old established trees is a wine glass shape to get air and light through to the centre.

I'd delay planting anything around them since the trees are already stressed and need to be rejuvenated first.

Following a good trim that includes removing any water stems, it will need a really good soak with water. Citrus are heavy feeders, so a good layer of compost and manure, blood and bone, lime, then mulch and water in.

Keep all the fertiliser and mulch away from the trunk, and extend the fertiliser/mulch out to the drip zone to cover all the feeder roots.

The insect attack is the result of an unhealthy tree. This can be remedied by spraying with White Oil (a simple mix of any cheap cooking oil, liquid dishwashing soap, and water). The WO will kill ALL insects, so it may be appropriate to use it only a few times until the aphids are gone - ladybugs can only do so much!

Regular watering and feeding throughout the year will reward with lots of really nice perfumed flowers and plump fruit.

Have fun!

Thank you so much for your helpful reply, I appreciate it. Hopefully I'll be able to follow up in a few months with some pics of our lemon trees in full recovery.
BTW, do you know what could be causing the discoloration/scale on the fruit skins?

Those trees will come back.  They need a healthy diet of good compost to bring life back to the soil, a thick layer of wood chip mulch over the compost, and consistent moisture (not on the leaves or branches, but across the breath of the root zone).  

Citrus trees are nitrogen pigs, but if you hit them with synthetic fertilizers, they tend to flush with too much new growth, which in turn tends to draw a lot of aphids and leaf-cutters.  A better strategy is to pee around the trees every day.  No need to mix it or dilute it --- just take a leak and watch the trees green up and start to throw off new growth.  If you don't want to go out there every time you have to take a pee, perhaps you could park a chicken tractor over that space for a couple of months and give the trees all the nitrogen they'll need for a year.

You don't really have to prune a citrus tree as much as just thin it out a bit from time to time, and shape it if it gets too leggy or heavy.

So . . . compost, mulch, water, pee . . . yup, that about covers it.

Joe Black wrote:BTW, do you know what could be causing the discoloration/scale on the fruit skins?

From the pics it appears the trees had uneven watering, could be a long period of dry followed by a sudden wet, this would cause the fruit to swell and burst, then heal with a scab.

The discolouration looks like powdery mildew. There's lots of treatments for that e.g.  soapy water, copper sulphate, neem oil, et al.

Oh yeah, I suggest you consider removing all the fruit and, say, 3/4 of the flowers next fruiting season to give the trees a chance to recover. The reward will be healthy, shiny leaves and good fruit. 🍋

🙂

Marco Banks wrote:So . . . compost, mulch, water, pee . . . yup, that about covers it.

Got it! Great advice, thank you. Will start peeing under the trees today

F Agricola wrote:Oh yeah, I suggest you consider removing all the fruit and, say, 3/4 of the flowers next fruiting season to give the trees a chance to recover. The reward will be healthy, shiny leaves and good fruit. 🍋

Yes I was wondering if that would help, so will remove all the fruit this week. Thanks!

I've been composting and peeing on my lemon trees under sound advice from you good people
I also harvested most of the lemons this morning (6 large buckets to be turned into juice, lemonade and Moroccan salted lemon).
I noticed what are obviously two industrial scale aphid farms right at the top of one of the trees. I've left them alone and will approach the issue via building the soil and the strength of the trees. Just thought a pic of the aphid farm might be of interest.
(I wanted to upload a small video too but it looks like that's not possible except via YouTube).

Aphids are always a reality with lemons.  Ants carry the baby aphids up to the new green growth and "farm" them.  The aphids suck on the new green leaves, and the ants suck the butts of the aphids to get sugars from them.  Gross, but true.

You can do a couple of things.  

1.  Blast them with the hose, knocking all those aphids off the leaves.  You need to do this every couple of days because ants are persistent.

2.  Plant a variety of other flowering plants around the base of your citrus trees that will attract lady bugs, praying mantis and other aphid eaters.  

3.  If you want to use an insecticide (some sort of organic or non-organic chemical treatment), I'd focus on the ants on the ground, not on spraying the leaves of your tree.  If you spray the tree, you'll wipe out the lady bugs who take up to 60 days to come back, whereas ants and aphids are back within 2 weeks.  It's better to dig around on the ground, rake back the mulch, and find the ant nests.  Then pour a bucket of water with very little insecticide in it directly on the ant colony.  I only do this in rare instances -- I don't want those poisons around where they continue to kill the beneficial insects.

Unlike many on this board, I'm not a chemical purist.  I don't use but a fraction of the chemicals I used to use --- maybe 5% --- but if I've got fire ants, I'm not going to co-exist with them.  My skin reacts horribly to fire ant bites.  But my orchard and garden is so healthy now, with so many beneficial insects, I don't have to spray anything.  Ants die with just a fraction of the chemical application rate that is recommended on the side of the bottle (malathion).  I'll use a single cap-full with a whole 5-gal bucket.  I'll pour it directly on the ant colony and that's it.  Then I'll cover that spot with clean mulch.

Lemon trees are tough suckers.  Once established, they don't take much care at all.  We get so many lemons we have to pick 300 or so every year and toss them into the compost, or they'll break the branches.  I can't give them away, there are so many.