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Thorns on Orange Tree

Posted by az_pamperedchef 9AZ (My Page) on
Fri, May 4, 12 at 13:35

So I've been reading many posts throughout these forums, so much to learn! One point that has been made is that orange trees don't have thorns and if they do, the rootstock is taking over. Is that correct?

I have a navel orange tree, over 10 years old, it was planted in the ground when we bought the house. It's about 10' tall and over the years has given me some oranges not many, but all incredibly sweet. Last year there was an abundance of oranges, but all shriveled and dry inside. I attribute it to lack of water as we were having watering issues.

Now this year, I've been diligent in fertilizing and watering it (along with my 5 other citrus trees thanks to this forum!) and it has set quite a few fruits. However, there are about 3 branches in this tree that have LARGE thorns on them. Is my tree doomed? Do I remove those branches or leave them alone? I don't want to lose my beautiful, well established tree!

What do you experts recommend?


Follow-Up Postings:

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RE: Thorns on Orange Tree

Not exactly, chef. Most orange trees do not have thorns, or if they do, they tend to be very small and sparse. However, what you're describing sounds like these shoots may be emanating from below the graft and are indeed coming from the rootstock. Without photos we can't really be sure. Please look at where the branches are emanating from. If it from below the graft line on the trunk, trim them away close to the trunk. Or, if they're coming from the ground as suckers, same thing - trim them under the soil level. Not doomed, just prune away. Rootstocks tend to be very vigorous and hardy - that's the whole idea around grafting to rootstocks :-)

Patty S.


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RE: Thorns on Orange Tree

i'm not away of any navels that have thorns. most likely suckers from the base of the tree. cut them off.


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RE: Thorns on Orange Tree

Houston,

I don't think he said it was a navel; and most sweet oranges, including navels, if they have been grown from seed and not grafted, will have thorns.

At any rate, we here who offer free advice based on our limited experience, can always give better advice if we have pictures to work with.


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RE: Thorns on Orange Tree

Compare the leaves on the thorny branches to the good fruiting ones. Including the edge and tip shapes, vein patterns, and petiole (stem). The texture of the edges too. Some differences in lower and upper branches are normal.

If you do not see differences then consider the following
(confusing) stuff.

John mentions seedlings. Most seedling orange are not exceptionally sweet. But that doesn't mean it cannot be. But you can bet they will be very thorny when young, with much smaller thorns on the higher (fruiting) branches.

I have seen several trees put out thorny limbs from a mature non-seedling. This often after neglect (not enough water last year?) has been remedied. I had a cutting tree that was bad about that. I have also seen several trees kept too long in a pot do this. I have not seen this in navels, but I only have one navel.

Try to locate the point it was grafted. That may not be easy on an old budded tree. If these limbs are below that point, they are rootstock suckers and must be removed. Rarely do commercial growers graft four or five inches above the root crown. (Amateurs do it all the time but the commercials are about a thousand times more abundant.) So a limb from eight inches above ground is likely not from the rootstock.

Larry


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RE: Thorns on Orange Tree

Thank you everyone for your responses. I took pictures, but I'm not certain they are helpful. It appears there is a "mass" of trunk in the center with other limbs coming from around it:
Photobucket

The limbs that are coming around it may be rootstock, I'm just not sure. This is a photo as they progress up.
Photobucket

Photobucket

This is some of the thorns, the photo isn't very clear:
Photobucket

Photobucket

What do you think?


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RE: Thorns on Orange Tree

The 3 branches with large thorns are almost certain to be rootstock with inedible fruit. Cut them off or they will take over the whole tree.


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Bad information

"Most seedling orange are not exceptionally sweet."

Most seedling oranges have fruit identical to the tree it came from.

Nucellar Embryony

Apomixis - development of an embryo without the fusion of male and female gametes.
Polyembryony - occurrence of more than one embryo in a seed.
Nucellar embryony - embryos form from nucellar tissue.
Nucellar embryony in citrus means that most embryos are vegetative not zygotic.

They are produced from nucellar tissue and are therefore clones of the mother tree.

Here is a link that might be useful: Hort 403


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RE: Thorns on Orange Tree

The entire tree looks as if it is made of suckers. That is a strange looking trunk system. Can you tell if they are all connected at the base or do they appear to each come from under the soil. It might be hard to tell cause they all look so close.


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RE: Thorns on Orange Tree

The tree appears to have had a pretty severe winter kill in its past that killed most/all of the top growth. It is a somewhat common event in Arizona on backyard trees that haven't been protected during the occasional winter cold snap. Limes and lemons are more prone to it than oranges though. The multiple stocks coming up from the root crown around what is left of the original trunk is the telltale.

I can't tell exactly from the pictures whether there are two types of leaves & branches. The good news is that there are no trifoliate leaves, which eliminates most of the common nursery rootstocks. The tree has a chance of being a seedling or cutting with no graft. Cuttings and especially seedling sweet/navel orange trees have a tendency towards thorniness. It could also be grafted on sour orange rootstock which also has a tendency towards thorniness.

Look at the leaves on the different branches to see if you can detect a difference between leaves of different branches. The petiole(stem) of the leave is usually indicative of the type. Sour orange leaves look quite a bit like sweet orange leaves, but there should be enough difference to make a comparison (if it is a grafted tree). One other telltale is that sour orange leaves are generally darker green than about any other citrus, especially in Arizona soil.

If you determine that there are rootstock suckers in the tree, especially if the entire tree is rootstock, it is worth considering grafting other varieties onto the suckers rather than just removing them. A tree like that could take a few grafts and be producing fruit in a year and a half, much faster than starting a new tree in the ground.


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RE: Thorns on Orange Tree

Blazeaglory, I cannot tell if the lower branches are connected at the base or come from under the soil!

Bada_Bing, I studied the leaves with my untrained eye and they appear to be all the same. I checked leaves from branches that had the large thorns and leaves from branches that had no thorns at all and did not detect a difference.

I'm afraid that the tree is rootstock. As I said before I didn't know anything of trees (citrus or otherwise) until I started reading the forum. I probably allowed these "suckers" to grow not knowing any better. :-( I need to read up on grafting as I know NOTHING about it at all!


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RE: Thorns on Orange Tree

Agree with bada bing and tantanman on this one. Looks like these are all suckers coming directly from the roots. Which would explain the large thorns. I don't see trifoliate leaves, so that would mean that either this is sour orange rootstock, or you had a seedling tree to start with (grown on its own roots), and your fruit will be the same as it was from the original trunk. Do you have any fruit on the tree right now? Was this the same situation last year and year before?? If so, then I would just water and fertilize, and enjoy your sweet oranges on rather wickedly thorned branches :- ) If your fruit this years turns out to be sour, you've got sour orange rootstock growing, and time to replace the tree.

Patty S.


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RE: Thorns on Orange Tree

from OP's second paragraph he said a "navel" was planted when they bought the house and it had produced sweet oranges:
"I have a navel orange tree, over 10 years old, it was planted in the ground when we bought the house. It's about 10' tall and over the years has given me some oranges not many, but all incredibly sweet."

next sentence suggests his tree started having problems last year:
"Last year there was an abundance of oranges, but all shriveled and dry inside. I attribute it to lack of water as we were having watering issues."

seems it was recently that there are 3 trunks with thorns on them: "However, there are about 3 branches, in this tree that have LARGE thorns on them."

i wouldnt worry about the old trunks/branches that had been producing sweet oranges for you, and just cut off any of the newer branches, since it just recently started having a few branches with thorns.

its my understanding that the original navel was a mutation off a different variety orange tree, and it was then grafted, and all navels are decendants of that original mutation. and since navels are seedless, there shouldn't be any navel trees grown from seeds.


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RE: Thorns on Orange Tree

Well, those 3 branches look pretty thick. Doubt they are from last year. I suspect they've been there a while, at least 3 or 4 years, so pampered would have to tell us if these are the same branches that produced the incredibly sweet oranges? The Parent Washington Navel orange tree's origin is somewhat uncertain, but it is believed to have come from a bud sport found in a Selecta orange tree in the early 1800s. Which was also named 'Bahia', and the original trees came from Argentina. Yes, technically every single Washington Navel orange tree (and actually the Cara Cara, which is again, a sport of the Parent Washington) can ALL trace their existence directly back to the two trees grown by Elizabeth Tibbets from Riverside, Calif. Very fascinating citrus history trivia :-) They are seedless, however, seedless actually means very, very few seeds - you can still get seeds in a navel orange, and in fact, there are clonal varieties that have come from the Parent Washington. Also, navel orange trees are comparably not very vigorous trees. They are sensitive to too much heat and also do not tolerate arid conditions, so you need to treat them with a little more tender loving care than some other orange trees.

Patty S.

Here is a link that might be useful: UC Riverside Citrus Variety Collection: Parent Washington Navel


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RE: Thorns on Orange Tree

Oh my! Brain overload! ;-) I can't be certain that those 3 branches produced sweet oranges before. As I mentioned before I didn't used to pay much attention to my trees or gardening prior to reading this forum. I guess it's true, ignorance is bliss!

I think the best thing is to see what happens this harvesting season and go from there, and keep an eye for suckers and remove them ASAP.

Thank you everyone,

Connie - aka AZ PamperedChef


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RE: Thorns on Orange Tree

Wow. That is good info on the Washington Navel. I love that UCR website! My grandfather is buried out there at the military cemetery and every time we go out there I love it because the cemetery is surrounded by groves and groves of orange trees! And many cool little nurseries.

Connie. Good idea. Keep and eye on your tree and see if you notice any difference in fruit between certain branches to see what the deal is. Keep us posted.


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RE: Thorns on Orange Tree

I just looked at my Mandaran orange tree and it is full of suckers. Never had them before and the tree is 25 years old. Looking at the leaves, they are different fron the fruiting part of the tree. The leaves are the same shape as the ones you have in the pictures. They are suckers. You should remove them.


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RE: Thorns on Orange Tree

I just joined this forum, and the thread I refer to is from last year, but hopefully I'll get a response!

I have been through two growing seasons in my house in St. Augustine, Fl. There are several citrus trees, which haven't been cared for for a while - before we bought the house, and since! I've done a little pruning, but today started seriously pruning a small orange tree which has not produced anything since we bought the house. It was completely covered with vines from the nearby fence (passion flower, bougainvillea and something else) which I cut to the ground in order to get rid of the vines last year, and pruned the vines radically again this year (in March). After removing the vines a year ago, the tree flourished but there was no fruit. There is still a lot of dead wood which we cleared out this afternoon, using a saw and removing large limbs. We left everything that turned green this year. There are blossoms and some fruit on the tree!

Then I went to work on a grapefruit which was HIGHLY productive this year, and the fruit was OK, not great. FULL of seeds and not very pretty, but they juiced well. The juice was a little too tangy, but not awful. It's a large tree, and as I pruned, I found fruit that's from two winters ago as well as some small fruit still from this past winter. I figured it couldn't be good to have two year old fruit, so starting cutting those branches. I noticed (ouch) some brutal thorns and came to this forum to read, suspecting those branches might be some kind of suckers from the root stock, which the forum confirmed.

After some more cutting, I realized that a major limb of the tree - maybe THE major limb - is covered with REALLY nasty thorns. If that's a limb that should come off, basically ALL the fruit remaining on the tree is from the root stock. If I cut it off, what then?

I'll gladly post some pix if someone is still out there and can advise me.

Thanks!


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RE: Thorns on Orange Tree

Two, almost three years ago, I planted some seeds from an orange I had bought at the store. I don't remember what kind of orange but I was curious to see if the seeds would grow. I wasn't expecting them to, but they did! I have long thorns on this tree, on all of the branches. I had no idea that orange trees had thorns. I live in the Northeast so I believe I have to keep the tree inside in a LARGE pot. I have some pictures. I have seen many posts on here that the thorns should be removed, but for me that would mean uprooting the whole tree system, and thus, not having a tree that is just a few years old. Would I be able to get fruit from this tree eventually? I do put it outside in warm months.


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RE: Thorns on Orange Tree

There is no reason to remove thorns, not sure why you would feel you need to do that, except to protect yourself. All seedling citrus trees have thorns, it's part of their protective mechanism to protect their tender young shoots from being eaten by animals. It can take seedling citrus trees many years to produce fruit. Limes will produce the quickest, at about 2 to 3 years. Orange may take several years longer to produce fruit.

Patty S.


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