Growing Mango trees in Southern California

[simon_grow]

I get lots of questions regarding how best to plant a Mango tree here in SoCal so I decided to start this thread. I should first qualify, or disqualify, myself as I am a relatively new mango grower and my trees are not the largest nor healthiest. I'm a typical lazy backyard gardener, often putting my daughters before my plants so my trees rarely get fertilizer these days and it's probably been over a year since I adjusted the pH of the rootzone with phosphoric acid and Sulfur.

A serious gardener will send out soil samples for analysis and this thread is not for the serious mango grower. This thread will be very general without any advanced techniques or equipment. This is the "Keep It Simple Stupid" technique using easy to find rootstock and some experience I've gained from mentors like Leo Manuel, Jim Neitzel and many others.

I've been killing mango trees for years so listen to my advice with a grain of salt but I am quite knowledgeable about the science of growing mango trees. First of all, when someone tells you what or how to do something, there should be a reason why. If that person is not giving an explanation why they do it that way or has some proof that the technique works, you may want to look elsewhere for advice.

I'll have to continue this subject in short segments as my kids keep me extremely busy.

Simon

[simon_grow]

Edited to include link
Florida rootstock trees don’t perform well for most gardeners
http://tropicalfruitforum.com/index.php?topic=15673.0

So, why not just plant a mango tree that you buy from the local nursery like you would any other fruit tree? There are several reasons. Firstly, Mangos are marginal here in SoCal and although they can withstand the cold in some counties of Southern California, they cannot easily grow unprotected in many other counties of SoCal. Mango growth is heavily influenced by climate and wether new growth is vegetative(leaves and shoots) or floral is primarily dependent on temperature. This holds true for Mangos in SoCal but not necessarily in warmer climates where age of previous flushes can also be of major significance. Aside from age of flushes and temperature, nutrition can aid in flowering promoting bigger or more flowers and can even help inhibit fruit drop.

Please see this article for in depth information on Mango flowering:
http://www.scielo.br/scielo.php?pid=S1677-04202007000400007&script=sci_arttext

Simon

[simon_grow]

The three major problems growing Mango trees here is the cold weather, diseases and high pH soils. For areas where Mango can grow unprotected outdoors, we have the issue of continual flowering caused by the cold weather. A new Mango grower is often attracted to the beautiful small potted mango trees in full bloom often holding some small fruit. What typically happens is the happy customer purchases this tree and tries to allow the small tree to mature the fruit. If the tree is large enough, the grower may actually be able to harvest a few fruit. The fruit quality is often mediocre at best and the tree becomes stunted from the efforts. The following year, the tree often grows very little and will often try to bloom again as cold weather approaches.

Because the tree was stressed holding fruit the first year, there is very little root and shoot growth the following year and the grower may actually experience what I like to call the "Magical Shrinking Tree" where instead of growing, the tree actually recedes with each passing year. In Warmer climates, a tree may simply veg out the following year in order to recover but in marginal climates, the cold weather is too strong a stimulus and the tree will flower again in the second, third, and following years. Flowering here in SoCal can take up to half a year or more.

Flowering can begin as early as October(sometimes earlier) and nightly low temperatures can still induce blooms as late as June and July as it did with some of my trees last year. I posted pictures somewhere but I forgot which thread. Foryounger trees, this often means we only get one long flowering cycle and only one vegetative flush, Ive experienced 0 growth flushes in a year for several trees, instead, it flowered again after a rest period.

Simon

[Samu]

I am book marking this tread!
Thanks a lot Simon...and happy to see you active again in this forum! 

[JF]

This is a worthy thread for anyone to bookmark especially SoCal mango growers. Thank you for the thread Simon!

[rliou]

Thanks simon for the great thread.  One thing to consider in southern california for mangos are rootstocks.  Some varieties grow ok on terpentine (VP, LZ and alphonso) but for other varieties it can yeild slow growth.  JF and simon have been experimenting with rootstocks.  We do notice that while on manilla the growth seems to be faster.  I am conducting an experiment on two julie trees.  One is on double rootstock (terpentine plus manilla) the other just turpentine.  I am puttingnthem at dame location next to each other to see if growth rate is indeed difference.  It is also conceivable that some of the faster growth could be related to actually having a tap root on manilla trees. Florida turpentine trees tend to not have tap roots

[simon_grow]

Thanks guys, it's good to be back. I will talk about rootstocks briefly but because Lavern Manilla is widely available here and it has been successful for so many of us here, I will simply recommend this rootstock as the number one choice for growers here. Rootstocks will be mentioned as part of the discussions on Temperature, diseases and pH.

The rliou, the more people experimenting and documenting, the better. I have a lot of new insight that I'll share in this thread that will hopefully allow us to grow more and better quality mangos here in SoCal.

Simon

[simon_grow]

Because weather has such a big influence on the growth of Mango trees here, we need to stop our current practice of picking out that little mango tree in full bloom or holding small fruit. I highly recommend using Lavern Manilla seedlings available at most Home Depot's and other garden centers as the number one choice when it comes to rootstocks for growing mango in SoCal. If you're trying to save money or plan on doing a lot of your own grafting, you will need a lot more starting material and I recommend planting lots of polyembryonic and Monoembryonic seeds from store bought mangos that you eat.

With Manilla or random seedlings as rootstock, plant the seed or seedlings in its permanent location in the warmest area of your yard. It is a good idea to plant in native soil that is loosened to a depth of at least 12-18 inches if possible. Deeper is better to some extent but in many yards across California, you will hit an extremely hard layer of rocks and clay just several inches below the topsoil.

It is extremely important that you do not over amend the planting hole with too much organic material as this will decompose over time and your tree will sink. Even when planting in 100% native soil that is loosened, I recommend planting the tree above grade. Because the soil was loosened, it will compact and the tree will drop over the years. This issue can be exacerbated by over amending with organics. If you backfilled the hole with 30% organic matter, plan on the tree dropping 30% plus additional drop from loosening native soil.

[simon_grow]

The planting hole should be square and not round. Amendments can be added on top of the soil and I highly recommend mulching the rhizosphere or drip zone. Im not going into detail in regards to planting, fertilizing or mulching, each of these subjects can take up a whole thread and many of these have in fact been discussed in previous threads so if you're looking for more information, try the search function above. I will provide links to threads of great significance where needed and I will include links to scholarly articles and research where pertinent.

Simon

[simon_grow]

When you plant your tree, it is very important to know the pH of your soil. You can send samples out for analysis but this may be too much trouble for the new mango grower. Instead, I recommend purchasing a simple pH test kit for soils or asking your local nursery if they can test or recommend a test kit to find out the pH of your soil. I've tested the pH of the soil and water at several locations all around San Diego and the majority of samples for soil and water were above 7.8.

Mangos grow well in the pH range of about 5.5-7.5. Outside of this range, it becomes difficult for the plant to uptake certain nutrients. Here in SoCal, we mostly have to worry about the pH of our soils being too high. Even if we brought down the pH of our soils with the use of Sulfur, Phosphoric acid/water drenches, the pH will generally drift back up and out of the acceptable range due in large part to a the buffering capacity of the soil itself and the pH raising affects of our local tapwater.

[simon_grow]

Once you have your tree planted, keep it watered but don't over do it. When a tree is first planted, it will need more frequent watering as the roots have not established yet but keep in mind that Mangos are regarded as drought tolerant and when the rootzone is kept constantly moist, there is little physiological need for the plant to send its roots out farther in search of more resources. I would hazard to guess that more rookie Mango growers have killed their mango trees from over watering rather than under watering. Over watering can decrease oxygen levels, promoting anaerobic conditions which can lead to root rot.

I want to re emphasize here that you should be planting seedlings that are not grafted. This means that you will either need to learn to graft or know someone that can do the grafting for you. This may seem like a lot of trouble to go through but if you want a healthy, large and productive tree, I highly recommend this route if you are looking for something other than Valencia Pride, Alphonso and a few other varieties that seem to perform ok on Florida/Turpentine rootstock.

If you do plant a pre grafted Florida/Turpentine rootstock tree, you will get annual blooms which will significantly slow down the overall growth of your tree. I also want to point out that not all Turpentine rootstock are bad performers here in SoCal. Leo Manuel has planted Turpentine seeds and used them with success.

Simon

[simon_grow]

For those of us that have grafted seedling trees or have purchased pre grafted trees, I often get the question of when do I prune off the blooms or flowers? I used to recommend that you prune off the panicles when the flowers or fruit are pea to marble size but I was wrong. It gets a lot more technical and the flowering article I linked to at the top of this thread explains the science in detail. In simple terms, you should prune off the panicles when the (average)temperatures are above about 65-66F. At around 63F, you will get partial blooms and at 59F, you will get full blooms.

If you read the article however, you will find out that temperature is not the only factor. The age of the current flush and other factors such as drought stress influence the amount of florigenic hormones that may tip the balance towards flowering or a vegetative flush. Other information I have read indicates that increased nitrogen levels in the leaves may tilt the balance more towards a vegetative flush but highly unscientific experiments performed by me and several other SoCal mango growers indicate that cold temperatures is a much stronger promoter of flowering and increasing Nitrogen levels in the leaves by foliar feeding with multiple applications of high Nitrogen fertilizer in Winter and Spring has negligible affect on swinging the balance towards a vegetative flush.

I must admit that that our attempts at foliar feeding with Nitrogen on hardened growth in cool weather was more than likely a futile attempt but we were desperate. For those that aren't aware, foliar feeding is much more productive in active states of growth when new growth is in the expansion phase. Please see this thread for more info on foliar feeding. http://tropicalfruitforum.com/index.php?topic=241.0

For a visual of how temperature affects flowering, please see page 23 of 29 from this article.  http://download937.mediafire.com/9gfg1c9as1ig/6ikqa9b0uxoz4el/Breakoutyonemoto.pdf

Simon

[behlgarden]

that was my conclusion too Simon. I want to wait until we are at night temps over 65, by that time, blooms are over and fruitlets are formed. Safely remove pennicles then. Otherwise you risk 2nd bloom and even 3rd and kill the graft.

[Eirlis]

Question - I have an in ground 3 year old LZ on turpentine rootstock that was damaged by my gardener's weed whacker and is now struggling. If I plant a manila seedling next to it and try an inarch graft, do you think it could recover? Or should I just start over entirely by grafting scions onto a LaVerne manila rootstock?

[simon_grow]

I would suggest starting a new tree.  The Turpentine rootstock tree probably has mature brown wood that is more difficult to graft. Also, the Turpentine rootstock has so many issues that I prefer to start new and use the Turpentine tree for scions only.

When you plant the Manilla seedling, do not graft it. Let it mature until it is fully established and fruiting size before topworking it with the LZ.

Simon

[simon_grow]

I recommend using LaVern Manilla seedlings as rootstocks because they are easily found and relatively uniform in regards to their performance around SoCal. We also have the option of using random seedlings as well and the benefit here is that you save a lot of money but you risk getting a sloweror faster growing tree compared to Lavern Manilla. The huge trees in Leo Manuels yard is proof that random seedlings do perform well here but some varieties may be more or less prone to diseases.

Here are some pictures of some seedlings that were direct seeded into the ground. Unfortunately, I was not even considering the ramifications of grafting such young seedlings with mature scionwood. This Venus grafted onto Kent seedling is in full bloom and is wasting its energy on this senseless flowering.


Here is a CAC/COC grafted onto another Kent seedling but this variety is currently not blooming even though it is only several inches away from the Venus and gets the same fertilizer, water and experiences the same weather. There are definitely scion/rootstock interactions at work here and probably the stage and maturity of the scion( before it was removed) has some influence on it vegging out.



For those planting random mango seeds into the ground, do not graft the tree with mature scions until it is fully established and at the size where it can actually bear fruit. These trees that I grafted too early will be stunted with annual blooms until it reaches the size that I should have grafted them at. I just want others to learn from my mistakes.

The blooms on my Venus have been on the tree for several months now, mango blooms on young trees take many months to form and removing them early will only trigger another bloom as I explained above. Even though the CAC/COC is not blooming now, it will very likely bloom this Winter and every year there after.

Because the bloom cycle takes so long, young seedlings will likely only get one or two growth flushes and because it expended much energy on blooms, the vegetative flushes will not be as strong.

A seedling that was not grafted will simply stall and swell buds in Winter and have a strong vegetative flush as soon as the weather warms. A seedling that was not grafted will likely have 2-3 vegetative flushes or more if fertilized properly.

With each set of new leaves a seedling veges out, it will increase the total surface area for photosynthesis. This extra amount of surface area for gathering energy needs to be multiplied by each day it receives sunlight and hopefully you can see that soon there will be a drastic difference in growth rate between the grafted and nongrafted seedling.

In essence, the grafted seedling will be growing at a linear rate where as the non grafted seedling should grow at more of a logorithmic rate.

Simon

[ScottR]

Wow, nice thread Simon,I haven't read all yet but what i have read is very useful information for Cal. growers

[simon_grow]

Thanks Scott, hopefully it will help people grow healthier more productive trees here.

Now that the temperatures are warming up, our plants and soil microbes will start showing activity again and this is a good time to re acidity the soil if you haven't already done so. For long term lowering of the pay of your soil, I recommend elemental Sulfur but this has a very slow pH lowering effect. In the meantime, you can use Iron Sulphate which is faster acting or you can also drench with water that has been pHed to 6-6.5.

I don't recommend using Aluminum sulfate due to the accumulation of Aluminum to toxic levels.

You really do need a soil test to determine the actual pH of your soil before you try to acidify but yellowing leaves are a good indication that your pH is drifting up.

For an organic way of decreasing pH, I recommend using cottonseed meal as it is acidic and will also provide nutrients to your plants. If using cottonseed meal, I recommend gently working it into the top of your soil so that the cottonseed meal won't clump together and get moldy when it gets wet.

Simon

[simon_grow]

For those Mango growers that don't want to plant seedling( not grafted with mature scions) trees and grow them to maturity before topworking, I have come up with a slightly less involved technique that has not been tested but should work in theory.

Again, to be safe, my number one recommendation is to plant Lavern Manilla Seedlings and plant them into the ground ungrafted. But, if you want to experiment or save a little money by planting random mango seeds, this technique may work and is much less labor intensive than top working a mature tree.

For this new technique that I recently came up with, you will need a seedling from a Polyembryonic variety that has a unique smell to the sap when you injure a leaf such as Lemon Zest or Sweet Tart. Plant your seedling into the ground or in a pot and take care of it like you normally would. You will need more than one sprout coming up from the seed and it's safer if you inspect the seed to make sure each seedling is coming up from a different segment of the seed. Because of this, it may be easier to sprout the seed in a clear plastic ziplock bag with a slightly moist paper towel to ensure you get at least two seedlings coming up from different segments of the seed.

You need at least two seedlings because there is a chance that one of the seedlings is zygotic. Grow up the seedlings until they are large enough to remove a scion or two. When the seedlings are large enough, break off a leaf and crush it in your hands. The sap from the clone should smell like the sap from the original actual parent Lemon Zest or Sweetheart, assuming you have these varieties and you know what the actual varieties sap smells like.

Once you find out which seedling is the clone, use its scion to graft onto your seedling or Lavern Manilla rootstock. By grafting seedling scions onto seedling rootstocks, the scion should not flower in its first winter but you will get the benefit of having a grafted tree with a named cultivar(sort of, because it's a clone seedling).

Simon

[simon_grow]

I'm just trying to compile all pertinent information into this thread and I'm lazy so I am copying a reply I posted on another thread. This reply has some info on why I feel Sweet Tart could potentially be a good rootstock for us to use in SoCal where I Strongly recommend planting seedlings that are not grafted and letting them reach fruiting size before allowing them to fruit or topworking them one they have established scaffold branches. Here's my previous reply:

Mono seeds will not grow true to seed whereas Polyembryonic seeds should have one zygotic seedling produced from selfing or from cross pollination and the rest of the seedlings should in theory be clones of the parent. This is basically the same as nucellar seedlings in Citrus.

Polyembryonic seedlings are especially important, in my personal opinion, because they are seedlings and lack the florigenic hormones that cause young, 1 foot grafted trees to flower in cold climates like mine.

Polyembryonic varieties are especially important to mango breeders as use for rootstocks because of their predictable behavior.  http://tropicalfruitforum.com/index.php?topic=20816.0

Thanks to Bsbullie for mentioning it in another thread, I never considered using the smell of the sap of crushed leaves(Zills technique) to determine the potential quality of seedlings. I used this technique and hypothesized that one can combine this technique with what we know about polyembrony in order to use the sap smell as a built in genetic marker, similar to how a researcher would insert the green flourescent protein as a marker that is clearly visible and identifiable. In our case, we would use our sense of smell to detect the clone but this only works for polyembryonic varieties most notably from the newer Zill selections that have a strong unmistakable sap smell such as Sweet Tart and Lemon Zest among others.

I confuse myself sometimes so what I'm trying to say is that we are lucky to have these strong sap smelling polyembryonic mango varieties like Sweet Tart because they have a built in clone indicator, the smell of their sap.

This year, I have plans to plant out many Sweet Tart seeds to test it as an alternative rootstock to Lavern Manilla for those trying to grow mango in colder marginal climates such as in SoCal. The Lavern Manilla grows great here but the fruit is horrible and not everyone knows how to graft. Additionally, the Lavern Manilla rootstock IS Polyembryonic but there are no Phenotypic markers allowing the nursery worker or tree purchaser to know with confidence that the tree is actually a clone. Without knowing that you have a clone, the predictability about the growth and fruiting behavior of that tree goes out the window.

I like Lemon Zest more than Sweet Tart but LZ has horrible issues with Powdery Mildew on specific rootstocks. The information I've found for Sweet Tart so far have indicated that it could be an excellent rootstock for marginal climates because of the following:
1) Vigor- its large size and fast growth will enable it to establish and reach fruiting size faster. In my area, mangos seem to grow at about 1/2 to 1/4 the rate compared to South Florida.
2) Polyembryonic- it has a built in Phenotypic marker that allows us to select the clone with confidence. Once the growth and fruiting attributes have been observed and documented, we will have a reliable tree with excellent tasting fruits that grows and fruits with predictability. Observations need to be made on seedling Sweet Tart trees and not ones that are already grafted onto other various rootstocks.
3) Disease resistance- observations made from trees grafted onto Florida rootstock as well as various other rootstocks including Lavern Manilla indicate that this variety is quite Disease resistant. I have not observed any issues with it regarding Anthracnose nor Powdery Mildew.
4) Production- this variety is one of the most productive varieties I have seen. Even small trees will set fruit and try to hold them to maturity. This is actually an issue for people growing mango in colder climates where I am recommending that we grow our trees to maturity( fruiting size) before allowing it to flower and fruit but this is a moot point because I am recommending that we grow seedlings which are not grafted and will thus likely not fruit until it reaches physical maturity.
5) Taste- recent taste evaluations at local mango tastings has ranked this variety at or near the top of polls.

Simon

[CBG35]

Quick question- what do you recommend if we already planted the grafted mangoes from Florida (on turpentine) in the ground.  They were planted this season and last season in early spring.  Varieties are LZ, cotton candy, Phoenix, fruit punch, mallika, PPK, ice cream.  We definitely noticed the propensity of these plants to flower.  Most flowered vigorously.  Last year we made the mistake of cutting of the flowering stalks and they flowered again.  This year, we left them on and are painstakingly removing the pea sized fruit one by one. The plants seem to be putting on vegetative growth, albeit slowly.  Will this continue?  If we are are okay with slow growth, can we keep the trees as They are?  Or should we buy manilla rootstocks and graft them all to make sure that we don't lose the trees altogether?  Then, keep those for scions in pots and do what you recommend starting with planted manilla rootstocks?

Thanks in advance for your mango tree growing wisdom!

[simon_grow]

If you already have the grafted trees, I would recommend treating them as you have been, taking care of them as best as you could. Some varieties do just fine on Florida rootstock and we don't know which of the new varieties does or doesn't do well on that rootstock yet. You may need to stake up the branches as they get droopy but you might as well work with what you have unless your goal is to grow large trees. I feel that if you are careful to monitor the pH of your soil and water, mulch your trees heavily and foliar with micronutrients, you can have Florida grafted trees growing well.

Fruit4me has many Florida grafted trees that are performing well although he is the only one I know of that has such a large collection of Florida grafted trees doing so well. His thick layer of mulch or his particular microclimate may have something to do with his success. Everyone else I contacted has trees in decline or their trees have already died. Some varieties like Sweet Tart, Valencia Pride, Alphonso and a few others grows fairly well on Florida rootstock.

I would just recommend that you plant seeds/seedlings/Lavern Manilla seedlings/ and especially Sweet Tart seeds in close proximity to the Florida trees in case the trees die. If they do die, you will already have a backup seedling that is potentially ready for grafting.

Growing mangos and gardening in general should be thought of as a dynamic process that is constantly changing and evolving. The gardener should have an open mind so that you are able to adapt to changes you observe in your trees. By having backups, you can be ready to save any particular variety if you notice parts of your tree dieing back.

Simply buying Manilla rootstock and grafting them will cause them to flower within a year or two although this may be your best option if you have a variety in decline and have no other rootstocks available. It's better to plant Manilla or whatever other seedlings and not graft them until they reach fruiting size.

I keep saying fruiting size and not giving specific dimensions or heights because each grower will have a different idea of what that ideal fruiting size is for them. One person may want a smaller tree and allowing it to fruit at a smaller size will take away some of that vigor and help to keep the tree small. Others may want hundreds of fruit in which case they should allow the trees to grow out very large before top working the main scaffold branches.

Simon

[Johnny Eat Fruit]

Very well said, Simon. I am letting my Manilla and Kent seedlings grow and develop in the ground and then I will graft top cultivars onto them. Our conditions here in So. Cal is quite different from Florida. Thanks for the advice and input from your learning experience as it is much appreciated.

Johnny

[CGameProgrammer]

My (alleged) Lemon Zest from Florida, which I bought about six months ago and is in the ground, has already set a couple dozen fruit but it is also growing new leaves from the base of those panicles, so it's not doing what some others report where trees fruit themselves to death. So it seems like a great performer.

My Coconut Cream, purchased at the same time from the same place (Plant O' Gram), flowered but did not set fruit and I haven't yet noticed any new leaves either, although I last checked a week ago.

[simon_grow]

My Florida grafted Lemon Zest is holding fruit and starting a new growth flush as well although I have to stake it up and it has major cracks in the trunk. Hopefully the fruit will be full sized instead of the nubbins I got last year. The panicles were heavily infected with Powdery Mildew and I plan on using baking soda to inhibit this fungus next year. Hopefully this works but I intend to re apply the baking soda mixture every once in a while, especially after a rain, in order to maintain a higher pH to make conditions hostile to sprouting spores.

I'm experiencing dieback on multiple branches on my LZ on Florida rootstock although one of my experimental Double Stone Grafted trees has died back even more severely and was on the brink of death before I sprayed it with Abound. It has since started bouncing back but I may pull it soon because my Sweet Tart on DSG is growing amazing without symptoms of Phomopsis. I'm starting to see why Mango breeders prefer Polyembryonic rootstock- because you can predict resistance, or lack there of, to diseases.

Simon