The Tropical Fruit Forum

Usually, we get lows around 40F (5C) in January/February that trigger bloom. Between beginning of February and the end of April the trees are in full bloom.  March is pretty warm here in Florida 70-80F (21-27C). When we get freezing temps after the trees are in bloom, it can trigger all male bloom and no fruit is set. California has a much more similar climate to where you are. I have not heard of them having issues with fruit development like they do with Mango. Most of the issue with mango development in cool weather is powdery mildew, I think. I have never seen powdery mildew on lychee. In any case, if it is just an issue of heat, you could always tent the tree after fruit set to increase warmth. First, however you must get the tree to bloom. If no one else on Madiera is getting bloom, that indicates a lack of sufficient chill. Sporadic bloom can sometimes be fixed with cultural practices, but no bloom at all is a different matter all together. I would highly encourage you to seek out the "tropical" varieties such as Khom from Thailand, San Yee Hong from China, or Amboina from Indonesia. Once you start getting bloom, you can worry about what the tree needs to bring that fruit to maturity. Here is a link to an abstract that talks about how the Thai varieties can bloom wih higher temperatures.

https://www.actahort.org/books/863/863_55.htm

It has been speculated by some very knowledgable people that the early fruiting lychees require less cold to induce bloom and the late fruiting lychees require more. You might get a second bloom on the early fruiting ones, but I doubt you would get that on the late fruiting kinds. Fruit development has never been an issue here in Florida. Maybe the California folks can weigh in on that aspect. I know they have a similar issue with mango to what you mentioned. I don't ever remember hearing that it was an issue with their lychees. I would tentatively recommend the early fruiting kinds. Talking with locals who have gotten fruit on their lychees would be very helpful--what variety and when it bloomed.

Two other things come to mind: Elderberry (which must be cooked, but seems to be all the rage right now) and muscadine grapes (they do even better if grafted on native Florida grape roots, but no one produces that combination for sale to my knowledge). Once again, if your jabo grows there, the muscadines will likely do fine.

My advice would be to use light pruning to stimulate growth durring the coldest part of the year. I would plant a minimum of 3 trees and starting about 4 weeks out from the week that averages coldest I would lightly prune the first tree. About a week later I would prune the second tree, and a week aftet that the third. That should give you almost a month long window to "get lucky." Chances are all the trees won't bloom, but if you can get one a year that would be great. You could also use the tarps you had mentioned for a month or two leading up to the prunung events.

As Brad mentioned, your chill period sounds a bit marginal. Low 40-45 F (4-8 C) is ideal. That being said, Lychee does vary in what temp induces bloom. There are some Thai varieties that would have a much better chance of blooming with the chill you mentioned Khom being the most well known. I don't think there is anything that will bloom if you don't have weather below 15C consistently.

Quote from: Galatians522 on October 06, 2023, 06:40:16 PM

Have either of you tested these to see if they are self fertile?

I can tell you this I have 3 vines that are flowering from the same batch of seeds.

#1 will not set fruit on its own and is redish in color, I have to hand pollinate.

#2 seems to set fruit on its own redish fruit with bright orange pulp, however not every flower sets it may need some cross pollination. Also fruit like 60% on average with pulp.

#3 Yellow fruit that sets abundance, seems like every flower sets. Pulp +90%.

Wow! That sounds like a real winner! Sounds like there is some purple in the parentage somewhere.

Have either of you tested these to see if they are self fertile?

I am collecting wild plums from the local area. Mostly, this is part of my search for a long lived/idealy adapted plum rootstock with low suckering. However, some may be worth cultivating in their own right--especially for jelley (similar to the cottage industry for Beach Plum in the north east). They appear to be mostly the Florida variant of P. umbellata (Flatwoods Plum) with introgresion from either P. angustifolia (Chickisaw Plum) or P. geniculata (Scrub Plum) based on the particular specimine. I have been able to observe one of tree for almost 30 years. It appears to be an Umbellata x Geniculata hybrid and has had 100% full bloom even in years with only about 40 hours of chill. I presume that it would still fruit even with much less than that. I have also observed P. serotina and believe this to be the southern end of its range as well. P. caroliniana is very common here but holds no interest for me since the fruit is not really edible.

Quote from: Galatians522 on October 02, 2023, 05:39:51 PM

As far as plums are concerned, you have a lot more options in California than we do in Florida. My favorite Florida Plum is Scarlet Beauty. It seems to be the best adapted to my part of the state. The best tasting plum I ever had was Gulf Ruby. However, it is susceptible to disease here even though it gets plenty of chill. I don't know what would do well in California, but Zagers have been breeding some amazing stone fruit for many years. I think that Mirabelle is a myrobalan (European) plum selection. I would imagine that other myrobalans or their hybrids might do well for you, too.

Thank you, as I mentioned earlier, I have about 20 bitter almond seedling trees growing wild all over my parcel that I hope to bud graft this fall. Gulf Ruby is definitely on the list now. If you know of any other plum varieties worth growing, I'd love to hear it!  Thanks.

I don't know if its available in California. Don't get stone fruit bud wood from Florida or anywhere in the South East--too much risk for disease. Gulf Ruby is not self fertile and needs a pollenator, by the way.

As far as plums are concerned, you have a lot more options in California than we do in Florida. My favorite Florida Plum is Scarlet Beauty. It seems to be the best adapted to my part of the state. The best tasting plum I ever had was Gulf Ruby. However, it is susceptible to disease here even though it gets plenty of chill. I don't know what would do well in California, but Zagers have been breeding some amazing stone fruit for many years. I think that Mirabelle is a myrobalan (European) plum selection. I would imagine that other myrobalans or their hybrids might do well for you, too.

I am only generally familiar with these systems, but here are a few observations from common agricultural knowledge. Clay is actually pretty fertile soil. It mainly lacks nitrogen. About 10% of the world's nitrogen is fixed from the atmosphere by lightning. Organic matter mineralizes back to nitrogen and other components through biological processes over time. For every 1% increase in soil orgnic matter content, nitrogen inputs can be reduced by 10% according to recommendations I have read from the University of Nebraska. Logically, building up organic matter will supply the missing ingredient in a clay soil. Organic matter also improves water retention and infiltration and can absorb harmful elements like aluminum (similar to how activated charcoal absorbs odors in your fridge). Shade also reduces transpiration. I think those factors account for most of the benefits in the system.

Those are very common in CRFG exchanges.

So I hear, it is not common in Florida.

Wow! This is very intsresting. Thanks for sharing.