Starting Mariposa Plum Seeds

I saved some of the seeds from the Mariposa plums I picked a couple of weekends ago to see if I could grow some Mariposa(ish) plum trees.

There is some conflicting information online (shocking) regarding Mariposa plum pollination, but it sounds like Mariposa plums either needs to be cross-pollinated by another Japanese plum tree (e.g. ‘Santa Rosa’) or is “partially self-fertile,” meaning that cross-pollination increases the yield, but isn’t strictly necessary. I don’t recall seeing any other types of plums in the area, so it’s possible that this Mariposa plum tree was self-pollinated, and thus, the seeds will produce fruit that are tree Mariposa, right?

Anyway, I’m starting some seeds and I’ll let you know in five years or so what kind of plums they produce (if any).

I found a youtube video online, and followed their instructions.

First, remove the seed from the pit:

I used a nutcracker to get them open. It took a good deal of force, but not a single seed was damaged in the process.
They’re like mini almonds

I put them in water to see if they would sink. Supposedly, if they sink they are viable, and if they float, they are not. I’m going to go ahead with all four, marking the one that floated, to test whether or not this is true.

You can see that three of the seeds sank, and one is floating

Fold seeds in a wet paper towel and place in a plastic bag:

The seed that floated is circled so we can see if it germinates

Now, I wait for roots, and then plant in soil!

I started these seeds on July 19th. Any guesses how long these will take to germinate (or whether they will germinate)?

5 thoughts on “Starting Mariposa Plum Seeds”

  1. I think you’re right about the floater – it won’t Sprout. And I’m going with 17 days to for the others to germinate.

  2. Not knowing anything about plum seeds, I’ll guess 3-4 weeks before you see a root.

    Can you eat plum seeds like almonds?

    1. I wouldn’t…. plum seeds (like other stone fruit) contain cyanide. Well, actually, they contain amygdalin which is converted to cyanide…details details… According to sources on the internet, a plum seed yields about 9mg of cyanide, so eating 20 or so plum seeds could be lethal.

      Although almonds are related to plums, the almonds that we eat are “sweet almonds,” which only contain trace amount of amygdalin/cyanide, as opposed to bitter almonds, which are more similar to the seeds of stone fruit.

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