When to Japanese Maples Produce Seeds?

[DrTolhur]

This question can be taken in two ways, and I'm asking both ways: at what point in the tree's life and at what point in the year.

1) At what age/level of maturity do Japanese maple trees typically start producing seeds. I assume there's some kind of base level of size they need to be able to put that kind of energy into seeding. I've attached a picture of one I have in my yard. There are others around my neighbourhood that have seeds by now, but this doesn't. And there weren't any on the ground around it in spring (we just moved in), so I don't think it's producing yet. I have no idea how old it is or what variety, but the base of the trunk is around 1" thick, and the total height is probably around 4.5 - 5 feet.

2) There are many maples around my neighbourhood (in both variety and number), and some have already dropped seeds, but I've heard that Japanese maples don't drop seeds until well into autumn. So I'm wondering if all Japanese maples drop their seeds at the same time, or is there much variation even within acer palmatum with this timing?

 

[leatherback]

I feel it might be dependent on variety & how it was produced.

I have some 3 year old grafted arakawa's here that have flowered last year and this year. I have some deshojo that were 10 years post-grafting when I got them, they never flowered in the 4 years I have them.

 

[Mikecheck123]

JMs can produce seeds when they're still really small, I'd say as early as their third year.

But I think all of them don't produce viable seeds until fall. They may or may not fall off.

Here in the Bay Area, where there isn't a lot of increment weather and snow, the seeds often remain on the tree all throughout the winter. You can just pluck em off in Feb/Mar. by the handfuls and they'll germinate just fine.

Peter Chan has a good video showing how he collects them off the trees in October and plants them in the fall.

 

[Shibui]

Grafted tree is from already mature wood so they will flower in just a few years depending on conditions and growth rates.
Seedlings can take longer to reach maturity but still only 3-5 years in reasonable conditions.

That one in the garden appears to be grafted. I can see a suspicious lump on the trunk and seedlings rarely have the orange summer leaves.

All Japanese maples are essentially the same species so all have similar reproduction cycles. Flower in spring, seeds mature over summer, ripe when the leaves drop then the seeds also fall through winter and begin growing when weather warms up in spring.
If JM are dropping seed in summer it probably means the seed was infertile or trees are under stress and cannot maintain the full load of seed. They can drop some so that the remainder can be viable.

 

[AlainK]

2) There are many maples around my neighbourhood (in both variety and number), and some have already dropped seeds, but I've heard that Japanese maples don't drop seeds until well into autumn. So I'm wondering if all Japanese maples drop their seeds at the same time, or is there much variation even within acer palmatum with this timing?

I first collected seeds after leaf fall. But many of them were gone because of the Autumn winds, and those I collected had a poor rate of germination.

Now, I collect "Acer palmatum & cvs" seeds when the wings of the samaras are brown, and the seed itself just begins to turn brown. I then let them dry for a couple of days, put them in the fridge in a plastic or paper bag, dry.

Then when the leaves of the maples outside have dropped, either I put them in plastic bags, humidifed but not soaked, or I just plant them outside in grow containers. Either way, since I've done it that way my problem is "culling" or not "culling" ? I have so many, I just don't know what to do with them. It's a pity most of you live so far away.

For those in Europe, I can send you some for the price of the postage, say some chocolates or a nice postcard or a (good) beer if ever I come visiting



I already repotted a couple of dozen of various A.p. seeds, and my small garden is getting jammed

 

[Forsoothe!]

Early summer Maple seeds that are shed are surplus to the tree and are not mature. While the early summer Maple seeds being shed seem like wasted effort, it is a sign that more seeds were fertilized than the tree can support. They do not have seeds every year in Michigan, I speculate because fertilizing in any given year may have been unsuccessful. For example, it may rain hard just when the pollen crop is at peak. I have seen Honeylocust, Maple, Beech, Linden, Birch, Elm and other species have more than one year in a row with zero seeds. Of course, by the time I'm collecting, mostly in autumn, I can't remember what the spring conditions were like, so in the end there are likely to be other factors involved, too.

Whatever else is true, fertility of a batch varies wildly from year-to-year, species by species, so collect and sow a lot more than you want.

 

[AlainK]

They do not have seeds every year

fertility of a batch varies wildly from year-to-year, species by species

True.
Very good observation, same opinion.