Stumbling forward, marking my progress so others might learn from my mistakes. I've now taken them out of the humidity dome entirely after noticing two problems.

Most troubling was the tips of the most distal new growth on the still extremely nascent true leaves was turning black. This was affecting the "blob" the new leaves were still differntiating from. At first it was isolated to a single plant and fearing a fungal infection I carefully parted and trimmed the blackened section.

It seems the tallest of the plants was simply the canary, so to speak, and another plant (second tallest) started showing symptoms a few days later. I suspect that the high humidity was preventing sufficient transpiration interfering with the young plants ability to deliver nutrients to the distal growth. Having taken them out of the humidity dome there seems to be some improvement 24 hours later.

Additionally, the cow pots I was growing them in seem to have started to feed some sort of mold that was thriving in the humid environment. There's clear white fuzz covering most of the pots on the outside which has me worried about what might be going on near the roots inside the pots.

The humidity chamber worked great for the first two weeks post germination, but I definitely left them in there too long and now I'm hoping I'm not hardening them off too quickly.

Without the protection of the dome I'm also moving them away from the window since it's a colder part of the house and instead moved them to a warmer, more central location with artificial lighting, specifically a pair of T5HO 24W bulbs at 6400K (2.2k lumens a piece) located 2" above the tallest protrusions of true leaves. We'll see how that goes.

24 hours after the move I'm noticing some troubling curling to the edge of one of the original post-germination leaves on one of the plants. Hoping that resolves as the shock of the humidity change fades.

I have previously failed to get Mimosa Hostilis seeds to germinate but tried again a week ago and used a slightly different approach;thus far I've had a much better outcome.

I scarified the seeds by getting some dry sand and placed it into a small shot glass, popped in 8 seeds and then using the pulps of my thumb and index finger picked up a pinch of sand with seed and repeatedly made a crumbling motion with firm pressure between the digits' pulps to get the sand grains to abrade the seeds' surface. The seeds did not look any different afterwards to the naked eye but they were popped into a small plastic opaque container with enough water to cover them and placed in a spot where the pot was exposed to sunlight. Within 12 hours 7 of the 8 seeds were swollen and less than 48 hours later 6 of 8 seeds had about a millimetre of initial tap-root visible.These were then planted in small pots containing cactus compost mixed with sand, vermiculite and a pinch of a proprietary preparation containing nitrogen-fixing bacteria (sold for aiding the growth of legumes) and this has been misted with water lightly daily. Checking on them today I have seen 4 have developed a pair of cotyledons and this is just 5 days after the process was started.

It would appear that the abrasive action of sand on the seed is sufficient to aid germination. Lets see how they do from here.

That's a brilliant abbrasion method Corpus. I'll definitely use that in the future, though with any luck my current girl will come out of shock from the temperature change and I won't be starting new seeds any time soon.

I've been down to one plant since my last post. I definitely kept them in high humidity for far too long. Once you see any sign of budding between the cotyledons it seems to be very important that transpiration be able to occur unabated. Otherwise the new growth will stagnate and eventually rot in place.

Current girl was doing well until I introduced a space heater to fight back the chill. Three sets of true leaves with a bud for set four rising, but as of today all the leaves stayed closed (introduced the space heater last night to bring overnight temps from about 10 C up to about 20 C). Fingers crossed she calms down and bounces back quickly once she has time to adjust.

Outside chance I've been overwatering her as well, but while I've been terrified of messing that up (or underwatering her when she's so young and fragile) her leaf coloration and shape still look good and this recent change is drastic, so I don't think this is root rot.

Out of curiosity, how early do they normally "turn woody"? The base of her stem has definitely transformed dramatically and I'm surprised she did it when she's only about 5 cm tall.

I don't have to much to add to this, on top of me being away from the page for a while now...

This last season I threw some old M. hostilis/tenuiflora seeds in a pot of very rich, tree soil.. Out of the six seeds that went in, there was only one that made it and KICKED ASS at that...

I will be doing alot more work come with this teacher this spring..

I am curious about cloning my one remaining healthy Mimosa. I had 2 at the end of summer but when i was moving them indoors i did not know the taproots had grown through the bottom of the pots and when I lifted the first it broke If I had my wits about me i would have attempted to clone cuttings from that one. The second was dug out carefully and then transplanted. She is doing great indoors under 6500K T5 bulbs.

I will probably wait until late spring to try when my baby goes back to the garden but if anyone has had some luck with it any tips would be appreciated.

They don't clone easily by cuttings unless you air layer. I read a thread about cloning by an experienced gardener trying the standard method of rooting, and he got around 10% strike rate. Read up on air layering, and give it a try in the Spring when you start active growth again. I'm doing the same.

Here is a link on the subject. airlayering Yeah let's try to remember to bump this thread by summer with results.

Just wanted to show my first flower of Mimosa Hostilis from a 1,5 year old (6 month in pot and 1 year in ground) started from seed. It's a poor one but much more is coming and I hope it will be magnificent (already is in my eyes ) soon.
So proud of my baby

It's a beauty!!

A nicer flower

Any advice on topping Mimosa? It is midsummer and was thinking it might be a good time to do it.

Just top it however feels right. This tree is very tough, you can chop most of it off and it'll grow back. Rain won't mess with it either after you top it. It rains like every day where I live and mimosa does fine summer and winter, rain or shine.

Just noticed that rhymes lol

Yep, i agree.

Perfect, this time I will try to clone the greenest tips I prune, leaving the woody parts and do a pictorial. The last clone attempt is thriving!!

How big/old I should grow my Mimosa plants until I can collect roots from them? I dont want them to die during collecting. They are now in 3.5l pot, 40cm tall and maybe 9 months old. I will airlayer one of them because it has grow to two nice equaly big pranches 0,5 cm from ground.
I am thinking about germinating rest of my seeds. There is 5 left. I germinate seeds by tropping them in boiling hot water straight from tea pot and let it cool down before I plant seeds in plastic pots.

I dunno really. I cut mine back to 7' tall early fall so I could bring her inside. I'd say let them grow a couple few years first. Mine is 3, she was stunted as a baby for the first year. A rodent dug out all my potted plant one day and she lived but the recovery was slow.

I have seen photos somewhere that depicted Mimosas in mound like situations where the lateral roots could spread and be harvested. Just be careful of the taproot. I was moving a potted one (sister to the runt) and the taproot had grown into the ground. It broke and it killed the tree I wonder how to contain the taproot when mounding where I am. She has to come inside in Winter.

The clone is looking sweet but I have not been able to replicate my first success.