The leaves are kind of daylily like, so yes its clumping. Tradescantia x andersoniana, ohiensis, and virginiana, Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination. I'm trying ohiensis this year. Depends how big your cells are? I don't like using those small cells for WS'ing, they dry out way too fast, I use those 5x7" inserts or the big 6 cell jumbos. If they are jumbos cells, go for 2-3 seeds per cell.

sweet kate is a really terrific plant,and does not appear invasive, but i must warn you that the other greenleaved tradescantias ARE ABSOLUTELY HORRIBLY INVASIVE.as lovely as their flowers can be, they spread viciously and they are very difficult to eradicate because of their tenacious root structure (as opposed to an easy-to-pull-out,no-tools-required, invasive plant like lysimachia ciliata). 18 yrs ago, when i was a new gardener and my motto was 'Have shovel, Will travel'(i dug up any flowers out there that were free), i made the mistake of bringing tradescantia into my gardens. 18 yrs later, i am still fighting it. however, if you have a wild area and you don't care if it takes over, or a contained area next to a driveway, in those situations it may be fine.

When the whole flower "spike" dies the stem will start to yellow, I cut the whole head off and put in a paper bag to finish drying. To get to seeds, hold the stem part of each flower, peel back the dead flower petals to the center. Seeds are 3 sided, kind of football shaped, and there should be 3 in each flower. Andrea

Tiny, about 1.5 mm Here is a link that might be useful: