There were questions on another thread about growing porterweed.

My experience with reseeding porterweed is that by the time the weather gets hot enough for it to sprout, it will not have growing time enough to bloom before frost.

I put both red and blue porterweed seeds in soil in the greenhouse in late winter this year. I scraped some seeds out of the dry spikes, and put some pieces of the spike with seeds intact, just in case. Covered them lightly with soil with some of the spike pieces exposed. NO blue sprouted. I did not do any cold stratification, since these are tropical plants. The heartiest of the red plants are not yet showing signs of bloom spikes, but I am hopeful. A red porterweed from seed that I started last year never bloomed last year, lived through the winter with heavy mulch and is showing short spikes now so bloom is eminent.

The most successful carry over I've had, other than plants that manage to survive winter's cold in the ground, was a piece of blue porterweed that broke in the fall. I put the long sprout with spike intact in a vase to enjoy the blooms as long as possible. By the time the blooms were done, roots were forming. I transplanted it to a pot of soil and it thrived in the greenhouse. Planted in the garden when the soil warmed, it has bloomed since mid June.


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Without a greenhouse, I would experiment to see how long rooted cuttings would live in a vase of water on a bright windowsill, as well as potting cuttings.

Has anyone else had different experiences?

Nell