I bought my seeds from Richters in Uxbridge. It reseeds every year. Have you tried winter sowing? I've done them that way and had no problem. Most catalogues also carry the seeds. Marg

Florabunda sells those seeds as do Urban Harvest. I grow these plants easily. they even sprout between my interlocking.

What are you doing that you have trouble growing these plants/ They should be fine in your zone. If you cast those seeds out now, it will still grow to full flower by summer.

My plants germinate from seeds casts about by the previous year's plants. I also amend it further with new seeds. All I do is to sprinkle (not cover) the seeds as it needs sunlight to germinate.

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