Mirabilis jalapa is not hardy, so you'll need to collect the seed and sow it next spring indoors and harden off the plants before putting them out in the garden next summer. You may find that your existing plants have produced a tuber, a bit like a small dahlia's. If you have some they can be kept and started into growth next spring too.

Hi Beattie.Ah the Mirabilis....my husband loves this plant.When i lived in London we grew this and they were beautiful....We only had one plant come up this year and hubby is waiting for it to drop its seed.I think i am going to buy more in different colours for next year,stripey ones also...