In article , Suz
writes

I'm now having another look at seeds and want more like this. Totally easy
to grow, the sort you can't kill. Don't care if they spread like wildfire -
so much the better. I like cottage style, with really soft pink blue and
white, and lots of soft green. Is there anything like nasturtiums, but not
bright yellow or orange?

Any suggestions of idiot proof seeds?

Lots of composites are pretty simple to grow - e.g. Pot Marigolds
(Calendula officinalis), Cornflowers (Centaurea cyanus), Cosmos (Cosmos
bipinnatus).

Among the mallows, rose mallow (Lavatera trimestris) and annual malope
(Malope trifida) are easy. So is Lavatera mauritanica, but it's arguable
whether it's worth growing. Common Mallow (Malva sylvestris) isn't too
hard either.

Honesty (Lunaria annua) is another easy plant.

I find evening primroses (Oenothera biennis agg) seed themselves
readily. So do Welsh poppies (Meconopsis cambrica), but they're
difficult to introduce in the first place.

Kenilworth Ivy (Cymbalaria muralis) is another self seeder (I find it to
be rather a weed), but it does have a mounding habit not dissimilar to
nasturtiums, and has pale blue flowers. I don't know how easy it is to
establish in the first place.
--
Stewart Robert Hinsley