When can I start planting these fab recommendations?

[stirling]

Hi everyone
Novice gardener alert
Last year I posted on this brilliant board about a hopeless dry heaped area of soil in my garden that's currently hosting weeds.

These were some of the recommended plants for the patch. Helenium, achilliea, grasses, perovskia...

When can I start to plant these wonders?
Thank you

March, soil should be warm (ish) when they go in.

You could have planted them last autumn!

Oh no! OK, I'll wait till March. Thank you!