I've had some nice little yellow flowers in my border for a couple of years (I don't know what they're called but they've now seeded and I've gathered quite a few of them. Should I sow them now or store them till spring?
My wife keeps buying everlasting wallflower plants but they never 'everlast' over the winter period. They are now quite straggly and I'm going to cut the flower stems back as far as the leaves. Do I need to cut them down to the ground, cover them up, or take them into the greenhouse, to persuade them to come back next year?
we leave our wallflowers out all year, just cut them down to about three inches above the ground. They keep going!
Most of the stuff which self-seeds in my garden (e.g. nasturtiums) just grow where they fall. I'd scatter your yellow seeds now where you want them to flower, and let them get on with it as they would in the wild.
If the yellow plants seeded themselves then they should do it again.
Is it a perennial wallflower with purple flowers? If it is then you just take the flower spikes off. There's no need to anything else. BTW, they only last for about 3 or 4 years before giving up the ghost.