What hardy edibles look pretty, are perennial and can go straight in the ground?

[PlayOnWurtz]

Sounds like the start of a bad joke! I planted some herbs in last year and ironically the only ones to survive are the parsley sage rosemary and thyme which has left the rest of the patch very bare.

What's inexpensive that's edible and pretty and will fill the gaps?

Mint will take over the entire garden fill a gap.

You say that. I managed to kill ours off somehow!

You managed to kill mint!?
I have a pretty, variegated oregano that has, just, survived the winter.
Chives die back over winter but have sprouted forth again in the last few weeks.

It was a chocolate peppermint but yes. I killed it

Chocolate mint does die back in the winter.

Oregano is pretty indestructible. Chives & garlic chives are both fantastic and flower at different times of the year. I have over 28 types of mint, all in pots but will be going into the ground still in pots at some point this year - Apple mint and Moroccan mint are two of my faves. Plus also Lemon Balm - again this needs to go in a pot in the ground. I have also now got Lime Balm which will also have a spot in my garden somewhere.
Other herby faves are Lemon Verbena, flat leaf parsley and a bit later in the year you can pop some Basil and Coriander in.

You can just rock up to a garden centre and buy some herbs and bung them in - the only ones that will sulk are basil and coriander at this time of year. So give it 6 weeks and they will be good [but are annuals so will die off later in the year].

Other faves that are pretty robust, are creeping thyme, sweet woodruff which will cover any bare ground in a year or two.

Sorrel, blackcurrant sage (looks different to regular sage), day lilles (Hemerocallis - flowers are edible in salads), chives / other perennial alliums.

Personally I'd give mint and lemon balm a wide berth unless you want to be pulling them out forever.

Fennel is very pretty, it comes in green and bronze foliage. I plant it in the flower bed, its lovely, tall and frothy.

Rhubarb , just not a herb....:)
All my mints are coming back from the winter respite - I have chocolate mint, and ginger mint.as well as what I was told was 'red' mint - very strong. All in pots though.
I was given pineapple sage last year - a tiny cutting , which as it was little I kept in the greenhouse, but that is doing well too.

Husbands

Lovage - it does take up a bit of room as it grows quite tall, but it has a very savoury flavour like a cross between celery & parsley. I also like to grow sorrel.

I buy thyme plants from the supermarket, harden them off split into little bits & plant as I like a lot of thyme plants.

Lemon verbena is glorious: lemon balm is a weed & seeds itself everywhere.

perpetual onions
sorrel
rhubarb
berry bushes