[dmg]

Hi I would like to have an easy to maintain flower bed at the bottom of my allotment.
I would like to have ones that would self seed and like foxglove/lupin style flowers. My soil is quite heavy clay.
Could you nice people suggest some others that will give colour/attract beneficial insects for most of the year?

Thanks
dmg

[New shoot]

My plot is clay as well and I find all the following self seed quite happily.  I let them do as they will and pull them up if they are in the way  

Calendula or pot marigold (I've got saved seeds of these if you would like some.  pm me if yes)
Borage
Love in the Mist or Nigella
Poppies
Nasturtium - you are a fair bit further north than me, so you might have to gather up the seeds of these and store them overwinter    Easy to do as they are great big seeds  

All attract loads of bees and other insects and will give you colour from spring through to autumn.  

[mumofstig]

All of those above 
Plus Foxgloves will self seed, but it's easiest to start with a bought plant or 2 and then let them get on with it The plants usually last a few years before they die.

Lupins are perennial - you can start from seed and then plant out, after that just leave them to get on with it

[dmg]

Thanks for all the replies,
New shoot I have lots of french marigold seed that i intend to use as companion plants, would they self seed also?

dmg

[New shoot]

Hi dmg

French marigolds are half hardy annuals so they won't self seed.  You'll need to start them inside next spring and plant outside once all risk of frost has passed   

[Madame Cholet]

i've got loads of nigella pm me if you would like some.

[dmg]

Hi Madame Cholet,
I have just got a packet of them but thank you for the offer.