Why did my lobelias die?

They are (well, rather, were) trailing lobelia, and I did not plant them in hanging baskets but rather between two steps made of old railway sleepers which mark the boundary of our new patio which sits a bit lower than the rest of the garden. There is about the width of a sleeper between the two beams with soil and compost, where I sited the lobelias (and a few kitchen herbs too). One by one the plants just wilted and look rather dead now. I watered them twice daily while it was dry and in the last few days when we had quite a bit of rain I still watered them after sunset, just in case, but they still gave up.
Were the kitchen herbs the mistake? Should I have left the wee flowers on their own in there? (It's parsley, oregano, basil and chives.) I thought lobelia were half-hardy, we did not have any frosts anymore since I planted them out, although it was a bit on the chilly side for a couple of nights but I did not think that would cause such problems? The only two plants (out of the initial eight) that still look healthy are those closest to a corner were there is a bit of shelter from a neighbouring container - but there was not really any wind until yesterday either...

 

Its too cold for all that stuff to be outside.

 

Yes, I think that's the problem. Nights here are still quite cold, no frosts but only just above- try again in a couple of weeks!
My parsley is just germinating in a raised bed, and chives are fine but they are a well established clump.

 

Were they gradually hardened off first? If not, the sudden change could kill them. Even down here ours are in a covered cold frame and will not take the lights off for another week. You may have been a little hasty.

 

I blame the Garden suppliers they all sell 'soft plants' far too early. Unless you have a suitable storage for anything up to 3 weeeks, mid may certainly here in Wales, you may end up with compost material. New gardeners keen, and why not, to get their plants in are not often advised by the seller and go home with armfuls of plants and can be dissapointed. I was there quite a few years ago.

 

I believe you were right - however I managed to save 4 out of the 8 plants so considering the timing it is not too bad! Everything else I bought and planted is doing great - I am particularly fond of the Kilmarnock Willow I planted which looks truly amazing already! My wee bulbs and tubers are also poking through the soil now so things start to look up. (And yes, I am sure I planted EVERYTHING too early, but having to deal with a completely new flowerbed and wanting it to look colourful and nice as soon as poss, I could not resist!)
I would love to post a new pic of how everything looks now but last weekend hubby and a friend have ripped out the old fence to one side of the garden to erect a new one and now all the old fencing stuff is piled up in the middle of the garden and looks horrible - it is all half rotten posts and bars and boards (rather than panels as they are nowadays) mingled with wire mesh... Unfortunately they could not yet rip it all down as we had to get more materials in (and the post anchor drive-in tool had also been crushed after 8 posts already :D ), but hopefully at some point during the week it is all done and we can get a skip and get rid of all the garbage, making the garden look nice again!

 

I'm not sure if the railway sleepers had anything to do with your problem - a friend of mine lost a number of plants and he put it down to the residual oil/tar products in okl sleepers!