spring flowering bulbs and summer flowering bulbs

I have a number of areas of my garden where spring and summer flowering bulbs share the same space. The one follows on from the other. To answere your second question, yes they will come back every year but with diminished vigour in a trough unless you help them. They should be fed with a weak liquid feed through the summer and a bit of bonemeal forked into the surface will not go amis. Then they will benefit form being emptied out and having the compost replaced every few years. I grow single species of bulbs in pots and 'try' to repot every year. Time often does not permit this but I make sure that they get repotted every second year. Do this at the end of the summer when the foliage has died away.

The problem is that the spring bulbs' leaves need to be left until they die back, to build the bulbs up for the following year, and this takes up to 2 months. In that time, they don't look very attractive. They do usually come back the next year if left, as they are hardy.

Summer bulbs are not usually hardy and need lifting and storing until the following year.

So the answer is - not a good idea, I'm afraid.