When I saw these, my first snakeshead fritillaries growing in the long grass at the side of my 'lawn' (such as it is) I nearly took all my clothes off and ran round the garden screaming. I'd always grown these in pots (because, obviously they are must-have plants) but they're SUPPOSED to live in the meadow-like atmosphere of your lawn-outskirts and multiply with abandon to provide you with carpets of bliss every spring. With this in mind I planted some bulbs in September last year, very hurriedly and without much ceremony...just removing a clod of lawn, dumping the bulbs in and replacing the clod...I didn't even water them....I never, ever expected them to come up. Fritillaries seem to hold some sort of mysterious allure to me - their beautiful nodding, tessellated petals and wiry stems seem to whisper "I'm too beautiful for an ordinary mortal like TOI"
But hey....as with most things in life, I am wrong.
If you want to grow fritillaries order your bulbs well in advance and plant them in autumn for flowers the following spring. They will have their delicious moment pretty much right now and be over before you know it. Go next year to somewhere like Magdelen College in Oxford and have a look at them en-masse - it is heart-stopping. They come in every shade of purple, and white, but you see the chequered pattern better on the purple. Once they're over the stems grow much taller and they dry out to disperse the seed from those fat capsules, so don't even think of chopping them until the wind has done its dispersal job.