All bulbs do best if you minimize the number of leaves you cut when you pick the flowers. When you cut, make sure you leave a short section of the leafy part of the stem to give the bulb a chance to make enough food to survive through the dormant period.
It is also important to leave the browning foliage on your bulbs until every leaf has died right down. Don’t be tempted to clear them up until every leaf is completely brown. This is the time when bulbs photosynthesise and create food, stored in the bulb to help next year’s flower. If you remove the leaves half way through this process, you’re less likely to have a flower the following year.
I don’t lift any of my bulbs in the garden; planted deeply and mulched with a generous blanket of mushroom compost I leave them in the ground to over-winter. If you’ve grown them in containers and you notice any small ‘bulblets’ these can be kept and planted into a separate pot, and will reach flowering size in a couple of years time.
Add a drop of bleach to the water to minimise the oniony smell or change the water regularly. They will look good for up to 2 weeks without rearranging.