Yes they can. At the end of summer lift the plant, clean the soil off it and place it somewhere dry where the folliage can wither and dry off. Then place the corms in a dry cool place to over winter. I pack mine with shreddied paper in boxes or large paper bags. This stops slugs getting to them. You can then start them off again next spring. The bulbs get bigger each year resulting in larger plants. I am sure some one will correct me if i have got it wrong.

I found you need to inspect the corms while in storage as vine weevil grubs love them. You can save the corms by scraping out any soft areas with a suitable implement (I use the handle of a teaspoon). Find the white C-shaped grubs with orange heads and squish them. I'm sure prevention is better than a cure, so if anyone suggests how to protect them it's valuable advice.

I agree with you Beattie. They can be the bain of your life.