Two years ago, I got a Lucifer crocosmia. It was a nice big plant, and seemed to bloom happily. At the very end of the season, I noticed a few brown leaves, but didn't think much of it. The second year, the brown leaves came earlier, but still after most of the blooming was done. This year, the brown leaves started before the blooms, and the flowers were hit as well. By this time, there's barely anything left of the plant!
The only information I've found on crocosmia leaves going brown is to do with mites and thrips. I can't say I've noticed any significant insect activity on the plant, however. It gets plenty of sun and moisture, and the soil is well-drained and amended with compost. The surrounding plants are all quite healthy.
Any advice or ideas as to why this is happening? Should I just throw out the plant and get a new one and plant it in a different spot? Help!