I have a lily patch that is on a southern exposure with plenty of sun, every other day drip irrigation, and lots of space for air circulation. I have one set of five bulbs of an asiatic variety where one stem has redish leaves, progressing from the bottom of the plant to the top. The leaves for all other purposes seem healthy. No curl, wilt, or drying. I have plucked one, and connot find any mites, etc. Any ideas? Some of the neighboring stalks have some of the same redness at the edge of the leaves on the top as well.