How well can the rust overwinter in the north?
There are many questions that fit this category. Is the alternate host necessary for northern overwintering? Can the urediniospores produced on the leaves remain infectious through the winter? Will mycelium survive inside parts of leaves which remain alive over the winter ? Do the different growth habits of daylilies affect overwintering of rust in the north? (Here is where a more accurate classification than the traditional dormant/sev/evergreen might prove important. Pat Henley has proposed two factors: continuous vs discontinuous growth, and deciduous vs nondeciduous. Two other factors that might be important are freeze tolerance and ability to grow at low temperatures.) A note of caution here: there are already reports in 2002 of northern growers overwintering rust on plants grown in greenhouses. It seems likely that the infection could escape to plants grown outdoors.
