Did you know that it’s dangerous to plant Day Lilies in with Tiger Lilies – or more succinctly – to allow those wild Tiger Lilies to seed themselves among your tame and cultivated Day Lilies?
It’s not that they have an evil influence, or that they will breed with their higher-class cousins. No, it’s a simple but deadly disease called Botrytis Blight or Botrytis elliptica. While the disease attacks both wild and cultivated lilies, it rarely kills Tiger Lilies, whereas the results are much deadlier for cultivated Day Lilies.
For that reason, it is advised to grow Tiger Lilies in beds of their own, as far from Day Lilies as possible. Botrytis Blight is prolific in damp conditions, which explains why you see large swaths of Tiger Lilies growing on hillsides, where the soil dries quickly after rains.
If you see yellowing and brown-spotted leaves on any of your lilies, remove those leaves. If they continue or return, dig up the plant to determine if the root bulb is rotted. If it is, dig up not just every part of the plant, but the soil surrounding it. The disease lives in the leaves, contaminates the ground, and releases air-born spores the following spring. The sooner any diseased leaves are destroyed, the better your success with preventing loss.
Are Tiger Lilies worth it? Oh, yes. That’s my hillside you see, in front of my house. It’s a very steep hillside, much too dangerous to mow. My solution is to let it overgrow with groundcover and interplanted with Tiger Lilies, which are prolific propagators. Not only is my hillside no longer eroding, but it looks great all year long. The only downside is that it’s a bit too steep to easily remove the spent lilies, or the dried flower stalks. But, what a spectacular show in the middle of July, when few other flowers are blooming!