Why Drought-Tough Plants Die in Rainfall
With so many people trying to be good citizens and adjust their gardening habits to conserve water, we often get asked about why drought-tolerant plants die in periods of heavy, lengthy rainfall, especially when combined with cold temperatures.
Not that it isn’t obvious: you understand that drought-tolerant plants prefer to be on the dry side and that when we get more rain than they prefer, they are going to react negatively.
No, the questions that we get are more curious about the specifics of plant growth and development, and about how to handle the issue in the face of climate change.
As our viewers recognize, the question is actually pretty nuanced, which is why even though you know the answer, you may not know exactly what to do about it, and there isn’t a one-size-fits-all response. I would say that if you’ve lost a specific drought-tolerant species of plant, replant with something different.
And in general, try to avoid non-native succulent species, unless you have the capacity to completely change the soil and topography of your landscape to recreate their native region as a microclimate in your own yard. Look to plants that are native to your area, and reach out to your local county Extension service.
On a similar topic, what causes perennials, herbs, and bulbs to rot, and is humidity a factor? These plants often spend winter entirely underground, so if we have an extra wet winter and the soil has a lot of clay, or for some other reason holds too much water, they will rot.
Also, yes, if we have periods of high humidity, these plants may crater and die, seemingly overnight. Fungal and other pathogens, whose spores are always at the ready, lie dormant until the environment is conducive for their growth, then they pounce, figuratively, of course.
And on the flip side, why do we lose plants in extended hot, dry conditions? This question allows me to dig back in my memory to Dr. Murray Milford’s introductory soil science class at Texas A&M, where I learned the term “permanent wilting point,” which is the point at which the soil is so dry that a plant will wilt and not be able to recover. As you might guess, this amount of soil moisture is different for every plant.