Oh so drought tolerant!
Get a couple of days with highs in the 90s and our gardens will begin to tell us which plants are definitely drought tolerant. These days, we can all judge for ourselves. One plant in my garden that has not shown even a hint of a droopy leaf, is wild petunia (Ruellia humellis). And I must say, at this point, that makes it somewhat unique!
To illustrate how tough these are, these native wild petunias are planted in the desert known as the tree lawn, that space between a sidewalk and street that gets no additional hydration and lots of people and pet traffic. This is growing with western exposure too so that afternoon sun really adds the heat. Despite all that, they have just started blooming.
Wild petunia is a perennial flower growing 1' to 2' tall. I can attest to its ability to grow in dry soils. Mt. Cuba says it also grows fine in moister, richer soils. It blooms throughout the summer. In my experience, it is quite late in breaking dormancy. Please don't expect the bloom volume of annual petunias; this is not that but the pale lavender flowers are very pretty. Carolina petunia (Ruellia caroliniensis) is similar but. according to Mt. Cuba, needs moisture in sunnier locations. Even with all of this drought tolerance, these plants will need to be watered regularly to get established.
Wild petunia spreads by sending out very tame runners like this one. The best use of wild petunias I have seen is in the incredible cutting garden at Hillwood Museum.
The repeat of this short native plant draws you in and adds a certain charm along the path! Wild petunias are primarily available at native plant nurseries such as Watermark Woods. Please note many garden centers sell Mexican petunia (Ruellia simplex) which is an annual with willow like leaves and purple flowers. That petunia is native to Mexico and South America and has become invasive in parts of the U.S. Our native wild petunia is quite different but it can be confusing! If you are looking for this perennial, keep the latin name handy -- Ruellia humellis or Ruellia caroliniensis.
Happy Gardening!
