Understanding Where a Dahlia Comes From
Dahlias are native to Central America and can be found in Mexico and Guatemala. They were brought to Europe in the 1800’s and most were open centered collerettes. Gardeners quickly learned these plants hybridize easily and they now come in every shape and color, from mini, Pom Pom, waterlily, decorative, cactus, peony and more. In Europe you may hear them referred to as Georgina’s , but that was a naming error and the flower is truest named for botanist Andreas Dahl.
A good point of discussion to consider is where Dahlias are native so we can under some of the hype about too much rain and rotting tubers. These plants grow wild in the inland area away from the tropical and away from the hot arid deserts. They are found in the plains and mountains that are the backbone of the Central American peninsula. They like moist, temperate climates (sounds like our climate) and can extend into some of the drier moderately arid Central American habitat.
Biology lesson here- Dahlias require deep watering and are pretty heavy feeders. For a plant to have those survival needs, we can infer they must live somewhere naturally in soil that isn’t necessarily rich but has good access to water. It may be fair to conclude that these tubers can tolerate sitting in some water then.
Here is the caveat: Tubers growing wild are not dug and divided. So, they have established roots into the soil and the outer tubers can shield the inner tubers from too much dampness. A divided tuber does not have any of the small or large roots to help it if the soil is too soggy.
To over come this we either, dig and replant in the fall and the plant develops some roots before the soil temps dip low enough to put it in hibernation OR we plant in the spring when the soil temperature is warm enough to cause the chemical changes in the tuber that promote growth.
It is my humble opinion that temperature and waking a tuber is more crucial to tuber growth than getting wet. It doesn’t make sense in the native landscape that tubers can’t tolerate rain. They are native to moist temperate locations which likely would get spring rains.
