Seeds, tubers, cuttings, oh my! There are many ways to propagate garden plants, and understanding them can be both fascinating and a bit daunting. Plant propagation falls into two main categories: sexual and asexual reproduction.
Sexual reproduction involves the flowering part of the plant, where pollen (a male part) combines with the egg (a female part) to produce seeds. Once germinated, seeds develop, giving the original plant the possibility to reproduce.
Alternatively, plants can also reproduce asexually. This method involves creating clones of a parent plant. There are many ways to do this, including tubers, cuttings, runners, and bulbs. Tubers are enlarged, starchy parts of the plant where stored energy is held. Shorter day lengths often prompt “tuberization” in plants, as these underground stored energy reserves can be a critical adaptation in harsh weather or periods of dormancy. Tubers can also be a delicious, carbohydrate-rich food for humans and animals alike. Plants that have tubers are either stem tubers, such as ginger and potatoes, or root tubers, such as sweet potatoes and cassava.
Some plants can be propagated both sexually or asexually. For example, dahlias can reproduce by seed or with tubers, but the method you choose will yield different results. Asexual propagation results in plants with an identical genetic make-up. So, dahlias grown from tubers will have the same color and traits as the original plant. On the other hand, dahlias grown from seeds will be more diverse because of the greater genetic variety that seeds have. You might not even know what color the flowers will be until they appear!
There are currently 42 species of Dahlias displaying a wide range of colors!
Since tubers store more energy than seeds, dahlias grown from these energy-rich tubers likely be more vibrant earlier in life. Since they are tough to overwinter in the mountains, this is the recommended method. Whichever way that your dahlias are propagated (or any other flower with a tuber or bulb) you will want to snip off the flower once it has started to dull. This way, the plant will focus its energy into storing carbohydrates in tubers instead of growing seeds. This should result in the plants having a super store of energy to develop into blooming flowers in the next season!
The genetic diversity that sexual reproduction creates often makes plants more resilient to disease, and it can create exciting color or flavor variety in your garden. Seeds are more readily available in stores and are cost-effective. For gardeners seeking consistency, if you have found your dream dahlia or fruit variety, tubers or bulbs may be the best choice. Since asexual reproduction creates genetically identical plants, these will bloom fewer surprises.
Dahlia tuber dug up from soil before winter
One difference in how you might care for plants entails how you fertilize them. Annual plants go through their whole growing cycle in one season and then die off, and usually require less fertilizer since they are growing only in their optimal season. On the other hand, perennials and biannuals may require more fertilization as support for all of the energy that it takes to resurge in the spring. Most tuber plants are perennials that would benefit from consistent fertilization, while many annuals are started by seed.
Whether you are into the consistency of tubers or the variety of seeds (or both!), understanding plant propagation helps equip you to grow a garden that fits your needs. Check in with your local friendly garden centers for tips on the best growing conditions for your plant. Wishing you all a tuber-licious gardening season!
Gabi Watkins is the Lead Naturalist at Walking Mountains and an avid tuber consumer who hopes to also become an avid tuber propagator.