Dahlia - a Must Have Geophyte in 2019

Decorative Dahlia at Hudson Gardens

If you could choose four different types of plants in your garden every year and promote them far and wide on how wonderful they are to grow, what plants would they be? That's not so difficult to do these days. Anyone viewing garden related social media sites often post plant photos and stories, I'm guilty of that myself! The more difficult decision would be choosing the plants to brag about.

Hold onto your trowel, the decision to promote different plants each year is also being done by the National Garden Bureau, a non-profit organization that encourages home gardening. Their promotional efforts began in 1920. Each year they select and announce a specific annual, perennial, vegetable and bulb to learn more about and try growing. Plus they sell stuff. Other organizations promote plants too, one of my favorites is Plant Select®, which I write about often in this blog.

The National Garden Bureau's four 2019 plants include annual snapdragon, perennial salvia numerosa, the vegetable pumpkin and to round out the fourth - dahlias. 

Internet photo from vienboraglass

What most gardeners collectively call bulbs also includes other categories – corms, tubers, rhizomes, and tuberous roots.

Here's a closer definition of bulbs. Some are grown as annuals or lifted each fall and stored over the winter. Others are perennial plants like lily of the valley. Many can be grown as houseplants. There are also fall planted bulbs that bloom in spring to summer, don't forget fall crocus that are planted in late summer. And summer bloomers that are planted in the spring after the final frost.

Bulbs are technically called geophytes which are herbaceous underground storage units for their seasonal growth cycle. All the nutrients the flowers require are stored neat and tidy in these small plant organs. Sort of like the small travel trailers being made today that have everything you need to live and sleep in twenty feet or less. Of course these lodging units move around above ground while bulbs are below terra firma spreading or stay put plant gems!

True bulbs like lilies, tulips, daffodils, garlic and onion consist of fleshy layers of leaves (called scales) with a small base of roots at the bottom (basal plate) that anchors the plant in the soil.

Corms like gladiolus, crocus, freesia, crocosmia and bananas (not grown here, but now you know they are corms) contain a solid mass of stem tissue and grow new (baby) bulbs from the main bulb (mother). They look similar to bulbs but are usually round in shape and slightly flattened, not pointed like a true bulb.

Tubers, the most well-known example in the culinary world – the potato forms roots and foliage from growth buds, known as eyes. Tubers are usually short, rounded and fat with no covering. Caladiums, poppy and Greek anemone, cyclamen, gloxinias and gloriosa lilies all grow from tubers.    

Rhizomes are thickened, branching underground stems that grow horizontally. Most grow along or slightly below the surface of the soil, sending stems above the ground. This group includes cannas, calla lilies, lilies of the valley, corydalis, wood anemone and iris.
 

Dug Up Iris Rhizome

Tuberous roots look like swollen tubers. New growth buds or eyes appear at the base of the stem during the growing season. These include daylilies, begonias, dahlias, clivia (houseplant too) and foxtail lilies.  

Bulbs truly have a wonderful life. They store up all their energy during a brief period of good weather then remain mostly dormant during harsh weather conditions. When the weather is favorable again they grow and bloom, we smile.

Read more about growing dahlias on these links:

The Colorado Dahlia Society They have two judged shows a year in the Denver area - August and September, check this site for locations and times.

Colorado Dahlia Society Facebook Page 

Articles on Growing Dahlias from the Colorado Dahlia Society

Planting Dahlia Tubers

If you lifted your dahlia tuberous roots last fall and are storing them over the winter, be sure to inspect them and any other stored bulbs for health. If any are moldy or too soft toss them in the compost bin and replace with new purchases this spring.