Planting the Season's Dahlias

June 21, 2021

All our dahlias are planted, and I can't wait to see those colorful, spiky flowers that bloom from midsummer right through the first frost.

Dahlia is a genus of bushy, tuberous, herbaceous perennial plants native to Mexico and Central America. They grow from small tubers - ours were saved and stored from the previous year. This season, I decided to plant our dahlias behind my large vegetable greenhouse where they can get full sun. There are many named dahlia varieties with flowers ranging from small to giant dinner plate size. Many of our dahlia tubers are from Floret, a family farm and floral design studio in the State of Washington. We also have some from Swan Island Dahlias in Oregon, a family owned business and the largest and leading dahlia grower in the United States. And, a selection from The Flower Hat, based in Bozeman, Montana.

Enjoy these photos.

: This area is located right behind my vegetable greenhouse. It was previously used for my grape crop, but I knew it would work excellently for the dahlias. It gets great sun, and dahlias grow more blooms with six to eight hours of direct sunlight. And because this spot is behind this large structure, it is also protected from strong winds.

: All these dahlias are frost-tender tuberous plants that can overwinter outdoors where the weather is mild. However, here in the Northeast, severe winter conditions can cause them to split and rot, so they must be pulled from the ground and stored away every fall. We store them in these crates and place them in the main greenhouse basem*nt during the cold months.

: Brian and Dawa dig all the holes for our dahlias. These are fairly shallow holes and about a foot apart.

: Brian checks that each hole is the proper depth. Each of the dahlias must be placed at least three-inches down beneath the surface. Dahlias thrive in rich, well-drained soil. The pH level should be 6.5 to 7.0, and slightly acidic. For heavier clay soil, add in sand, peat moss, or aged manure to lighten and loosen the soil texture for better drainage.

: Once the holes are dug, the area is also treated with a sprinkling of Osmocote – those small, round coated prills surrounding a core of nitrogen, phosphorus and potassium.

: Brian also drops some super triple phosphate – an enriched source of phosphorus which encourages good root growth and flower formation.

: Meanwhile, Ryan unstacks the dahlias and goes through each bag to decide where the tubers will be planted – keeping in mind their colors and height at maturity.

: Each bag contains a bit of last year’s soil and some vermiculite which can be added to the soil when the tuber is placed in the hole.

: The roots of dahlias are actually tubers. Similar to a potato, the tuber sends up a shoot that becomes the plant, which produces leaves and flowers.

: Ryan creates a marker as each dahlia is ready to go into the ground.

: Dahlia tubers look a lot like a bunch of brown carrots, and the little budding sprouts that end up as thick strong stems are called “eyes.” Pink “eyes” or a little bit of green growth are good signs of a healthy tuber.

: Dawa places the dahlia in the hole and backfills the hole with soil. The first leaves should poke through the surface in about one to two weeks.

: Once the dahlia is planted, Brian also sprinkles Epsom salt over the soil. Epsom salt will feed and nourish the growing dahlia bulbs and help increase the vibrancy of the flowers.

: I designed these stakes for my gardens and had them made from galvanized steel, which won’t rust. I use these stakes for my herbaceous peonies and also to hold up the dahlias.

: Dawa places a stake next to each planted tuber. Once the dahlia starts to grow, the stems will be secured to the stake to keep the heavy blooms from falling over. These tuberous plants have slender erect stems which are not always capable of supporting the larger flowers.

: All the markers are inserted deeply into the soil next to each variety. The area looks quite odd without any plants, but it won’t be long before they start to poke through the soil.

: Among the many, many dahlias we planted this year – this eye-catching cultivar, Dahlia ‘Castle Drive’. It has a soft blend of pink and yellow and is great in arrangements and gardens. This plant is also very attractive to bees and butterflies.

: ‘Myrtle’s Brandy’ is a red dahlia with white tips whose petals fold back towards the stems. It is an excellent cut flower variety.

: This is ‘Karma Corona’. The Karma series was developed for the cut flower market. This variety has strong stems and flowers that open with a blend of beautiful salmon, yellow, and bronze.

: ‘Maltby Pearl’ has soft, creamy pink petals edged with lavender and tipped with white. This unique color combination gives them an almost metallic effect.

: ‘Thomas Edison’ has huge and magnificent, deep purple blossoms. The fully double flowers up to eight inches wide and are borne atop strong, sturdy stems. Blooming from now until frost, this dahlia grows up to three to four feet tall in the garden.

: And of course, after everything is planted, the garden is given a good, thorough drink. I am looking forward to seeing these gorgeous blooms open later this summer. What dahlias are in your garden? Share them with me in the comments section below.