|Tying up Dahlias
Presentation for Portland Dahlia Society
by Ted J. Kennedy
I remember when I first was thinking about growing dahlias and being turned off by the fact that dahlias really need to
be tied up. Dahlias are generally tall growers reaching an average of 4 feet or so. Flowers do not look all that heavy but
when filled with dew or rain they are too heavy to hold themselves up. Branches fall over or lean over and flower stems
become crooked after that happens. Entire plants can fall over in a wind storm. So we need to tie up dahlias. I will
discuss the various methods.
(1) Hilling Dahlias: The first method is not tying them up but instead mounding soil around plants to hold them . This is
called hilling them up much as potatoes are grown. As most of you know, Swan Island Dahlias does not tie up their
dahlias. Instead, they use a small tractor with a device attached to move the soil onto the base of the dahlia plants. In
our trial garden, the flowers are also hilled up and the majority of them are not tied up but some are too tall and need to
be tied up. There are differences between your garden and the Swan Island gardens. Th biggest difference is that their
dahlias are grown in full sun with no shade at all. Just about all of us have our dahlia gardens in some sort of partial
shade and dahlias grow much taller in shade(as much as two feet taller or more!). Some growers use a combination of
hilling and tying up.
(2) One stake: The classic way of tying up dahlias is to pound in a wooden or steel stake(very few people use wooden
stakes any more). The dahlias are planted around the single stake. In full sun, four plants are planted about a foot from
the stake. If there is shade on one side or there is no access on one side, three plants are spaced around the stake.
Plants are tied to the stake as they grow. Phil Mingus used to use this method before he lost the lease to the acreage
next door. This method takes more space but is in my opinion the most esthetically beautiful way to display dahlias.
(3) Dahlias in rows: Many commercial operations switched to growing dahlias in rows because of the ease of
mechanical weeding by the use of small tractors and it is easier to tie up the dahlias. The first garden I saw using the
row method was Les Connell’s garden in Tacoma. This method is used by most commercial operations with a few
differences here and there. Most growers plant the dahlias in double staggered rows with about 6-10 inches between
the double row and spacing the dahlias at about 12 inches apart in the row. Usually a drip irrigation T-tape is placed in
the middle of the staggered row. Some growers do use overhead watering, however. T-Posts( usually six feet tall) are
used. The t posts are placed two on the ends of the rows and two every 10-12 feet along the row. They are about 24
inches apart. In my garden, I plant in 50 foot rows and use 10 t posts for each row. Baling twine(either 110 pound or 170
pound polypropylene) is run down the outside of the rows and tied to the stakes. I use two or sometimes three rows of
twine . Cross ties are placed every 6 feet or so to keep the plants from falling down in the rows.
(4) Criss-cross dahlias: Helen of Helen’s Dahlias uses a variation of the method above. She plants four rows of dahlia
about 16 inches apart and the rows are about 15 feet long. This creates a rectangle of dahlias. She places a t post at
the four corners and one halfway for total of 6 t posts. She then uses the baling twine to surround the patch and then
crisscrosses the twine between the six stakes. This pattern of twine holds up the dahlia plants from all directions. The
effect is both practical and quite pretty. You can easily reach all of the flowers even those in the middle.
(5) Plastic mesh: Some people are using plastic construction fence as a mesh to hold up the dahlias. You have
probably seen the bright orange fencing around construction sites. I believe that it has 4 x 6 inch mesh and is 3 feet
wide. It is tied to t- posts horizontally and I believe it is 18 inches off the ground. I do not know whether they use two
layers of mesh or just move to original one higher later in the year. The dahlias grow through the mesh without a problem
and they say that harvesting flowers and digging the tubers clumps is easy.