Last week this Northwest region experienced what the media called ‘an atmospheric river’. Colloquially known as the Pineapple Express, this tropical phenomenon usually brings much warm rain and strong winds directly from Hawaii on occasion during winter. What was unusual was its timing – coming in June made us worry about trees and gardens now in full greenery. Fortunately for us dahlia growers, our plants were still short and largely unaffected. Once again, though, this brought up the need to support dahlias throughout their growth by staking or tethering those hollow stalks. Failure to do so may cause them to topple and break in inclement weather, ending their splendor for the season. 

Moreover, support also is needed for heavy bloom heads. Tying branches gives these better exposure to sun and makes maintenance easier. It also provides better air circulation - necessary to prevent disease in maturity. Certainly trussing a bush tightly must be avoided, because allowing some lateral movement strengthens both main stalk and its branches. An established method is to drive a stake next to the just-planted tuber, then tying the growth at one-foot height intervals. 

For home gardeners like me, stakes and ties are choices that are easily made. With a more limited planting area, I can’t be too generous with my space. Yet it allows me to plant 130 dahlias 18 inches apart. Cedar stakes (1x1 or 1x2 inches) are usually rip-sawed from 6-ft. cedar fence boards, because Western Red Cedar (Thuja plicata) is famous for its rot resistance, splits easily, is light-weight – unlike true cedars – and relatively inexpensive, when compared to commercial wood stakes. In time, though, even cedar stakes get shorter, so once they reach uselessness, they become kindling for the wood stove. All stakes get a coat of green paint, not for protection but to hide them better among the foliage. Likewise, green jute twine is chosen to be unobtrusive. Tied around each bush at one-foot levels, it stays strong until the fall dig. By August all but the tallest stakes are invisible, so that the dahlia garden can be enjoyed in its full aesthetic splendor. 

If the gardener has a smaller collection or wishes to place dahlias in different landscaped areas, then maybe one can consider these alternatives: tomato cages are suitable for dahlias, since such cages come in different heights and materials. If sturdiness is in doubt, a wooden or metal stake can be inserted to strengthen the cage some more. 

“What about bamboo canes?” you may ask. “They are as robust and inexpensive as wooden stakes, right?” Not so, according to Roger Walker. He had made the transition from one to the other some years ago. Roger reports that bamboo splits and shatters, forcing him to use gloves to handle them. Some also have sharp projections where leaf nodes once were. Their hollowness also invites pests that lodge in the pole, only to emerge for nighttime munches. To a gardener’s consternation comes one additional concern: Some dry bamboo stakes may root in the soil! 

After considering construction rebar - and dismissing this option as being too heavy and costly - the veteran grower settled on plastic-coated steel garden stakes. He purchased a large quantity in 4-ft and 6-ft length and recommends that buyers consider only half-inch diameter product. Sealed at both ends and featuring knobby protrusions throughout their length, the hollow stakes are rugged, yet light. Roger also learned that some brands are better than others. Admittedly, all these plastic-coated stakes will eventually weather, the coating will crack, and rust then settles in to separate coating from steel. 

So what can a dahlia grower with dedicated large beds do to ensure that even in inclement weather and heavy wind the dahlias remain protected? In the past even commercial nurseries relied on pairs of steel T-bar supports with strong poly twine strung all around these beds. Several versions of this simple support indeed have proven effective. It requires less attention to ensuring that all bushes remain upright - unless heavy rain and wind cause the collapse of a good number of the bushes. Kristine Albrecht offers a remedy in that she criss-crosses poly string in a pattern throughout the bed for additional support. (See Video)

The latest development in dahlia support systems was the adoption of plastic netting used for decades by growers of other flower products, such as carnations. Specifically, white or green polypro netting with 4-inch square openings have proven useful in supporting even tall dahlias. Solid posts or T-bars around each bed provide points of attachment. Some growers stretch only one netting layer at a foot height, but others add another or even a third layer higher up as the plants develop. While the netting is reusable, it must be removed with care before the fall tuber harvest can begin. This presents a challenge, as each layer first has to be cleared of foliage to permit rolling up the netting. After that is done, claim your stake as a net investor. 

How to Stake Dahlias Video

Martin Kral and Dianne Reitan, co-authors of the Dahlia Talk,

are shown here at the 2023 ADS National Show in Portland, Oregon.