I thought this week was timely to talk about dahlia tubers that send out multiple shoots. At this time of year many new growers ask whether multiple shoots are OK to keep or whether they additional shoots should be removed.
The answer to this depends on the reason you are growing and a few different growing conditions. Those that are growing specifically to show/exhibit their blooms will tend to have only one main shoot, which they don’t pinch. They will also disbud the small side buds. These steps encourage the plant to put all of its energy onto the single bloom being produced, with an aim of producing the largest and best quality bloom possible. This comes at the expense of quantity of blooms, which of what most of us as home growers and cut flower growers are seeking.
I am not growing for the purpose of exhibiting, so I am trying to maximise the quantity of the blooms my plants are producing which I can stuff into cases and fill the house. In this case, multiple shoots, each of which I pinch out, are a way of producing more blooms from each plant. Some tubers will only produce a single stem, other will produce multiple. Clumps of tubers and pot tubers (small, condensed clumps of tubers grown in a pot) will produce multiple shoots, which is perfectly healthy (vs leafy gall which is not). If you accidentally snap off a newly growing shoot from the tuber, the tuber will generally send out multiple new shoots from that same growing point. The attached photos are both single tubers of the same variety, one sent out a single shoot, the other sent out 3.
There are a few things to be mindful of when having multiple shoots;
Ensure your plants are spaced far enough apart to allow for the extra space multiple shoots will need. Adequate airflow it critical for happy, healthy plant and also makes pest control more manageable. For this reason, if I have multiple shoots growing I will usually limit each plant to 3 x shoots. I plant 40-50cm spacing, and with multiple shoots they often still require some thinning out as they are reaching maturity. Some varieties will be naturally fuller/larger plants than other varieties, so from season to season it helps to record growth habits such as height and form of the plant to help better inform your planting plans for next season. Narrower plants can be spaced closer together, and fuller plants can be given the extra space they need. Height of the plant is also important to ensure shorter plants are positioned to maximise sunlight without being overshadowed by the fuller and taller plants which can inhibit the growth of the shorter, smaller plant.
Whether you grow each plant with a single, or multiple stem…..remember that a well spaced, adequately watered & fertilised plant with a good pest control routine will provide the best chance of maximising blooms. Frequently cutting blooms, and dead-heading regularly if you are leaving blooms on the plant will promote new growth and new blooms throughout the season.
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Happy growing everyone!
