It doesn’t feel like long ago that I was walking into the Gardens for the first time to start my project back in 2018! Now, in the final year of my PhD, I find myself reflecting on what’s been achieved so far. None of the work would have been possible without the support and dedication from both the Horticulture and Science departments at the Botanic Gardens. From helping me build the trial plots in the gardens, to training me up on DNA metabarcoding in the laboratory! Everyone is more than happy to help, and I feel very lucky to have had the opportunity to be based here for my PhD.
Over the last two years, I have used both observational and molecular techniques to investigate which plants that wild pollinators are visiting in trials of annual flowering seed mixes, sown in 40 trial plots at the Gardens. The results of this work consist of almost 5,000 plant-pollinator interactions, from June to November, which are now being analysed. By using a combination of both observational and molecular techniques, I can build up a detailed picture of how wild pollinators, (including hoverflies, bumblebees and solitary bees) are using the seed mixes over a longer period of time. I hope to get a better understanding of what additional resources that the pollinators are using in the surrounding area. Early results highlight the need to include a range of different shaped flowers within a seed mix to attract a diversity of wild pollinator species. Keep an eye on our science blog for more updates!
Sowing your own annual flowering seed mix
Here are a few hints on sowing an annual flowering seed mix in your own garden. This advice is based on the hints and tips I received from our helpful horticulturalists during the beginning of my research.
Firstly, what is an annual flowering seed mix? This is a combination of flowering plant species that will live for one year after sowing before producing seeds, which will become the next generation of plants the following year. Annual plants are quick to establish, meaning they provide instant colour after approximately six weeks from sowing, benefiting both us and the insects that feed on them.
Prior to sowing, soil preparation is vital. Clear the area of weeds, so that you are left with bare soil. This creates enough space for the seedlings to establish without being outcompeted by other plants. Once the area is clear, rotavate if necessary and rake over the soil to create a fine tilth. This makes it easier for the seedlings to establish and begin to germinate.
Sow the annual seed mix between April and May. To allow the seeds to disperse evenly across your plot, mix with approximately with two thirds of sharp sand before scattering the seeds onto your plot and tread in to create contact between the seedlings and the soil. This prevents the seeds being blown away in the wind. There is no need to cover the seeds with soil but they will need watering unless, like us, where you live gets plenty of rain. I would also suggest using a light netting over the patch or a scarecrow, to stop the birds from eating your seeds before they have chance to germinate. After a couple of weeks, the seedlings will begin to emerge and hopefully after around six weeks they will begin to flower, inviting pollinators to your garden.
Once the species have stopped flowering and have set seed, mow off all the vegetation and remove the cuttings. Rotavate the soil again, creating a fine tilth to allow the seeds to emerge next year. Alternatively, to create an area for small mammals over winter, you can leave the vegetation and cut back and rotavate in the spring. You can collect the seeds and try them on a new patch, though I think it’s nice to leave a few for the birds to enjoy. The success of your seed mix will also depend on the weather conditions and your soil type.