Boosting the population of natural helpers
Early flowering is vital to support a good predator population in June and July. Alyssum was the first to flower (average 10th June) but buckwheat started flowering only 5 days later, and continued to flower for a longer period of 88 days, the longest duration of all the species tested. It was also the most reliable at flowering, and the most vigorous with 90% of participants stating it produced many flowers covering the plant.
Different plants attracted different numbers of hoverflies in different months through the growing season. Alyssum attracting the most hoverflies in June, whilst coriander, phacelia and buckwheat attracted far more in July. Buckwheat and phacelia attracted most in August.
Overall we think buckwheat was the most solid performer. It may be the least familiar of the plants but it deserves to be grown more widely. It was reliable, vigorous, rapid to flower, and attracted predators over the longest period. As it is so rapid to flower, we would recommend throwing a few seeds down whenever you have a bit of spare growing space to bring in a few more predators.