A report by Rob Lines on our meeting in October 2018 when Bob Brown spoke at our 30th Anniversary celebration.
To kick off, Bob recalled an order for 900 agapanthus plants that the client wanted to be planted out in the winter. Unfortunately, most of them did not survive – not due to the cold (they are very hardy) but because of the manure that had been added to the bottom of the trenches. Lack of aeration had caused the manure to rot anaerobically, adversely affecting the plant roots. The solution here is always to put organic matter on the surface, even on porous soils, and let nature (and the worms) work the material in. While on the subject of agapanthus, Bob said that one of the most popular queries on Gardeners’ Question Time is ‘Why has my agapanthus stopped flowering?’ Bob’s answer: don’t plant them in pots! Planting in the soil is preferable, in a site where the sun can access the neck of the plant. He also mentioned the considerable chore of dividing pot-bound plants.
Continuing on the theme of pots, Bob asked the purpose of crocks. Suggestions from the audience included saving on compost, improving pot stability by adding weight and, of course, drainage. To the latter Bob posited that drainage is impeded owing to the lack of capillary action between the pot and the ground. He also suggested that grit (but not sand!) is a better way to add weight while ensuring that the plant roots are properly aerated. The conversation then turned to pot feet – good or bad? Definitely bad, according to Bob, because it stops heat transfer to the pot from the ground. (Note to self – remove all feet from my pots!).
A popular service offered by the HPS is the Seed Distribution. Bob cautioned us that although annual seeds retain their viability well when stored, those of perennials really require to be planted straight away. So, don’t be surprised if the success rate for your sought-after perennial is low.
As a parting comment Bob said that he routinely uses unwashed plastic pots, as any plant worth its salt ought to thrive. After all, plants grow in dirt.