Show from Sep 2, 2007 Pyrethrum daisies

Good morning gardeners. It’s another beautiful day in Manitoba. Who would believe it would be plus 33 on September 1, but that’s what my thermometer read yesterday afternoon. The annuals are just loving it.

I was busy watering the potted annuals and thinking about how well they are doing. I even gave them a little shot of fertilizer to keep them happy a couple of weeks longer until the first frost, which in Winnipeg is usually September 22. Not that the petunias will probably succumb to the first frost unless it’s a very heavy one, but there is little growth after that.

But even with the lovely weather, certain potted plants look the worse for wear, while others are absolutely stunning right now. Those containers filled with foliage plants are really lovely att this time of year and impatiens are at their peak. But I wanted some big pots of chrysanthemums, so I headed off to Shelmerdine because Jan told me that he potted up a whole big mess of them. Sure enough, the greenhouse is filled with these beauties, just starting to come into bloom.

Chrysanthemums are photoperiodic as you know and many of them need shorter days to bloom.

One of these chrysanthemums is particularly interesting as it is the source for pyrethrum, a powerful insecticide that is coming back into favour. Its common name is pyrethrum daisy and it s botanical name is Tanacetum cinerariaefolium. It originated in China and has been used since the first century A.D. against insects with very little toxicity to mammals.

The dried petals were used in the 1800s as a lice and flea repellent. As late as 1946 in Amsterdam, pyrethrum was added to the municipal water supply as an insecticide with no effect on the population. It was also used to delouse troops in Napolean’s time and again in World War Two. Today, 70% of the world’s pyrethrum crop comes from Kenya, but the daisies are also grown in Rwanda and more recently in Tanzania, Australia.

It’s a pretty flower, typically daisy-like in appearance with white petals around a yellow centre. It blooms well for up to five years in fertile soil with lots of sun.

Well, Jan Pedersen is with me today to tell us all about the fabulous Chrysanthemums he is growing over at Shelmerdine and to let us know just what’s going on at the greenhouse. Good morning, Jan. Go to Top