First let me say that I am not a gardener by any means and my knowledge of plants/flowers/gardening is limited. But I do have a question about cleome plants. My wife and I have been in our house for 7 years. Two years ago we noticed a small bunch of pink and purple plants that we never saw before. They were very pretty and the flowers lasted a long time, but they smelled like cigarette smoke. I found out after some research that they were (most likely) cleomes. Another thing I noticed is that they dropped a lot of seeds. So I thought the following summer we were going to be overwhelmed by cleome plants because of all the seeds that dropped. To our surprise there were NONE the following summer. And this summer there is only one solitary cleome plant about 10 feet away from where the group was 2 years ago. So my question is, why did these plants not exist for the first 4 years of us being in the house, then there was a small group one random year, then only 1 single plant since then even after dropping hundreds of seeds/seed pods? Are they like locusts where they only pop out once ever 17 years or something like that (im kidding)? Do they need really specific weather conditions and that one particular year was just perfect for the seeds to emerge? Please help solve this mystery. Thank you
My guess is that these seeds were originally deposited by birds or small animals in their droppings, having eaten them elsewhere, and the same circle of events has continued in your garden. Another, but less likely, explanation is that they could have been carried from a neighbour's garden by the wind. They are very easy to germinate from commercial seed, which is readily available.