For years I have grown Cleome hassleriana in my main garden border and considered it one of the mainstays of my summer display. In recent times, however, I have grown tired of it. Perhaps this is because of the hotter summers we have had lately - the hot sun makes the petals wilt so the flowers don't look attractive during the day. They also become very lanky as they age; they are sticky and have thorns on their stems; and they self-seed quite aggressively. I grew seedlings that came up each year so quite a bit of space in my border had to be kept free for the seedlings to emerge each spring, so it looked rather bare for a long time. I have now developed a fondness for a Cleome hydrid called 'Senorita Rosalita', which is a more bushy version, and is perennial in our Sydney climate. It grows to around 1 m tall and has pretty purplish-pink flowers over a very lengthy period: in fact, almost all year round!
It likes a sunny, dryish position, and copes well with our increasingly hot summers. It is not sticky, has no thorns, and does not self-seed. What's not to like? There is also a white form with a pink tinge to the buds and dark stamens called 'Senorita Blanca', pure white 'Senorita Luna', and a pastel pink cultivar known as 'Senorita Carolina'. The plants can be trimmed back when they become leggy and they will reshoot; however, I have found that after about two years, the plants seem to exhaust themselves with all that flowering, and need to be replaced by a cutting - which fortunately strike quite easily!
I am not sure of the correct species name for this plant but I have seen Cleome spinosa on plant labels for these cultivars.