Q: A friend of mine recently gave me some cleome seeds from her garden. She said her plant was self-seeding. What do I need to do with these seeds…and when?
A: Cleome self-seeds to a fault but the flowers are beautiful. My friend Patrick Bartkus showed me a photo of his wife’s garden and challenged me to detect what was wrong with the picture. When I admitted defeat, he pointed out that there was only a single cleome in the picture. “When do you ever see that?” he demanded. “If you have one cleome, there are usually hundreds beneath it! I pulled them when she wasn’t looking.”
Cleome is a tall plant so choose a planting spot in the back of your flower bed. Scratch the ground there next April and scatter your seed. Cover with a bit of dirt and they will sprout in three weeks. The pink-lavender flowers are very attractive in mid-summer but most gardeners find the plants leggy and unattractive by August. You can prevent this by removing each flower stem, even if it has a flower on it, when it is twelve inches long on the end of a larger branch.
Remove the faded plants next fall but note that the trunk is lined with slender seed pods, many of which will have opened and scattered seed by that time. This is what your friend meant by “self-seeding”. Regular cleome grows 3 – 4 feet tall; the variety ‘Linde Armstrong’ grows only 12 – 16 inches tall but doesn’t self-seed so vigorously.