Q: How do I eradicate four o’clock plants? The previous owner of my house planted them everywhere.
A: This is another plant, like clerodendrum and sweet autumn clematis, that has attractive flowers but can be a garden thug. Mature four o’clock plants have a fleshy potato-like root that helps them to recover from herbicides. Digging them up is a good technique if you have a small area. If you decide to go the chemical route, a product that contains glyphosate plus triclopyr will work pretty fast but likely won’t give complete control. Keep an eye out for small sprouts next spring and dig them up.