Mirabilis multiflora aka Colorado Four o’Clock is a beautiful native plant that blooms from April to the first freeze. This plant survives on the water and food that is available to it and produces thick stemmed stands of plants 36 to 40 inches tall. It is drought tolerant which makes it ideal for the hot summers in my part of Texas.
This species can become a problem in the home garden because it spreads by underground rhizomes. The rhizomes of this species are found between 2 and 6 inches deep in the soil. Periodic rhizome trimming with a shovel can train these guys to where you want them. Some folks put them inside pots buried in the ground to keep them contained. We have a flowerbed where the roses are surrounded by these and they can grow tall enough to dominate them. We just prune the rascals and they grow back.
In the winter we cut them to the ground and watch them pop back in the spring. I recently dug up the rhizomes near the roses; unfortunately, I missed some and we had another crop of Four o’Clocks. I was satisfied with the reduction in numbers, and I plan to keep them in check this way. If you like pink tubular flowers throughout the spring, summer, and fall, these guys will make you happy. They thrive on irregular watering and feeding and they don’t seem to need as much as other landscape plants except where their vigorous growth requires trimming.