Musk mallow madness

These are incredibly hardy perenials that seem to grow, if not thrive, under any and all conditions. The first year that I planted it, I overfertilized and they grew to be over four feet tall. In an area with no fertilizer they gew only one foot tall. Apparently under the correct conditions they will grow from two to three feet tall. Whatever the conditions, they bloom profusely from the end of June right up to the hardest frost. I really like their fern like leaves, and the flowers look like very tiny hollyhocks to me (not surprising since they belong to the same family which includes the hollyhocks, the malvas (of which the musk mallow is one), the mallows and the hibiscus, and most surprisinly the vegetable okra).