Rose Mallow Hibiscus

[Ralph D.]

Rose Mallow Hibiscus moscheutos 'Lord Baltimore'.

Picked up one of these yesterday in our new quest for late to very late blooming perennials for our large rural SW PA zone 5/6ish perennial garden. Years of work are paying off now, but it goes away too soon.

Anyhowz... what we're considering is plopping this thing (and maybe more in the future) in the middle (and later, ends) of our 3' X 12' iris bed. This bed really is the focal point of the garden in the spring (being nearly centered) as it should be, but by this point all that irisy looking scrub detracts from all the other great stuff going on in there. I thought that somehting like these, with their 10" blooms might dress it up.

How well do these hardy hibiscus play with others? Is there anything about the iris rhizomes that will compete with it for nutrients or whatever? This bed is slated for digging up and dividing this fall or next, and I was wondering how the mature root system might affect them in future years? This garden is being done with the very long-term in mind and I want things that I can do there that simplify, not complicate things.

I see many links for this variety, but they all seem to focus on the monster blooms and never show the whole plant. I need to confirm whether this grows in one 'trunk-like' shoot or many shoots that might put a whole in the middle of the iris bed, and so-forth. Sparse folliage is a real good thing for this spot which adds to it's appropriateness, so long as I do not do anything to disrupt or diminish what is a spectacular iris show of colors that carefully fade to the next.

Any thoughts on this or anything related?

[Tyra Trevellyn]

My first thought is really a question: What Iris species do you grow? If you're growing German bearded or other Iris that likes dry soil, you might want to consider that Hibiscus moscheutos likes moisture.....it's basically a wetland plant. Rose mallow and the German Iris hybrids would be a difficult partnership.

Best, Tyra nNJ usa z7a

[Alan Sung]

I have several rose mallows. They like full sun. They are multi-trunked with each trunk about 1 to 2 inches in diameter. The root system can be fairly wide and extensive. Max height is around 4 to 5 feet. Lots of big foliage so things underneath don't grow so well. As the season progresses, the leaves towards the bottom and inside tend to die off. Max girth is about 6 feet in diameter. The giant flower lasts about a day and the plant needs tidying frequently. The old big flowers tend to "melt" onto the foliage or fall to the ground and get moldy. This perennial goes dormant after the first frost and you need to trim the trunks back down to the ground. The flowers are definitely impressive but I'm not sure it would look right in a bed of irises. It's more like a standalone shrub.

-al sung Rapid Realm Technology, Inc. Hopkinton, MA (Zone 6a)

[Ralph D.]

Thanks for the replies Alan & Tyra.

These are, in fact, bearded iris... but they seem to be happy in what is, really, a fairly wet and poorly draining bed. The soil is *very* heavy there to the point of amending doing little to help. I am surprised that the iris are so happy there and attribute it to them apparently liking the nutrient make-up. That's why I do not want to disturb that aspect of it. I think the hibiscus would get the moisture it wants there, and the bed is so large and ratty looking that something tall and striking might take away from that ugliness, especially if it does not start growing until the iris bloom cycle is about over. So... I guess my only concern is that you are noting this particular hibiscus to have a large root system, which would not agree with the occasional dividing and replanting of the rhizomes. Hmmmmmmmm... that's what I need to get more information on, specifically, I guess.

I must find some sort of flowers that can share that bed happily, considering the poor soil and drainage and all. I tried setting pots of Lantana through it this year, and while it was an idea that seemed good, they are just too dainty to make up for 36 square feet of brown, gray and green iris scrub.

Thanks again for the thoughts.