Beautiful plant, but be very careful. It can be extremely difficult to remove from unwanted areas. A raised border planter won't necessarily be sufficient to contain spread--it can send rhizomes down and then laterally. (Picture down a raised planter and under a 3-4' concrete walkway.) If brave enough, I would put it in a solid bottomed planter with just drainage holes below, on top of solid concrete. And then be very careful with the pruning pieces. Definitely do not reuse the soil. I love the look of the plant, but don't dare introduce it into my CA garden.

Yup, agreed on the ID. You could probably take cuttings a few nodes long & pot them back into mother plant's pot, to make it look even more full & lush.

Thanks for the kind words Dee! The keys for identifying the 4 different varieties are basically measurements that must be done with the plants in hand. Usually when a variety is given species rank, it is a variety that looks distinctly different, and that's probably the case with the 4 triloba varieties. It may be possible for 2 species to resemble each other, but have quite different DNA, which would warrant being lifted to species. I've already pulled out a few R. triloba this spring. I'm sure that I deadheaded them last fall. I had a big R. hirta that flowered it's head off and I let it go to seed, but I haven't spotted any vollunteers. I grew a double flowered Rudbeckia laciniata called something like Flora Plenna several years ago. I didn't have it for very long, because I could tell it was going to be a major thug. I tried planting a few wild laciniata a few years ago, but the deer ate them entirely to the ground. Now I have Helianthus divaricata and Helianthus groserratus taking over thug duty in that area. The deer like the taste of them too. I bought my first submentosa at a native plant sale on Saturday. I want to get Henry Eilers because me and Henry are friends. Henry is a botanist with a vast amount of knowledge about native plants, prairies, restoration and degradation. He's 88, but gets around better than some 60 year olds. Your 3rd photo of triloba has more sharply pointed leaves. It could just be a phenotype with slightly different genetics. There are a few different Cornus/Swida species that occur in Conneticutt. Can't say for sure which one your's is. It's definately not C. alternifolia, because your vollunteer has an opposite leaf arrangement. C. floridus and C. amomum are possible. A few others are possible too. I do see a benefit to calling the tree forms Swida, because it seperates them from C. floridus and the very different C. canadensis.

You could put it out in summer and bring it back in over winter. But these are usually treated as short lived indoor decoration since they're tricky to keep happy long term. They rot off easily if not carefully watered and they don't like heat or dry air. If you plant it outside it will be killed by the first frost.