I have been gardening for over 40 years and only learned about the salvia and mirabilis tubers a few years ago on this forum. My Mom grew long rows of 4 o'clocks (mirabilis) every year in our big farm garden. She always started them from seed. I asked her if she knew that they formed tubers but I asked too late as her memory is going and all she said was "I don't remember."

I would think in Z:9 you would not have to dig up the tubers for winter storage so might think they grow like most other perennials. Chocolate cosmos, sweet potato vines, canna and calla lilies also form tubers. When I lived in St. Louis, MO I did not dig up the calla lilies as they survived in the ground and grew as perennials.

I know that some over winter geraniums with bare roots but that did not work for me. Mine go dormant in a pot in a dark cold basement room with a little water once a month until spring when they start growing again. I have also kept them growing and blooming throughout the winter by an east window or under lights.

I thought I knew a lot about flowers too until I decided to try WS..I always bought the starter plants from nurseries and garden centers..I now appreciate what all is involved. I myself didn't know about Four o'Clocks having tubers either, so you're not alone. This website has a lot of knowledgable and creative people and they are willing to answer your questions and show you their gardens through photos if they can. People on this forum bend over backwards to help you; they have become my WS family. We all learn from each other and I'm sure you'll be able to contribute something maybe somebody who post here may not know. We were all Newbies at once, keep that in mind.

I pull up my geraniums every year. I've not had to buy any for nearly 5 years. In late fall I clip them down to about 10", pull them up, keep whatever soil clings to the root ball, and stand them up in a plastic tub (like an underbed storage unit). Then I put them in the crawlspace (note: my crawlspace never freezes and has windows so gets some light). Then, every 5-6 weeks, I'll pour a little water into the tub so lightly hydrate the roots.

I lose maybe 20% every year, but no matter. When it's time (like late March) I pot each one up with new MG, bring them into the warmer basement and new shoots come out of the old stems. Those with nice sturdy long (old) stems, I cut them back to a juncture, dust them with rooting hormone, and stick them into a little pot of MG. These root and voila! I have all new plants to replace those that didn't make it in the crawl space.

Here's a link to my last year's blog post about it.
Melissa Majora - roots and tubers

Last year I even found a packet of geranium seeds. So I started those too. The one's I WS'd did not fare well, however. Only those I sowed in the basement germinator came up. If I find more seeds, I'll try WS'ing them again this year, just maybe later in Spring (like annuals).

Hope this helps. Good luck!
Kris

Four oclocks grow hudge potatoes.Here in zone 7 they are perennials and take over everything in my beds. Ihave to put them in a place all to themselves they are not allowed to socialize with the others flowers.

I didn't know I would find tubers when I decided to dig up the Four o'clock in my tubs. I stuck my hand down into the soil to pull the roots, and much to my surprise I found tubers too. I over-wintered them in the house in a brown paper bag, not knowing what to expect. Last week I took them out and noticed they were starting to sprout! It was a very nice surprise, and now I won't have to start them from seeds this year. Who knew??

Mary