Last couple of years, due to global warming somehow bay area is cooler than normal. my 4 years seedling is same as yours. they start inflos then no flowers, branches out then growing last 2 years without inflos but this year, late inflos start around September but they are now in my green house for winter so I am not excepting for them to flowers.

I did experiment grafting and few has succeeded, but mother plant and scion are same diameter.

you can contact me so I can show you mine setup.

It typically does not work out well to graft to larger root stock. I'm not sure what is your intent. Graft a branch on the seedling to see if you can get blooms sooner?

IMO at this point in the seedling life cycle if it is about blooms it's best to concentrate on all the proven things to get blooms and not cut anything.

If they are too tall then consider down grafting (cutting out a middle lanky branch section and grafting back). That way you don't loose the potential for blooms. I guess another possibility is to throw in the towel on the seedlings and make them root stock. In that case I would look for a seller who will have a cutting with a comparable diameter.

Thanks for the replies. The grafting idea was to save time vs. rooting a cutting....plus seedlings are a crap shoot as far as color and flower form. I'm almost ready to give up getting the seedlings to bloom, and if they finally bloom at 6 feet, thats not going to make for a good tree under 8 feet, so down grafting sounds like a good solution.

I have a GHS about 7 ft tall, so I had to dig a hole in order to get my 8 ft tree in vertical.

I have only 1 plumeria which blooms each year, so its hard to say if some summers have been better that others. Last year bloom was sparse compared to 2 years ago, but this summer every tip had flowers. I think its the age/size of the tree in this case. When it was younger it would need to grow 8-12" or more before flowering, and now its maybe half that. My other rooted cuttings are showing similar growth habits w/o blooms.

You are right. Seedlings are a crap shoot. I will keep a seedling until I know what the bloom looks like and if I like it then I take cuttings from it all the way down to about 1-2 ft above the soil line and start it and the new cuttings from there as new plants. The root stock will typically grow back with some branching (hopefully) where it was cut and you end up with several good plants and a few middle sections. I may keep one and then gift or sell them.

It's kind of the same thing if the seedling isn't worth keeping (for various reasons like commonality with existing cultivars, etc.) I cut it up root the cuttings and gift them and the root stock too as a generic (pink, white, yellow, etc.) .