GARDENPlants and seeds

Can I grow these flowers in jars until they’re seedlings?

Hollyhock, Zebra Mallow, Blue Passion Flower, Giant Milkweed tree, and Swamp Milkweed.

As long as you don’t over-water them, the only problem will be getting them out of the jars (if you mean glass jars) when it’s time to transplant them.
Vines usually grow better without transplanting, though, so you might wait till you can plant the passion flower directly into where it will grow.
With the others, you’ll just have to be careful not to disturb the roots unduly when it’s time to transplant them. If you can get the whole ball of dirt out in one go, then you should be okay.
Personally, I’d stay away from glass. Just too easy to have an accident. You can just as easily use things that don’t shatter, like metal cans or plastic jars, if you can’t get proper starting containers to use.

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