You can root them all together, as long as they are not placed so close together that they rub off their leaves or buds and have a bit of air space between them. If you use a rooting hormone you should have a higher success rate, but forsythia is one of the easier plants to root.

I would tend to wait until after your forsythia shrub flowers, as the flowering process will probably use up the energy that would otherwise go into roof formation, but if you have enough sprouts to try it a couple of ways, you may wish to start some right away as well.. You can just prune off the shoots you need. Definitely try to start rooting them before the leaves emerge. Younger shoots will probably root more readily than really old, hard wood. Choose stems that are still flexible.

Include a few extra shoots for rooting, as not all will "take".
Watch the quality of the water, and replace with fresh water as needed so the new rootlets will not rot. They will need some light, but do not place in an area where they will overheat and dry out.

If the area you wish to plant is quite moist, you might try shoving shoots in approximately where you want new plants. If it stays moist enough, some of those may also root, saving you some time.

Forsythia will survive in part shade and eventually produce a fair sized bush, but it will grow much faster if it receives a good amount of sun. Probably in two or three years your border will begin to look more substantial, given the right conditions and the strain of forsythia you are working with.

Make certain to water your shoots well once they are in the ground, and continue to water as needed all the first summer, until the plants are established. One good watering a week is better than daily watering, as that would keep the roots too near the surface.

If you already have a row of soil prepared, I'm wondering why you would plant them all in pots? If you make your cuttings at least 18" tall and plant them so that 12" still shows, why couldn't you just plant them in the ground? Do you have a safer place to locate the pots? Admittedly, some rabbits may nibble on some of them....

If you mulch heavily after planting (leave space near the stems for watering) that should at least protect the roots over the winter, and next spring you may have more attractive shoots come up...if you have rabbits you might consider protecting your new plants with some fine wire mesh cages held in place by metal fence stakes, which if pushed down low enough will also help to deter mice.

Next year, watch your little shrubs' leaves; if they start to look as if they will shrivel or you have a dry spell, yes, I would continue with judicious watering.

Potting up a few extras to replace winter-killed plants would probably be a good precaution, too.

The regulars on this Forum may have some additional helpful pointers for you.

I prefer to use a somewhat longer cutting, as I feel this gives the plant more to work with in putting down new roots. Part of the stem will probably die and can be pruned off eventually.

Winter rooting can also be done with pencil-sized cuttings if you do not have a high enough success rate with rooting this spring and summer.

Good luck with this. I have started forsythia bushes in two different spots in my garden by simply pushing stems into the ground. When conditions are moist enough, they respond very well.

Eibren,

Thank you so very much for the taking the time to write such a detailed response- I really appreciate it!! I think I will try longer cuttings simply put in the ground. I'll have to order some rooting hormone- would you cover the entire 6" of the cutting that would be in the ground with it, or just the cut end?

I was originally thinking of doing them in pots on my deck so they were nearby, since I was thinking I'd have to be watering them every day.

You said to do one good watering a week- will that be enough for shoots with new roots? I kind of thought new plants needed more frequent watering since their roots were tiny and couldn't stretch down into the dirt to get more water (though watering once a week certainly would be better lol!).

I'm excited to try this! It's going to be blocking a view from my window where people are constantly walking by with their dogs at the edge of my backyard. As I type this some annoying person just strolled by!

I'll do it right after the forsythia blooms. That's probably going to be before the last frost date- will the new cuttings be ok in the ground if it freezes or if there's frost?

Thanks again!! :)

Forsythia really is very easy. If you have plenty of material you can make a hedge just by pushing cuttings into the ground in a line. It certainly works in my climate - I don't know what yours is like.