how much space you trying to cover?? .. wouldnt that be determinative???

ken

see link for potential ... also note latin name ...

i use google pix.. to try to see potential.. and then use such for planting guide ...

btw ... it can get rather large.. if not cut back every few years ...

ken

https://www.google.com/search?q=Cornus+alba+%27Sibirica%27&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiJqaW67NvRAhXl24MKHTeYDcUQ_AUICSgC

IME they grow fairly quickly and will sucker once established and so will grow together. I am assuming that you've chosen a full-sized one, not a smaller cultivar.

C. sericea tip roots quite aggressively, so can cover a lot of ground in a short space of time. It does need a groundcover. If the goal is the red twigs, then either a cultivar or C. alba is better than the species, but we are all just guessing until we know what plants we are all talking about.

NYS DEC is offering two: Red Stem (Cornus sericea, aka Red Osier Dogwood) and Red Osier Dogwood 'Ruby' (also sericea). They say "" 'Ruby; is a Natural Resources Conservation Service (NRCS) introduction propagated from a plant found growing in Painted Post NY. This is propagated by cuttings which essentially are clones of the original plant. They will be consistent in physical characteristics. This selection has exceptional stem-rooting (layering) ability for use in stream bank stabilization and soil bioengineering. Can be repeatedly coppiced, either for production of rooting whips or to maintain it as a dense hedge." The person I spoke to on the phone recommended the first as being the more vibrant red, but the descriptions sound like the second is the better choice. Mad gallica - would you recommend the Ruby in pachysandra? (I keep defaulting to pachysandra because of deer and it is just zero maintenance - no mowing, no raking, no weeding, and i find it attractive..)

I should have added, both are 6-9 feet, so gardengal's recommendation for planting about 4 ft on center should apply I assume...

Keep in mind that if it's red stems in winter you're after, cutting back a big planting will be a huge job. If it's just the full size plants, unless you need to stabilize a bank, you might find better shrubs.

I was wondering about that. Are they as tough to cut back as big grasses, eventually needing a chainsaw?

The seedlings you receive will be very small & you need to calculate a high rate of attrition. When I get little guys like that, I keep them potted up for a year or two before planting out. 25 is a large number to pot up so I understand why you're setting them out but don't expect them all to survive.

As I noted, the native plantings of redtwigs here never get cut back yet retain a lot of winter coloration so you don't need to cut back every year to still have winter attraction unless you want to. And they are not at all difficult to cut back or coppice, unless you ignore them for years - you just need sharp pruners!

btw, I think the pachysandra will make a very nice underplanting and suited for similar conditions. However, once the pachy takes hold you may not get as much tip rooting although the suckering will not be affected at all :-)