I may be wrong here, but I don't think you need any fertilizer at all. For now, your new shrubs will be busy re-establishing their root system, rather than trying to put out a lot of new top growth. They may not look like prize specimen this year, but will be much healthier in the years to come if they start out with a good root system. Fertilizer might just add stress at this point.

When I plant shrubs and trees, I amend the soil with compost and some good loam if necessary. And I always, always, no matter what I plant, add a good measure of bonemeal into the hole. The bonemeal will encourage root development. I swear by the stuff.

After planting, you could mulch with compost and then wait until next spring to apply some shub fertilizers if you feel that is necessary. If your soil is good with enough organic material, I don't know if you'd even need much of it for the species you are planting.

Just to clarify, it isn't recommended that you amend the back fill of your holes with compost or anything if planting hole-by-hole. Plants actually do much better, in the long AND short run if planted right into the native stuff (whatever it is) and using that same soil as backfill. If you are preparing an entire planting bed with a rototiller, that's a different story.

Woody plants really don't need to be fertilized for the first year after planting. Chris is right on about that.

So....simpler is better, after all!

Rhizo, this is the second time that someone mentioned that it's not a good idea to amend hole-by-hole, but I've not found a good reason for it. Can you point me at some articles that explain this theory?
It would be a hard habit for me to break, given the excellent health of my gardens. So, the more info on this, the better!

C.

Rhizo might have a different response, but do you mind if I take a stab at it? I think the theory is that the roots will be happy in all that great ammended material in the hole & may not feel like reaching out into the unammended stuff because it's not as rich. Of course we want our plants' roots to reach out, and we don't want them to remain only in the area of the planting hole. IIRC this is a relatively new theory in the gardening world and all may not agree w/it. It certainly makes sense to me but not enough to stop ammending my planting holes.

Phosphorus fertilizers tend to not move through the soil too well so you might want to put some high phosphorus fertilizer in the hole if your soil needs it.

Thanks, Mehearty
At the risk of hijacking this thread... I can see your point about the root thing, but many plants purchased in garden centers come in a bucket of very rich growing medium, depending on who produced them. So, these plants are already in rich soil and therefore reluctant to send roots into the surrounding area.

When planting, I generally dig a hole quite a bit wider than the plant's rootball - wider than the expected size of the root area of the mature plant; unless you're growing something insane like cannas or certain grasses, those rootballs tend to be of a reasonable size. So if I amend that hole those roots should be quite happy settling in.

Of course, planting shrubs might be an entirely different story, since they have larger root systems. So perhaps what works for my perennial is not as feasible for shrubs.

C.

More plants are stressed, killed, stunted, burned, by over fertilization than by under.
I break up the root ball of nursery grown shrubs, put it in the ground and back fill with what came out of the hole.
The professionals at the Arboretum, shake almost all of the soil off the roots of a tree before they put it into a hole and backfill with unamended soil.
That's the way the pros do it....and that's good enough for me. When you plant in a "pocket" of amended soil, you are essentially planting in a container in your garden, and the roots of that plant will stay in that pocket.
By the way, Rhizo is a horticulture professional. She earnes her living planting and maintaining plants, trees and shrubs.

Linda C