The recommendation is to avoid fertilizing new plants added to the garden - they generally do not need any supplementation in the first place and transplanting/planting often creates a stressful situation and you definitely do not want to fertilize under those conditions. Just plant and water. I like to use compost for mulch and this will provide any nutrient needs that might be present. Otherwise you can apply compost in spring or other commercial fertilizer if conditions warrant.

Any recommendation for fall fertilization is usually restricted to woody plants and to be done after the first hard frost with a low nitrogen formula

in my z5.. ground freeze MI. i will yell.. NEVER FERTILIZE AFTER 8/1 ... EVER!!!!

made too many mistakes and killed things over the years ...

they are plants.. they are not children.. and i swear i have told you this before .. lol ... they do not need to eat.. nor be fed.. presuming you have a decent soil ...

and trust me on that.. because i do not fertilize on mineral sand.. which is basically beach sand [no salt issues, its a glacial thing] .. and nothing fails to prosper.. for such .. [of course water management is the BIG!!! problem] ..

all that said.. a little of this or that.. shouldnt hurt..

the issue is that your plants be slowing down as the first frosts come.. and definitely by first freeze ... which for you warm zone folks.. i am talking 10/1 ... in MI ... and lets just pretend.. thats like 30 days ... ya know.. with thirty days.. can it even get into the soil.. and processed into the plant.. to do much of any good???.. i wonder ... anyway ...

anyway.. doubt you could do much harm with something light and fruity.. like a fine 1976 rose' called.. 12-12-12 ... broadcast VERY sparingly ...

and i said broadcast.. i would NOT be putting it in the planting hole.. down 6 inches.. because of the activation time.. and the cold issue ...

very frankly.. i would water them in well.. mulch them for winter..

and in early may.. then give them the fert ... safer all around in my world

ken

ps: one year.. i killed about 50 of my 100 hybrid t roses.. thru fertilization.. never again ... the roses.. nor the fertilizing .. lesson learned ... feed them when they are starting to.. or actually growing.. not when they are supposed to be going to sleep for the year .... and again.. if you are z7 and up .. and winter is 45 minutes in mid january.. we z5'ers.. dont live in your world ..

What about compost or garden soil in the planting hole. The planting holes will be in uncharted lands and I doubt the soil has many nutrients

If you need to amend, do so over the widest area possible, not individual planting holes. It has been documented that plants in unamended planting holes establish faster and thrive better than do those in amended holes. What comes out goes back in. Use your compost or amendment of choice as a mulch or topdressing instead.

Naked or indigenous soils have a lot more nutrients than you would imagine unless they are highly sand based :-) The need for routine amending and fertilizing is highly overstated, typically promoted by those with interests in the fertilizer/soil amendments industries.

Ken, fall fertilizing for hardy woody plants is highly recommended. As long as the soils stay warm - and they cool far slower than do ambient air temps - roots remain very active and in a period of high elongation, more so than at any other time of year. Supplementation with a low nitrogen fert (if any fert deemed necessary) or any organic formulation is metabolized best at this time of year and helps to prepare the plant both for winter and new spring growth. The same theory applies to perennials.

Gaillardia (Blanket Flower) does not demand many nutrients and in fact thrives in sandy, poor soils. I wouldn't use anything except some compost mixed with native soil in the planting hole. It must have well-drained soil as winter wetness will kill it. It really needs to be shutting down flower production well before frost or you risk it not surviving winter, so many recommended cutting Gaillardia down to 4 inches in early to mid-September (depending on your expected date of first frost) to encourage development of strong basal foliage before frost.

Rudbeckia (Black-Eyed Susans) are also wildflowers that do not require a great deal of nutrients to flourish. Therefore, I would recommend compost for them as well.

so let me get this straight and a little off topic.

When planting or a new plant (anytime), you should not put compost or fertilizer into the hole??

I always have

I have gotten away with a lot of mistakes also, but when I know better, I stop pushing my luck. Al

dcrosby, my recommendation was that you should add compost to the planting hole for aeration and soil conditioning, but for the particular plants you mention, there really isn't a pressing need for fertilizer. Gaillardia really needs drainage more than anything. Rudbeckia is pretty much bulletproof in my experience.

That said, for plants that could benefit from it, I mix some slow-release granular fertilizer (Osmocote) mixed with the soil at planting time. This won't hurt anything, but some plants actually resent rich soil so you have to amend the soil based on what particular plant you are planting.

I would do this whether planting in Fall (so the plant can get established before frost) or Spring.