In general, spring and fall, when the weather is cooler are the typical time. That being side, you can do this work anytime, but you will have to water, sometimes daily, in the heat of summer. Your choice.

the key for me.. is night temps ... when it gets lets say cold.. at night ... say.. under 60 ...

then the plants have a long recovery period from whatever the day sends at them ... so even if it hits 80 for a few hours during the day.. it would cool rather quickly in the evening ... and even if it gets hot.. the soil... under mulch... stays cool ...

it also means.. not as much water is pulled from the ground during long hot spells ...

so if you move things.. water them in real good.. and mulch proper.. and then wet the mulch ... it might be weeks.. before you lose moisture at depth.. where the roots are recovering ...

thats how in works in my MI ... which has to be very equivalent to you ... how different can it be.. the further south you go ... other than what month it happens ...

very infrequently.. there is drought in november.. and a good drink might help .. which means you cant put your hoses away 10/1 .. like so many peeps ... but this is rare ...

one caveat ... in the north.. its hard to buy mulch in fall ... either bagged or bulk ... so if you think you will be using a lot.. secure it now ... dont wait until you cant get it ....

ken

btw: does your ground freeze?

When we plant - spring or summer - we dig a fairly large hole and fill it with water, and let it drain out before planting. After it drains out, if the soil still looks dry - as it might with summer planting - we refill the hole with water and let it drain again before planting anything in the hole. We don’t mulch in the beds, only on paths, relying on dense planting to function as much so it is important to us to ensure the soil is moist before planting, especially in summer. While fall is considered a good time for planting, I have lost more things planted in the fall than things planted in spring or summer! Cool nighttime temperatures that start happening around now are useful though.

I just bought four Winterberry shrubs the first of this week. l'm going to wait until a couple weeks or first part of Sept. to plant when hopefully it will be cooler. Right now the ground is so darned dry anyhow, digging a hole will be a chore.

Usually I don't have a problem planting in the Fall, shrubs or perennials.

If you're in 6bNY, you are probably not far from me, and I won't be moving or planting until mid-September, as much as I want to rush out and move them NOW. Our ground won't freeze until December or so, so the roots will have a long time to get settled, even if it's October. Hide your shovel so you won't be tempted.

this is when you do all your prep work ... so its easy in fall ...

in fall.. the usual rule is 6 to 8 weeks before ground freeze ... which is be done mid october ...

and in spring.. 6 to 8 weeks before the heat of summer hits... which for me.. is late may.. which coincidentally is last frost/freeze time ...

this crossed my mind earlier ... do it when its sweatshirt season ... you may need to take it off as the day warms.. but you better have it on in the morning.. and in the evening ... wonder if i will remember that new rule... lol ...

ken