I don’t know if the species of lilacs that includes Miss Kim, Syringa pubescens subsp. patula, suckers like common lilac, so I am not sure if this is a shrub that can be whacked in two and survive.

i would likely wait until the end of September in your zone, not long before the leaves are likely to drop, though you could move it sooner if you want to do a bit more care. After moving, mulch well and keep an eye on soil moisture, not soggy, but not dry. If you move it earlier, you may want to rig a temporary shade during the hottest part of the day. Be aware that it is tough to maintain a smaller size by pruning a large sized panicled hydrangea since they regrow quickly, within a season. If you prune after the buds start swelling in spring, you may lose flowers, so you want it where it can grow to near its full size.

i would do it when its dormant ... even better after the leaves fall off ... avoid all the stress of trying to maintain them ... when the plant should be shutting down ..

see this link.. section one on timing ...

https://sites.google.com/site/tnarboretum/Home/planting-a-tree-or-shrub

leaves are food making machines.. you are in a catch 22 wanting to severely cut back a large plant ... removing all of next years leaf potential ... but on the other hand.. how much easier the job will be ...in other words.. it might not be best to transplant.. and cut back ... two different projects ...

without a pic.. its hard to opine.. but i might reduce it by half... and give it another year or two.. after the move ... before i begin hardcore rejuvenation pruning ....

btw.. plz clarify ... its too big where it is.. so you want to move it.. but then.. it sounds like it will be too big in the new spot hence the idea to whack at it .. perhaps its time to just get rid of it ... and plant something better sized to your wishes ...

lilac is not a perennial.. in the sense that you can divide it ... propagating lilac is usually along the lines of harvesting suckers off the sides ... if kim is that type ... what babs said ... the key with suckers.. is that they usually have some root on them.. and that little root is enough for the little plant ....

i would be concerned cutting off half a large plant.. and hoping there would be enough root mass to support it ...

in my MI .. i would do it in late September .. basically when the trees are starting to color or drop leaves ... thats a very good indication that everything is going into dormancy .... for your RI .... that should be about the same ...

ken

https://duckduckgo.com/?q=Lilac+miss+kim+propagation&t=ffcm&ia=web

Here are the photos of the two shrubs.

Thanks ken and bab so the consensus is to do it this fall? My thought was do it just before it starts waking up (next spring like march?) - the time period between moving and they wake up is shorter the less chance it will go wrong?

Yes, The hydrangea will outgrow the location it moved to. I wanted to try to see if I can dig it out at all. If it is too hard. I probably just give up and prune it instead. :)

we've moved 3 lime lights..they weren't full but were 6 ft tall..we don't have enough sun to grow beautiful specimens but they give us some screening below our towering trees..decided not to keep them in front and I thought rather than "shovel pruning" why not move them and fill gaps..they were tall and free!..all were moved in the summer..I remember one was moved on the 4th of July..that was before we retired and we had the day off..so far all are alive and well..I was faithful about watering after the move..

I have divided a few shrubs successfully. They include bombshell hydrangea, two itea little Henry’s, and sunjoy pillar barberry. I used a saw, and paid special attention to watering...

I never move or plant anything in the fall. I like spring planting because then the plant has the whole spring and summer to grow roots and settle in. Planting in fall, I lose plants from the freeze/thaw/heave/freeze cycles. You'd have to do a lot of winter protection to keep that from happening.

I think when is best for transplanting may depend some on your soil. I have sandy loam soil and have never had a shrub have issues with not surviving a fall planting if it was fully hardy for me. Even perennials almost never heave. The sum total of my winter protection is mulch over the roots and keeping an eye on water until freeze or snow. In autumn, the soil is warm but the air is cool and days short so there is little stress on the plants. Even perennials rarely heave or have any problems with fall planting. I have lost about 1/4 of my spring-planted plants because the days are long and often hot while the soil is still cold, so the plant has leaves being pushed out, but not much if any root growth until the soil starts warming, so the plant comes under a lot of stress. If you have clay soil that is more likely to cause winter heaving, the situation may be different.

Garden Ho’s examples are all suckering shrubs, so that is the key as to whether you can divide it. Is there a single main stem on your Miss Kim with side branches off the main stem or are there many stems coming from the ground, ie suckers?

That may have helped my success, but I actually cut the rootball in half, with the exception of one of the Iteas as it had suckers off to the sides.

Fall is actually a recommended time for transplanting any woody plants as that is when the root system is in its most active period of growth. And this is really not location dependent. Woody plants - trees and shrubs - establish faster when planted in fall as the soil stays warm, temperatures are cool, roots continue to grow and elongate and there is usually plentiful rainfall.

I would also caution about trying to divide shrubs. They are not herbaceous perennials, never require dividing and unless you know what you are doing, you are more likely to kill the plant than successfully split it in two. I would take this approach even with caning or suckering shrubs (which the barberry is not, btw), although these may lend themslves to this practice easier than other shrub types.

when I moved my lime lights I moved the entire shrub in one large rootball..so heavy we put it in a yard wagon..husband pulled the wagon and I walked alongside to keep the shrub upright..they were replanted in shade (that's all I have!) which probably gave them less stress..just giving some info about the move since it was a success..

Well, it must be my particular part of the country that has fall planting trouble because nurseries aren't even selling plants, just putting the ones they still have on sale.

We have a lot of freeze thaw here, with no snow cover during much of the time when this is happening. Plants almost always heave out of the ground. Zone 5 NY is a really iffy zone with very variable temps and snow cover. I've lost too many fall planted plants so I stick with spring and don't mind a little extra care till they "take."

I also have problems winter sowing in containers due to too much variability in climate. They all die. So it's under lights or in/on the ground for me.

Different strokes for different folks. Best to ask someone local to you for advice.

I was planning to move them this weekend. But they have not start dropping leaves yet. Should I wait for the leaves are gone? Or does not matter? Thanks again!

I would do it now.

Thanks Bab.

I dug it out this morning. Cut the root ball to 2 parts with a electric chainsaw. (Did make sure there is no rocks in there before I use the chainsaw) I forgot to take pictures after the cut, now they are planted in my veg garden. Will report back in spring if they survive.

Prob will move the hydrangea next couple weeks when I get time.

Thanks

Winter, for dormant deciduous shrubs (bare-root quite often) and summer for evergreens.

I need to move a large Salvia melissodora. I think I will do it before deciduousness because I need to be worried about root rot. I think October in the slow wind down but still some good growth left in the season. It is rated as a Z 9 salvia being grown in a Z8 area. It has lived for a long time but it has lost its sun due to a tree that had the gall too grow. It has not bloomed worth a darn lately.

Camps, Rockdale is somewhere in New England, where one cannot dig in winter. :>\

So now, not long before leaf drop, with ample rain, shorter days, warm soil, and cool air temperatures is usually a very good time.

Cheers Babs - tend to forget stuff like snow and ice. But yep, in that case, I concur - do it now (this is my frantic busy season).

Its that rock hard frozen ground that hampers digging. One needs a blow torch to get through that stuff. I have not experienced it lately but it was a feature of my youth.

Two optimal times: In the early spring while they're dormant, or in the fall about a month or two before the ground freezes.