I had to move some L. munstead too this year and I did that in March before new growth began. I would either move yours in mid fall with plenty of time before first hard frost when the weather is not so hot or next early spring.

Vera

Thanks Vera. I was worried about the timing of the move and if they had deep roots that would not survive the move. I also need to know if I can prune them back hard. Because of the wall they're near one side of each plant is
sort of flat and bald on the wall side. All sides will be exposed in their new location. What to do...What to do?

take some cuttings. even if your moving them take cuttings, its always good to take cuttings.

but seriously, if you plan to move them take some cuttings, and remember to reomve any flowers or flower buds on the cuttinng as flowers reduce the production of foliageroots etc.

that way if you move them and some die you have some small plants from the cuttings to take their places.

as lavender is mint family but with woody stems it will take to cuttings well as far as i know
you don't realy need homone rooting powder for sage or rosemary, or lavender as far as i know.

With lavender i would always use rooting powder. It does not root like mint.

Moving lavender is very hard. Make sure it is not in bloom cut the plant back and dont disturb the roots. TAKE EVERYTING! If you want to transplant and move it via car, clippings would be your best bet. You also get a new plant when you clip. Lavender only lives so long. Or just go out and buy new lavender (if you dont want to do clippings)

Thanks for asking this question, Pearly, as I have been pondering the same thing. I planted some lavender too close together (Grosso, of all things, huge) and I'd like to move a few plants. I think fall would be best, when the weather cools down.
I agree with Dr. Sassafras in that established lavender does NOT like to be moved. I gingerly transplanted some Goodwin Creek Grey and lost them. I think once the roots are established, lavender likes to stay where it's at.
I've had great success rooting lavender from cuttings in small, clear glass "rooting" vases and plain water. Old clear salt shakers work well too.

Take a cutting approx. 4-6 inches long, preferably after the plant is done flowering. Remove any leaves that would be below the water line (they will rot),add water and put the container indoors in a bright place near a window, but out of direct sunlight. You will see new roots appear in about 2 weeks.
After the roots are approx. several inches long, move the little darling into a small pot with soilless medium and let it grow a bit.

When the plant is about as large as the ones they sell at the garden center in the spring, plant it outside.
You can always buy new plants if you don't want to fool with this. But by taking cuttings, you can be absolutely sure of the lavender you are planting. I bought some plants last spring labeled "Munstead" that turned out to be Spanish lavender, which is not useful to make potpourri.

Good luck!

Yes, take cuttings! :o) I have had nice results from taking cuttings, dipping them in rooting hormone and keeping them in perlite which holds just enough water, nicely.... then I have an empty fishtank that I have a wee bit water on the bottom and covered for humidity.... works great. And if more than one strikes, well, you can't have too much lavender! :o)

DrSassafras

How do you use rooting powder with a large transplant. I have some, the small powdered bottle (indole butyric acid). I did large transplants today (no choice since I had to fix a sprinkler line break) and I thought of doing this but I had no idea how. I've only used rooting powder to dip a cutting in. Do you sprinkle it in the hole? If so how much? Can you water it in, what conc.?

Thanks