I have the same question, just planted one of my two new JM's and am wondering how much to water. I read somewhere that watering should be consistent and should never overwater or water on extra hot days. They also said I could mist the leaves on extra hot days to prevent leaf burn. Does this seem accurate? I've thought about just lightly watering every 2 or 3 days for a week or two but want to do it right.

These are VERY hard questions since there are so many variables...how big the plant and root ball is , is the soil amended , how well does the soil drain,is it on a flat or hill surface, how hot it is and for how long...really anyone who gives you a "water this way advise" with waht you have posted is a bit presumtious.And a newly planted tree must not dry out totally but doesn't generally like to stay wet whereas an older established tree even one year in the ground should not need much wateruing except in the hotest dryest of periods at least mine don't. Since we don't know where either of you live I would suggest seeking out a nursery that carries JM's in your area and get their advise or state your exact location with all the above parameters and someone here from your area should be more educated to answer you with some semblance of accuracy ..David

I'll seek the advice, but for now...:
-Plant is 6'6" tall, 1.5" caliper stem, root ball is about 15" circumference and about 6" deep
-It's on a fairly flat surface about 1-2" above the surrounding grade though
-For a 10' radius around the tree, I rototilled the heavy clay soils with fresh compost so it should be fairly nice soil
-I live just northwest of NYC so Zone 6, gets hot in the summer months, but temperate in the spring/fall

Any tips now?

I think you are worrying too much about the watering issue. First, I don't think Japanese maples have water requirements much different from any transplanted tree, or other kind of garden plant.

Constantly sopping wet is not good, but you should not let the surface of the soil stay dry for very long, if at all. And the heat of the day should not make too much difference--if the soil is a kind that absorbs and holds water reasonably well at all, a good watering should last at least two or three days, and possibly/probably longer. Of course if it is hot and doesn't rain, you have to be more careful to keep the soil moisture at a reasonable level. Don't let your fear of a hot dry day cause you to overwater.

You can check the moisture of the soil by putting your finger down under the mulch and see if it feels cool and wet. If yes, wait before watering again. If it seems barely wet or dry, water.

One special warning however--there is probably a significant difference between the water holding capacity of the soil in the pot/root ball and that in the soil you are planting in. You should try to keep both moist (not soping wet). So when you check the moisture in the soil, check both soils.

Sometines the soil in the root ball/pot is a light soil that doesn't hold moisture well, and if that dries out when the tree in newly planted and does not have its roots established in the surrounding soil, the tree can wilt. Not good!

--Spruce

Heavy clay doesn't drain well obviously but amended it may be alright remember the water may pond in the clay beneath the amended soil so be careful...compost isn't the best way to go cause JM's don't like alot of N but thats ok... I would mulch ( I use shredded cedar mulch it's bug resistant)about 2-3or4" deep about 6-8" away from trunk water well when palnting then maybe about once a week keep an eye on it if it stays wet under the mulch you may not need to water much don't over do it It most likely will stay moist with mulch it is a true water saver and work saver .. a couple cubic feet of good mulch is worth much more than it's cost without it you will have to do alot more work and use much more water and hassle and take more chances with your tree... "respect the mulch"..in hot weather you may have to water more but you are in similar clinmate as I although I have rich black dirt ( but it also doesn't drain well since I am really flat and the soil is heavy but thats what I do) ...if it rains once a week you may not need to water ...It was really hot last summer and I think I watered my newly planted JM's maybe two or three times at most ...the mulch really holds in the water and my trees in the ground for a year only once...and then it rained 2-3 inches in a couple of days and some of thoase older trees didn't look great so BE CAREFUL...only fertilize in spring before or at bud break or early in leafing with low N fertilizer .Hope that helps...this is info for you others nmay be differnt and others here may have differnt opinions I am not the most knowledgable here but for what it's worth thats my humble opinion GOOD LUCK ...David

Thanks a ton, I think I'll just let nature take its course at this point.

You are scaring me with the compost comment though. I spent the past 3 days loading my trunk twice each day with compost to mix in about 2 inches into my clay 10' radius circle (jap. maple @ the center)....should I not do it? It will help loosen the soil up a lot since I have the heavy clay...by the time the maple's roots get out into the compost, a lot of the nitrogen may have leeched away anyway?

And 2nd question....I will mulch starting 6-8" away from the trunk, but I was going to also put down landscape fabric about 2' away from the trunk covering my entire circle, then putting the mulch on top...is this ok? I just don't want any of the grass I rototilled in that circle to start peeking through all the mulch and give me headaches....

Tnx again for the watering tips.

I have very heavy clay also and decided to till in "Soil Conditioner" instead of compost, etc.. because of JM's liking 'average' soil. The soil conditioner is mostly very small and extra decomposed pine bark pieces mixed in with a little sand. I think I ended up mixing in about 1 part soil conditioner to 2 parts heavy clay. The result is a more loamy mixture of soil that is essentially the same richness of soil. Seems to work well so far, but my tree has only been in the ground a few days.

Btw, here is a picture of where the maple was previously (you can see why I moved it, what were the previous owners THINKING!):
http://img243.imageshack.us/img243/9157/img0317tj1.jpg

And here is the area where I moved it to (gives the sango kaku room to grow the supposedly 20-25 ft. high and 15-20 ft. wide).

You can see the compost pile I am going to rototill into the big circle area surrounding the maple (again though, comments on my 2 questions in my previous post would be MUCH appreciated, especially since I'd like to finish it all today before it rains the next 3 days).

You can also see the old spot it was located in the top-right corner of the first image between the 2 windows on the lower level (replaced it with some iris's for now).

http://img180.imageshack.us/img180/8602/japmaplemoved1gd0.jpg
http://img404.imageshack.us/img404/2503/japmaplemoved2rt7.jpg
http://img263.imageshack.us/img263/2002/japmaplemoved3nk7.jpg
http://img404.imageshack.us/img404/8700/japmaplemoved4dq1.jpg
http://img404.imageshack.us/img404/3807/japmaplemoved5kl1.jpg

I 'd do spup's method and keep the compost for your garden but that was alot of work it most likely won't hurt but I'd probably not do it too close to the tree..if you plan on doing plantings of other stuff aounnd it I'd say go for it just keep it a bit away ..JM's are pretty durable and we JM'rs are probably too picky it most likely won't hurt it.

As far as the landscape fabric I use it alot and many of my jm's have it sorrounding them maybe 12-24" out from trunk.I mulch on top since that stuff is ugly and the heat reflected from the black is not good for any plants. Be advised that creeping charley and other stuff can and will grow on top of the mulch that is on top of the fabric especially if you have an area nearby that has weeds best to brick it off or it will flow in to the landscaped fabric mulched area ...just has been my experience...but yes the fabric is A-OK IMHO ..David

Thank you thank you! I'll just add in the compost, some websites selling maples online recommend it so I'm sure it won't really be all that bad.

I bought commercial grade gray fabric (used it on a diff. area last year and no problems), but it'll be plenty covered with my pine bark nuggets.

Good idea on bricking off the back area behind the maple because I have English Ivy there (although it pulls up fairly easily), no creeping charlie luckily. It'll be nice when it's all done! Thanks for all the help folks! I'll post 1 more pic when it's all done

Ok, maple is moved, planted, compost has been spread, landscape fabric put on, border edging put in, and pine bark nugget mulch added. Here is the final couple of pics (so far, looks to be doing just fine):

Compost rototilled into soil:
http://img250.imageshack.us/img250/7308/japmaplemoved06wa9.jpg

Landscape fabric added:
http://img293.imageshack.us/img293/4390/japmaplemoved07ip2.jpg

Pine bark nuggets added (project complete):
http://img388.imageshack.us/img388/6575/japmaplemoved09en6.jpg
http://img388.imageshack.us/img388/9471/japmaplemoved11aj5.jpg