...when planting my emerald cedar shrubs and bloodgood Japanese maple. I go now to sin no more - I understand this is no longer accepted practice, notwithstanding the many sources where one can still find this outdated advice. Thing is, should I dig up what I've done and try and exchange what I added with some native soil? I also added bone meal to the bottom of the planting holes and covered it with about 1 inch of soil. I didn't disturb the bottom of the hole otherwise (so you see I didn't completely botch the job.) Other than the soil amendment (combo of humus-compost-peat moss) and the bone meal I didn't fertilize. I quartered the root balls with a knife to a depth of about 1/2 inch in order to disrupt any encircling roots, but I didn't try and tease the roots out, and I didn't try to take off any of the original soil from the root balls. Except for the maple, which is at ground level, I planted a little on the high side. I put a small sample of soil in a jar with some water and liquid laundry detergent, shook it up, and left it to settle. From what I can tell we have sandy soil (not too surprising in rocky Nova Scotia). I've since read that if I had to go and amend the planting holes, doing so in sandy soil is not as bad as clay soil (if by 'heavy' soil, one means clay soil.) I must say, I expected to make mistakes when setting out to garden but I didn't expect to excel so well at the process of making mistakes. Now, how does this sinner redeem herself (and hopefully see her shrubs and maple thrive)?
Just monitor moisture carefully, watching in particular for drying out next summer. If you have sandy soil they are probably unlikely to end up sitting in puddles. After they root into the native soil beyond the amended planting holes they will start growing as if they were planted directly into native soil. Be sure they are well mulched, do this with all plantings.
Thank you so much Ron for your fast reply. I will do my best to watch watering conditions, although this year was a doozy - good thing I didn't plant in the spring, when we had 300 mm of rain - about a foot! during the month of May, followed by a dry summer. Is it okay to mulch on top of the crown (I tried to leave the 3 inches or so around the trunk with as little covering of anything as possible.) Also, so that is the reason for avoiding amendments, that one risks having the plants sit in puddles? I was told (somewhere, sorry can't remember where) that it was because the plants would not want to root out of their overly comfy amended planting holes and into the less well nourished and often more compacted surrounds. Hence my alarm - that my plants wouldn't root out into the surrounding soil and thus would start to die after their 2nd or 3rd season. (Note: apologies if this is a repeat post)
Yes: you never want to bury the crown with mulch or soil. Yes: the now commonly stated idea that amending of planting holes is counterproductive because roots "prefer" amended planting holes, thus circle around within them is a bad argument for a good practice (skipping amendments). How amending affects movement of water into and out of small, liberally amended planting holes is the main problem with them. Plants that are sitting in a pocket of mud or dust do not establish as quickly; if conditions within the amended hole are bad enough they can even die.
Thank you again Ron. I think I'm starting to get the idea - planting is all about building infrastructure for air and water first: nutrients, fertilizer etc. are almost secondary. Not so unlike people I suppose - we can go a lot longer without food than we can without water, and a lot longer without either food or water than without air. It's a good thing that involuntary herbslaughter isn't a crime, because I think I'm going to turn up a few corpses before I'm done....
If a site has a soil with a serious nutrient deficiency that can really reduce growth response from plantings as well. Every situation where plant response is deemed inadequate will have a limiting factor or limiting factors that must be identified and addressed before growth will improve. Sampling and testing of soils (or foliage) are used to get an idea of what is going on.