I planted my bushes in soil amended for vege gardening (oops #1) where they get up to 9 hours summer sun (maybe oops #2). They are 4 years old and are under 2 feet tall. Yes, they were labeled as high-bush, not low-bush varieties, york and legacy.
The house behind us has several bushes, that are prolific, but the neighbors sold out before I planted mine, so I can't collaborate with them. Theirs are shaded, resulting in more like 6 hours of sun, but planted in the open, not as an understory.I thought to move them to less sun. I'm new to permaculture, and don't know which area might have the right nutrients. I have spots near pine (heavy shade all day, probably a baaad choice), oak (dappled to partial P.M. sun), cottonwood (part A.M. shade), elm (part P.M. shade), or maple (part P.M. shade). The whole place is heavy clay, acidic down to the well water, so next to the pines should not be necessary. Each location does drain well.
Perhaps I have permanently dwarfed these plants and should start over?
Blueberrys love acidic soil. bit if it's mainly clay their roots will have a hard time spreading which will dwarf your bushes. You need to keep that acidity in the soil and get more organic matter in there to loosen it up so the roots can spread more.
Location: Officially Zone 7b, according to personal obsevations I live in 7a, SW Tennessee
"The whole place is heavy clay, acidic down to the well water..."
Acidic is taken care of. The ground near each tree is more friable than in the turf. Although the garden soil is looser than near the trees., more alkaline due to lime treatments. I can add a small amount of compost. I don't have much. Perhaps 5 gallons to split 3 ways. I do have some mostly composted horse manure, nothing 'younger' than 4 months aged. Would this burn them, or is it okay?
Other than acidic, which is taken care of, which tree might provide for blueberry? I also have a tulip poplar (A.M. sun, PM full shade, or A.M. full shade, P.M. full sun)
My question is in the context of this, paraphrased. Morels are frequently found on the downward slope underneath tulip poplar...
generally you should avoid adding organic matter to planting holes. As it breaks down the soil sinks and roots can become exposed. You can also end up, especially in heavy clay soil, with plants getting water logged as they are essentially planted in a "pot" of improved soil surrounded by clay that doesn't drain.
I would try adding a deep layer of wood chip to the surface of the surrounding soil and let the earthworms and the like work it. Areas where I have done similar in our garden have dramatically improved organic matter content in the soil 12 months later down to a depth of about 12 inches (we have less clay than you though).
Moderator, Treatment Free Beekeepers group on Facebook.
It sounds like your soil is going to need some long term TLC if you want to leave the bushes where they are. To that end Michael has given wonderful insight and suggestions.
Blueberries do fine in full sun, ours receive full sun from 7:30 am to 7:30 pm, they do not show any signs of heat stress or sun burn, so don't worry about leaf burn unless you get water on them during the strong sun period.
I would follow the advice Michael gave about mulching with wood chips probably to a depth of 6", be sure to keep the mulch away from the trunks, you don't want to create a problem with those staying wet.
If you decide to add more bushes, do a year long soil amendment before you plant the new bushes. I would mark out the area for the new bushes and amend the entire area with chopped straw, wood chips, leaf mold, and any compost I could spare.
I would repeat this addition of amendments every month for that year before putting in the new bushes. Since you have acidic soil (blueberries like a pH of 5.5) you most likely won't have to do any acidification. I would however test the pH just to have a solid knowledge of just how acidic your land is.
If you need to you can always use vermiculite as one of your amendments, it will help clay soils by sucking up some of the soil's excess moisture and open it up some at the same time. That will help the other amendments have more of their desired effect.
Blueberries have shallow roots (never dig around an established bush deeper than two inches) which don't have hair roots, so anything you can spread on top of the soil will leach right into the root zone with each deep watering.
Do not Fertilize new bushes their first year in the ground. In the second year use a little fertilizer at fruit set, then again after they go dormant for the winter. This second feeding is like Brylcreem...A little Dab will do Ya.
Worms, again as Michael spoke about, are going to be your blueberries best friends, they will pull organic material into the soil and create lots of channels which will be of great benefit to the root systems of your bushes.