In my view the choice of what ingredients to use in the mix should be based on how long the plant will be in the mix before it is changed out. If this tree will spend a few years in this mix then I would choose the gritty mix since only 1/3rd of the mix is subject to breaking down and holding more water at the expense of less oxygen. In the basic mix almost 90% is subject to breaking down. If water retention is your concern you can decrease the amount of grit and increase the amount of Turface. Grit holds no water, Turface holds a lot. I have some citrus trees growing in 1 part bark fines and 1 part turface and for my tastes it holds too much water. I have some more citrus coming this week and I already have their planters ready with the gritty mix. Years ago I was afraid of the gritty mix for the same reason you are, concerned I would be a watering slave. While you probably will be watering a bit more often than with a peat based mix, I think you will be surprised how much water the gritty mix holds, particularly in a large, deep container. When in doubt, just increase the turface while decreasing the grit.

There are no magic numbers or maximum height rules, it all depends on the what else it there, the size and shape of the entire planting, and the sizes and shapes of the rest of the plants. You don't say what kind of spruce, whether they are dwarf or large sizes. 25 large Spruces suggests a fairly large windbreak planting if you spaced them to allow for their mature size without too much overcrowding. In this case, I would say that using other plants in multiples of 3, 5 or 7, or more depending on how large they will get, will be necessary to have any impact. The smaller the individual shrub, the greater the quantity you should use, in general. I have Deutzia gracilis 'Nikko' in zigzagged groupings of eleven in one area and 13 in another. Oakleaf Hydrangea 5 in one area, 3 in another. Rhododendrom maximum, just one as the center of a planting with other shrubs. Plot the mature sizes of the spruces, and leave enough space between them and the new additions. It will look nekkid for a while, but with good care, will eventually fill in and look much better than if you overcrowded them early on. This applies if you used dwarf plants as well, just scale back your additional plantings in number and size to blend with the scale of the existing plantings when it matures a bit.

thanks for responses-as for my warranty I believe its long gone- pretty good nursery (selection, staff) but their warranty is horrible. but the owner did come down this spring and made good on one-so we'll see. I still believe its touch and go with these spruces. I do take good care of them-and believe I have done everything right so far-but still not sold on if they will all make it. Thanks for providing a direct link Pineresin. Actually the picture of tree2 looks better than it does in real life-maybe i can capture a better one again. It seems lime-green almost yellow-green-while all the others are a very dark green. I also believe the interior foliage could be better-it seems barren in spots-and these don't come back I take it? well at least my skyrockets are really taking off (no pun intended). I think the real test will come next spring- early summer- they will be on their 3rd year and i should be alot clearer how well they will do. Didn't know spruce were so picky to get growing and take- If I had known this I probably would have mixed it up with something else, but I am still a novice to all of this. thetman

John: A wondewrful plan--I am doing something almost exactly like what you are doing, except I am planting a larger grouping of both species, with a little more spacing in the middle. I think more people need to think of planting groups of compatible trees together. I agree your spacing is good, but if you are leaving open space on all sides of the group, they could be closer together, especially if the group were to be two or three instead of the four. If trees grow at about the same rate they could be very close together in pairs or threes. I don't know how large the trees are that you are planning to plant, but you may consider planting a few "extras" to make sure that you get individuals that are equally vigorous. Individual Norway spruce trees vary in growth rates, and some strains of white pine do better than others. In Western MD on the Allegheny Plateau in one place the State planted Norway spruce and white pine together, but they had a bad strain of white pine and it fell behind badly. So if you palnt extra trees as a back up, get them from different places or find out if you can get trees from separate seed sources. Another combination I like is Norway spruce and larch. There is an old historic home south of Leesburg, VA where this combination was planted--two Norway spruce, one European larch. I think one of the Norway spruce is in decline, so it may end up as a pair. They are very old--maybe 130 years or more--and they are really pretty in the corner of the old formal garden where they were planted. They were planted about 8 feet apart, if my memory is not fooling me now. Where you are, the hybrid Dunkeld larch may be best if you want to try this combo. --Spruce