Over the course of the last year I have been watching two pistachio blocks very closely, both near McKittrick, CA. One grower chose to protect his newly planted pistachio rootstocks with paper tree guards, while the other used Wilson Grow Tubes.
I drive by the block with the paper tree guards on my way to the block with the grow tubes. I know for sure it was planted before the block with grow tubes, possibly quite a bit before (the grow tube block was planted in late May, 2011).
The comparison is stark. Take a look:
Pistachio rootstocks planted prior to May 2011 with paper tree guards. The growth rate is very inconsistent; some have been field budded and some haven't (or if they have the buds didn't take). Click to enlarge.
Failed field bud - this tree will have to be replanted.
Compare those shots with these:
Pistachio rootstocks planted late May, 2011. Field budded in August, 2011. Note the uniform growth and very high rate of budding success. Click to enlarge.
Grow tubes have been removed for reuse planting another block. The height and development of these pistachio trees grown in grow tubes is remarkable. The high rate of budding success is apparent; the broader leaves of the scion variety, as opposed to the long then leaflets of the rootstock variety, are obvious. Click to enlarge.
Which field would you rather have?