Mishnah 4 in the second chapter of Maseches Shevi'is also lists additional activities that are permitted until Rosh Hashanah, and all of them are performed on saplings. A netiah is a sapling, and as we saw earlier, the commentaries disagree about what qualifies as a sapling and for how long it retains that status; but whatever the measure of a sapling may be, the activities listed in the Mishnah are permitted with it.
The activities permitted with saplings:
"Mezahamin es hanetios" - several explanations are given here. Some explain that this refers to a sapling whose bark has been peeled off, and in order to heal it they would take manure and dung and cover the peeled area with it, to help it heal. Others explain that it refers to smearing foul smelling oil on the saplings, so that the worms that attack the trees would flee from the odor.
"Vechorchin osan" - wrapping the sapling in cloth, as was customary in order to protect the tree from the sun or from the cold. Some explain that it means gathering the branches and tying them upward.
"Vekotmin osan" - this can be explained in two ways: ketimah from the root meaning cutting, that is, trimming the tips of the branches; or from the word kitma, which means ash, for they would take ash and smear it on the roots of the tree in order to benefit it.
"Ve'osin lahem batim" - they would make small huts and little houses for the trees, in order to protect them, in the same manner mentioned above regarding "vechorchin osan."
"Umashkin osan" - watering too was permitted, but not in the usual way: they would pour the water on the top of the tree, and from there it would run down and fall to its base.
All of these activities are permitted "ad Rosh Hashanah" - that is, until the beginning of the Shemittah year.
The opinion of Rabbi Elazar bar Tzadok:
Rabbi Elazar bar Tzadok says "af mashkehu es hanof bashevi'is" - that even during Shemittah itself one may water the branches of the tree and its foliage, "aval lo es ha'ikar" - but not the trunk and not the roots, for it is forbidden to pour the water there. It was permitted only to pour the water onto the branches of the tree, from where it falls downward, and this is so even in the Shemittah year itself.
In summary: This Mishnah listed five activities permitted with saplings until Rosh Hashanah - smearing, wrapping, trimming, making houses and watering - and we examined the various explanations offered for each of them. According to Rabbi Elazar bar Tzadok, watering the foliage (but not the base) is permitted even during Shevi'is itself.