Trellises and supports during shemitah
Question
Is it permissible to train climbing plants onto a trellis during the shemitah year?
What about adding supports to trees that have begun to grow crooked? If so, under which conditions?
Answer
Training plants onto a trellis to enhance the plant is forbidden. However, it is permitted if the plant will die otherwise. As the rule of thumb: ukmei ilana, actions performed to keep trees alive are permitted, while avruyei ilana, actions to enhance the tree is forbidden.
Rabbi Yaakov Ariel maintains that if a plant was planted for a specific purpose, even if now it lost this purpose, to fix the plant so it fills this purpose again is considered ukmei ilana. For example: passionfruit planted to be a living fence that fell to the ground because of the wind. It is permissible to lift it a little and return it to the fence.
However, if a passionfruit vine that does not fully cover the fence and you want to move several branches so that it will cover the fence – this is prohibited.
A tree that is growing crooked – if you do not put up a support, the tree might not die, but it will also not fulfill its purpose, which is to stand straight and tall and provide shade. For this reason, it would be permissible to put supports for the tree.
However, for flowers or bushes – even if they grow crooked, they will still be the plants they were meant to be, it is forbidden to train them onto a trellis.
In conclusion: It is forbidden to move a plant so it will begin to climb onto a trellis, since it could continue to grow even without the trellis. Of course, it is forbidden to set up a new trellis during the shemitah year. All of this is true in cases where the flower or bush will be find on their own.