I would like to plant the Aravah in my backyard to use for Arba Minim. We live in New York. So climate should allow it. In a related question, you mention the Aravah tree is the Salix Alba. This is the white willow. I did some research about it. It grows 50 ft high. The problem is this is a huge tree and not meant for residential homes. It creates all kinds of problems for homes. Besides it needs a lot of water and my landscaper even said it would not survive. You find the Salix Alba close to rivers and lakes. Then I realized there is also the Willow shrub which is more like a bush and it looks like many use this for the Aravah. This would work as it only grows 5ft tall and does not need as much water as the Salix Alba. The question is which willow bush can be used for the Aravah to do the Mitzva of Arba Minim. I did some research about willow bushes and found the Salix purpurea - Dwarf Arctic Willow. I think this is also called Arctic Blue Leaf Willow. But I am not sure whether this is kosher for Arba Minim. According to the Sefer ?Halacha of the Four Species?, the signs of Kosher Aravah are a red stem, leaves shaped narrow and long, and leaves that have smooth edges. This Salix purpurea has a red stem and based on the look, it also fulfills the other two requirements. But the Sefer also mentions that if the willow does not grow nowhere near water, it can be kosher if it belongs to a variety that generally grows alongside brooks. I don?t know whether the Salix purpurea generally grows alongside brooks. I thought you maybe know the answer. I appreciate your help on this matter. Thank you very much.
ב"ה Shalom There is extensive discussion among contemporary Rabbis as to if the signs of a red stem, leaves shaped narrow and long, and leaves that have smooth edges are only once the tree is recognized by tradition as an "Arava" or if we can we rely on the 3 signs even if not considered an Arava botanically. However, this discussion is only in regard to an after the fact - a "Bedieved" - situation and all are in agreement that to begin with there should a tradition regarding the particular trees that can be used as an "arava". Therefore, it would not be enough to know if it grows by water since you want to plant an arava tree which is considered so by tradition. Therefore, I can only suggest that you should consult your local Rabbi as to if this particular willow is accepted by tradition. All the best