Answer: Most weeping willows are grafted so look for a swelling on the trunk near the canopy of the tree. If there is no graft, your tree is a standard willow. It's possible that it was grafted at one time but the graft didn't take and the standard branches took over. If you see the graft and the branches are emerging from above the graft they may need to grow a little longer before they begin to droop. You can coax them into a drooping habit by making slings out of strings to hold stones or small rocks and hanging them from the ends of the branches. As the branches mature they should droop on their own.
If you cannot find a graft and you really want a weeping willow, you may want to take the plant back and have it replaced.
Best wishes with your weeping willow.
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