I just noticed several clusters of red "quills" which sort of look like small buds on the main trunk and the two largest lower branches on my weeping willow tree. The little growths are red and barely 1/4 inch long. The tree appears to be healthy.
These look like adventitious roots, and the production of these in Willows is quite common, in particular if they are planted in a riparian setting (meaning near water). Sometimes the roots continue to grow outward and down, and will anchor themselves in the soil. They are also sometimes produced when conditions have not been advantageous, in other words, the tree is a little stressed and so puts out these roots to head off and seek whatever it is the tree requires, often just more water, though this production does not necessarily mean your tree is stressed.