Mother, tether is a verb as well as a noun, no apostrophe, don't know what word you might have in mind that has a dropped first syllable. Its use in your sentence is redundant, since tether and bind mean about the same thing, except that I think of tethering a horse or something that might try to get away, think bind works better for milkweed. By the way, there is an online dictionary at
http://www.webster.com .
Carol