How would you pronounce the above Latin name?

Many years ago, I went into Annie's Annuals looking for this plant. I had trouble finding it, so I went to one of the workers there and asked her to show me to the a-gah-STASH. The worker stood there looking at me, clueless. Finally a lightbulb went off and she said 'Ah!' and took me to the appropriate section. I wondered about that for days. What had I said wrong?

Fast forward to this past spring, sitting in class at Merritt College. One of my teachers explains that Latin botanical names are usually (though not always, wouldn't you know it) pronounced with the stressor on the antepenultimate syllable. Hence the plant Pittosporum is pronounced pit-AH-spore-oom. I immediately flashed back to a-gah-STASH, and realized what I had said wrong all those years ago. I felt smug, and learn-ED.

Not long after, another professor bought the Agastache for the section of the garden I and my team were working on. "Oh!" I said to him, "I love a-GAH-stash-ay." That professor stood there looking at me like I was nuts. Finally he said, apologetically, "I say a-gah-STASH-ee." Well geez. So much for smug and learn-ED. I changed back to my original pronunciation and added his 'ee.' "NOW I've got it right!" I thought.

Flash-forward to this morning, as I was buying two of this very same plant for my yard in a reputable nursery near here. On the descriptive sign below there was a helpful pronunciation guide. Neatly typed, it cheerfully read, "Say: a-GAH-stah-kee!" For heaven's sake, I thought. Just how many pronunciations are there???

So I came home and looked it up on Fine Gardening's Pronunciation Guide. Wouldn't you know it? a-gah-STACK-ee.

I mean. Come ON.

So screw it. There is no right way to say these things. I'm sticking with whatever comes out of my mouth in the moment. I suggest you do the same.