Hokku — which is much older than haiku (haiku only began in the late 19th century) — has very definite principles and standards. We do not use the term juxtaposition, so the closer one gets to hokku, the less one needs to think about that.

Instead, we speak of unity and harmony in a verse, which means it is not a random assemblage of things, but rather the joining of elements that are harmonious and unified when combined. That is what makes for successful hokku. One learns hokku partly by becoming familiar with the common types, among them the “standard hokku” form of setting, subject, and action that I mentioned in my previous comment.

But modern haiku has no universally-accepted standards, so you will be told sometimes one thing, sometimes another, depending on whom you ask.

And because this site is about haiku, I try to be careful to only comment when it touches in some way on hokku, as these particular verses happen to do. I neither teach nor practice haiku, so I cannot advise about that.