It is wrong to count syllables in English.
Our first failure - when we tried to mimic our own Classic (romance language) poetry - should have taught us better centuries ago. English syllables are hopelessly irregular and, on average, half-again longer than the Japanese syllabet.
If we would strive for some uniformity in our haiku, we must utilize something that we do have: a good beat. Japanese beat is so weak that some say the syllabets are always equally stressed and / or identical in length. Our beat, if we would teach it (or, them), can even be recognized by children.
I noticed, independently of Blyth - that Japanese haiku, even when the syllabet count exceeds the ideal - usually have 7-8 beats; and, so, I think, should ours."