(written a while ago, worth repeating here)
A quickie note on goldenrod, because it's allergy season:
Goldenrod is not responsible for airborne allergy attacks. The pollen from goldenrod is heavy; it does not fly on the wind. It has to be pollenated by bees moving around. Therefore, it doesn't get into the air and it doesn't make you sneeze.
However, it does bloom at the same time that ragweed does, which IS airborne, and does make you sneeze, and is generally foul.
Why do I know this? Some 20 years ago, I had a short, round, elderly professor for Plant Bio II, who got very...exercized...about the poor, demonized goldenrod, and once expounded for a good 20 minutes at 180 decibels, jumping up and down for emphasis, about how goldenrod could not, would not, push allergens into the air.
So on behalf of my longago professor, don't blame the goldenrod. It's a case of mistaken allergen identity. :)