This suggestion is taken directly from Sandra Gluth's wonderful newsletter to which I subscribe and would recommend for you. It is called Worthwhile Websites for Learning. All of her past websites from the newsletters are on this website. Go to Site of The Week Tab at the top to sign up to get the newsletter weekly. It is very worthwhile. Now on to this week's site that would fit into any unit on plants:
In Pollen Park, children join Bumbles the playful honey bee, on a pollen-collecting mission by completing activities and making amazing discoveries about plant reproduction. Students will learn the names of the different parts of the flower and understand the function of each in the reproduction process, the process of pollination and the varied methods of pollen transfer, the process of fertilization and how this differs from pollination, different methods of seed dispersal and why this needs to occur, and the process of seed germination and the necessary conditions for it to occur.