Q: Do I need more than one variety of pear tree in order for it to produce fruit?

Q. Which plants will attract hummingbirds to my garden?

A. Hummingbirds are among the many migratory species of birds that pass through the Chicago area in May, as they fly north, and then again in fall, as they fly south. To encourage these birds to visit your garden in both seasons, and possibly even nest there, you should plant the flowers that give them maximum nectar they can convert to energy. Since hummingbirds also eat insects, gardeners are advised not to spray their plants with insecticides.

Q: My children and I want to plant a butterfly garden. Can you suggest flowers that will attract butterflies?

Q. I would like to grow the beautiful butterfly bush that attracts so many varieties of butterflies at this time of year. Any tips?

Q. For several summers now, I have noticed plenty of bumblebees in my garden but very few honeybees. What is the reason?

Q. Why do apple trees drop their fruit early? We have an old apple tree on our property that produces pocked, rotten apples. Is there way we can help the tree produce edible fruit?

A. Some fruit trees will naturally thin themselves by dropping excess fruit prematurely. Often, a period of stress (a long, hot summer with very little rain) will cause a tree to abort its fruit in order to conserve energy. Apple trees require deep watering during drought. Lack of pollination can result in pea-size fruit that falls off prematurely.