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The only problem you may haveThe only problem you may have is too much shade from the tree. Sunflowers need as much sun as possible. Planting sweet peas close to sunflowers is a good idea. They may use the sunflower stalk to climb on.

2015 Special Edition Garden GuideCooking Fresh with The Old Farmer's AlmanacThe Almanac Monthly Digital MagazineWhat the heck is a Garden Hod?