Answer: Some varieties of sweet potatoes will bloom, but this has nothing to do with them being ready for harvest. They may be harvested at any time once the roots reach a size that is acceptable to you. The ground usually will heave up and crack open at the plant's base as the roots grow in size. Most gardeners leave them in the ground until just before the first frost to get the roots as large as possible. However, if you planted them plenty early it is possible for them to get too large to suit your needs.
Therefore, I would suggest gently pulling the soil back from around the base of the plant for a few inches deep to check on the progress of the potatoes. Or, you could dig a hill in early September to see if the general size is large enough to keep digging! Good luck with those sweet potatoes!
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