Q: I have a couple of watermelon vines that have melons on them. I need to know how to tell when they are ready to pick. They don’t sound hollow yet. Julie B., email

A: One way to determine if a watermelon is ripe is to look for the curly pigtail that grows across from the fruit on the main vine. If it’s green, the melon is not ripe. When it’s white or yellow, the fruit is ripening. When it’s brown, put the watermelon in the icebox and invite your neighbors for a weekend get-together.

Q: I ordered some Pink Lemonade blueberry plants but discovered that they cannot be shipped into Georgia because we have a statewide quarantine due to blueberry scorch virus. I shipped them to a friend in Tennessee. Is there a specific length of time I can keep them quarantined with her and watch for signs of scorch virus before bringing them here? Julie Gabler, email

A: Blueberries are the No. 1 fruit crop in Georgia, so it makes sense that we’d try to protect the plants from imported disease. Blueberry scorch virus devastates blueberries. Any company that wishes to ship plants into Georgia is required to test for blueberry scorch virus. Transmission can occur from early May through early August. Once a plant is infected, symptoms may take one to two years or more to develop. This makes early detection vital for controlling the disease. ‘Pink Lemonade’ is a garden novelty due to the pink color of the fruit, but the pink berries likely wouldn’t be the best-tasting blueberries you ever had. Knowing how much is at stake, I’d let your friend have them and buy one of the new varieties listed at bit.ly/GAbluenew.

Q: For the last few summers, I’ve been fighting microstegium (Japanese stiltgrass) at our home. It grows in patches, takes hold randomly and spreads voraciously. I spray with a high concentration of vinegar frequently. But I’m losing the fight as more patches pop up and overwhelm the natives. Matt Owens, Gainesville

A: The vinegar may kill the plant but the stiltgrass has probably dropped hundreds of seeds before it succumbs. You have to prevent seed germination to have any hope of control. Preemergent chemicals like dithiopyr, pendimethalin or prodiamine will prevent microstegium seeds from germinating. Since seeds germinate throughout the summer, two applications (mid-February and early May) are appropriate. For a heavy infestation, a third application in July might be warranted. Read and follow label instructions.

Email Walter at georgiagardener@yahoo.com. Listen to his occasional garden comments on “Green and Growing with Ashley Frasca” Saturday mornings on 95.5 WSB. Visit his website, www.walterreeves.com, or join his Facebook Page at bit.ly/georgiagardener, for his latest tips.