Q: I have trouble growing alliums in Atlanta. If they come up, then they don’t come back the next year. Am I planting the wrong varieties ?Lynda Houser, email

A: As easily as wild onion, Allium canadense, grows in lawns, you'd imagine that any member of this genus would grow well in Georgia. I have planted several species and varieties of ornamental onion over the years, but most did not succeed. The one I had the most hope for, Allium christophii, did great, with huge blooms, for a couple of years and then petered out. My friend Erica Glasener says she has had the best success with 'Millenium' ornamental allium.

Q: Our blueberry bushes are 10 years old. This year, a good many of the green berries are falling off if you lightly touch them while picking the ripe ones. Any ideas?Nora Singley, McDonough

A: The most common cause of premature berry drop is poor pollination. Try to remember whether you had heavy rains during blueberry bloom time. Rain could have inhibited insect pollinators and might have damaged individual flowers. Without pollination, young berries don't mature.

Q: When do we trim blackberry bushes that have finished bearing? Ours have several really tall green canes. They are so heavy they are leaning over.Carol Brown, Twiggs County

A: You should prune blackberries a few weeks after harvest. This will give you enough time to note the new canes that emerge to replace the canes that fruited. Canes that had fruit will not bear again, and can be cut back to the ground. The replacement canes can be shortened as needed to fit your trellis. I recommend you cut your tall canes back to a reasonable picking height so they can grow side shoots during the summer.

Q: Can a rainbow eucalyptus tree survive in South Georgia? I love the tree.Kathy Sistrunk, Albany

A: The amazing multicolored bark of this tree, Eucalyptus deglupta, is certainly eye-catching! The weather may be hot in southern Georgia, but this eucalyptus likes it even hotter. Miami and farther south are good places to grow it. If you are interested in eucalyptus trees that are more cold hardy, check out Southern Eucs (southerneucs.com).

Q: I tested my pH with an inexpensive tester, and it looks to be between 7 and 8. What type of grass sod would do well in this pH? I get mostly sun and partial shade in a corner.Scott Ellsworth, email

A: The pH test kits you buy from garden centers are not very accurate. I doubt it says on the package what the accuracy range is, but I bet it would be plus or minus 1 point. In other words, the pH really could be anywhere between 6.5 and 8.5. Most grasses grow fine in soil with a pH of 6.0 to 7.5. I don't think you need to worry about your pH. In mixed sunshine and light shade, zoysia grass does very well.

Listen to Walter Reeves’ segments at 6:35 a.m. on “Green and Growing with Ashley Frasca” Saturday mornings on 95.5 WSB. Visit his website, www.walterreeves.com, follow him on Twitter @walterreeves, on Pinterest, or join his Facebook Fan Page at bit.ly/georgiagardener for more garden tips.