Late blooms on hydrangeas caused by winter cold

Credit: Walter Reeves

Credit: Walter Reeves

Q: My blue hydrangeas are just now blooming — only four to five blooms. When should I prune, as obviously their schedule is off? They have not been pruned or fertilized this year at all, but the green foliage is healthy. Nancy Martin, Marietta

A: I think the hydrangeas’ schedule is right. You see, the beautiful blue hydrangeas you normally spot blooming around town each May are genetically programed to bloom at the tips of twigs that grew the previous year. Normally, your own hydrangeas should have bloomed in May 2023 on twigs that grew in 2022.

But remember what happened last Christmas? The severe cold froze all of your 2022 hydrangea twigs, leaving you with lots of healthy green foliage, which sprouted from the lower, unfrozen part of the plant. Those leafy green branches sprouted small twigs and the twigs grew flower buds at their tips. And the flower buds had enough time to mature and — voila! — you have unexpected blooms in October! Barring severe cold this winter, your shrubs will bloom normally next year. And, of course, don’t prune them either.

Q: I planted a small start of lemon grass in June. It is now over 4 feet high! Can you give me advice on when and how short to trim lemon grass? Sally, Atlanta

A: Lemon grass, Cymbopogon citratus, is an essential part of Thai and other Southeast Asian cuisine, with an immediately recognizable taste. However, unless you bring it indoors for the winter, your lemon grass will freeze in North Georgia. But you can split your outdoor clump any time before frost and put it in a pot for indoor culture. Put it in the brightest window you have. In South Georgia, where it can be grown outdoors year-round, lemon grass is pruned in January-March, which is fine for your indoor plants. Depending on the initial height of the clump, prune to between 4 inches and 12 inches high. Plant it outdoors once again in May, when night temperatures approach 70 degrees.

Q: I have zoysia grass and have had success with sprinkling water over the spot where my dog urinates to keep it from killing the grass. Once the grass goes dormant, will urine kill the crown and roots? Should I continue to sprinkle the spot with water? Pete Dawkins, Dunwoody

A: Sprinkling water onto the leaves on which the dog has sprinkled is a good idea because it dilutes harmful nitrogen salts in urine. But when the leaves are brown, the crown and roots are still susceptible. Continue to keep the watering can handy.

Email Walter at Listen to his occasional garden comments on “Green and Growing with Ashley Frasca” Saturday mornings on 95.5 WSB. Visit his website,, or join his Facebook page at for his latest tips.

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