What varieties of red stemmed rhubarb grow best in southern Harford County and when is best time to plant. I tried a few years ago with a large tuber of variety Crimson Red planted in early spring in a sunny area. It did well until the real hot weather hit in August and then it died back and never came up again.
Here is our rhubarb info: https://extension.umd.edu/learn/featured-plants-rhubarb
We recommend Cherry Red, Valentine, and Victoria. https://extension.umd.edu/sites/extension.umd.edu/files/_docs/programs/hgic/HGIC_Pubs/Edibles/HG70_R...
Be sure to water well for at least 2 years after planting so that roots can get established. After that it is more drought tolerant.