Here's a list of plants that can't handle the South's heat and their Southern cousins that can.
Alien beings have moved in next door. My family is justifiably concerned. We know they're not from around here because of all the weird plants they've brought with them--lilac, paper birch, blue spruce, delphinium. Word has it our new neighbors come from a planet named Wisconsin.
Alien plants from the North look nice when first set out. But they usually can't hack the South's hot, humid summers and short, mild winters. So they either fail to bloom, fail to thrive, or simply croak. Why, then, do aliens keep trying?
For an answer, I consulted several admitted aliens. Kathy Foster, who grew up in the wintry worlds of Northern Kentucky and Ohio before moving to Fort Walton Beach, Florida, told me, "We try because we have pass-along plants from grandparents, family, friends, and deceased loved ones that we don't want to lose. These plants evoke pleasant memories." Other aliens said they just like to buck advice and plant something people living here say won't do. And if they succeed, native Southerners often copy them.
Of course, the ultimate fate of such plants depends largely on where in the South you live. Many of them do okay in the Upper South but struggle elsewhere. You could make them feel more at home by refrigerating the soil or dressing your kids in stripes and plaids, but this is a lot of trouble. It's easier to simply substitute plants better adapted to the South that possess similar qualities.
For example, you love lilac, the favorite plant of the planet Wisconsin, but you now live in New Orleans. Lilacs won't bloom in the Big Easy, due to the lack of winter chill. So, instead, plant chaste tree (Vitex agnus-castus). It has beautiful blue flowers like lilac, grows 15 to 20 feet tall, tolerates heat and drought, and resists pests. Or plant a crepe myrtle. Its flowers are just as striking as a lilac's. Crepe myrtle also features colorful autumn foliage and handsome winter bark where lilac is ornamental only when blooming.
Want a few more examples? Okay. Rather than planting the paper birch (Betula papyrifera) or European white birch (B. pendula) you remember from your home world, try 'Heritage' river birch (B. nigra 'Heritage'). Its bark is just as lovely, but it doesn't get the borers that plague the other two down here. Do rhododendrons wilt and die before your eyes? Substitute French hydrangea (Hydrangea macrophylla). It loves our climate and flaunts gorgeous flowers of blue, purple, pink, rose, or white for many more weeks than a rhodie does. Can't grow delphinium? Try larkspur. This reseeding annual gives you the same shape and flower colors, but it's much easier to grow. And instead of maintaining tuberous begonias on life support throughout the hot summer, grow the lovely and carefree angel-wing begonias. Lots of blooms, little fuss.
My new neighbors from Wisconsin desperately need this advice, but we don't know how to approach them. We saw them having brats and beer for breakfast, and we're very much afraid.