The carnations that florist use are a hybrid of Dianthus caryophyllus and a zone 7-10 plant. Humidity is the issue in Southeast Missouri and Northeast Arkansas more than the marginal hardiness of the plant. I have tried a cultivar called Dianthus caryophyllus ‘Grenadin series’ and had very little success with it in our clay soil (I live in Paragould Arkansas) and our humid summers. In fact, this is the first year we (Adams Nursery & Landscaping) have not grown it. Our customers were having too much difficulty with it. Unfortunately, I haven’t found a Dianthus caryophyllus that works well in our area. If you like to know more about carnations read Carnation A Classic Flower.

Oleander is a zone 8 to 11 plant. However, until they decided to cut them down a neighbor of mine had some beautiful Oleander. We carry a variety of Oleander called Cardinal Red. If you want to grow oleander and are worried about the hardiness of it, grow it in a pot that you can move to a protected area during the winter. I gave my mother one for Mother’s Day. I potted it in a pot that was big enough to support the plant yet my father could move. They are going to place it in their basement over the winter; the basement has a glass sliding door which should give the oleander sufficient light. It should flower all summer. Do keep in mind this plant is poisonous and small children and pets should be supervised when around it.

I hope this information helps.