Ask Mr. Smarty Plants

Unfortunately, we think you are trying to put the square peg in the round hole, or the non-native plant into the native dirt. At the Lady Bird Johnson Wildflower Center, we are dedicated to the care, protection and propagation of plants native not only to North America but to the area in which the plant is being grown. The native plant is adapted by millennia of experience to the soil, climate and rainfall of its own area, and will need less water, fertilizer and maintenance to survive.

For instance, your first plant choice, Tecoma stans (yellow trumpetbush), while it is native to North America and to Texas, is NOT native to, nor does it grow in, Smith County, according to this USDA Plant Profile.  The reasons for this are that it is basically a desert plant, liking rocky alkaline soils and limestone-based sandy soils. In East Texas, your wonderful acidic soils with thousands of years of leaves from deciduous trees contributing to that acidity and soil texture, the Esperanza is just out of place. This USDA Plant Profile of Chelone obliqua (red turtlehead) shows it native to North America, but not Texas. There is a native plant, Phlox paniculata (fall phlox) native to North America, and is 3 to 4 ft. tall, so that is probably the one. Alas, again, this plant is not native to Texas-USDA Plant Profile.

So, lets look at some of the other plants you are pining after:

Alstromeria - native to grasslands and pampas of Brazil

Japanese Iris, Iris ensata - native to northern China, Manchuria, Korea and Siberia

Plumbago auriculata- subtropical, native to South Africa

Shasta daisy, Leucanthum vulgare x superbum is native to Turkey, Russia and Europe

Shasta viburnum, Viburnum plicatum f. tomentosum 'Shasta' is native to China, Japan and Taiwan

You can Google on these Latin names and read about the conditions in which these plants grow, and try to envision how you would create that environment in Tyler. Or you can send us another question on how to find plants native to your area that will do well in the conditions you have described in your own garden, and we will be glad to help you out.