Ask Mr. Smarty Plants

Both Malvaviscus arboreus var. drummondii (Turk's cap or turkscap) and Malvaviscus arboreus (Turkscap) are shown in their USDA Plant Profile Maps as being native to Denton County, right next to Collin County, so they are within their natural range. However, the same maps show that many of the areas where the Turkscaps grow are farther south, both in Texas and other southeastern states. This has been an unusually cold Winter and late Spring for Texas, especially in your area. We think they will be all right, as they seem to be tough native flowers, but we will poke around in Google and see if we can find any more information. You can follow those plant links above to our webpage on each plant to find out growing conditions, soils, sun and water needs and compare those with the garden where you are growing your Turkscaps.

From Texas A&M Aggie Horticulture on Turkscap:

"In the Valley it is evergreen, flowering year round, but farther north it will die to the ground as a herbaceous perennial in colder climates where it grows to a maximum of 4 by 4 feet."

"In North Central Texas' black clay, a well-established turk's cap is exceedingly difficult to dig up due to its very tough, dense and deep roots."

It is considered hardy to USDA Hardiness Zone 7. According to this USDA Plant Hardiness Map, Collin County is in Zone 7b, so you should be all right.