wordpress contactform7 textarea cols and rows change in smaller screens
Even though this question is more than 5yrs old, it is still active regularly and like me many of us trying to get a clear answer to this question.
You can also type 10x for cols and x2 for rows, if you want to have only one attribute.
[textarea* your-message x3 class:form-control] <!-- only rows -->[textarea* your-message 10x class:form-control] <!-- only columns -->[textarea* your-message 10x3 class:form-control] <!-- both -->
In the documentaion http://contactform7.com/text-fields/#textarea
[textarea* message id:contact-message 10x2 placeholder "Your Message"]
The above will generate a textarea with cols="10" and rows="2"
<textarea name="message" cols="10" rows="2" class="wpcf7-form-control wpcf7-textarea wpcf7-validates-as-required" id="contact-message" aria-required="true" aria-invalid="false" placeholder="Your Message"></textarea>
I was able to get this work. I added the following to my custom CSS:
.wpcf7-form textarea{ width: 100% !important; height:50px;}