title: Is it possible to add a grouping label to a corrplot?
body: <p>Is it possible to add a label that applies to a few variables in a corrplot? <a href="https://imgur.com/a/PwzRQNN" rel="nofollow noreferrer">This</a> is an example of what I'm after. In that case it is the word &quot;Petals&quot; on the y-axis.</p>
  <p>Below is the code to make the rest of the plot.</p>
  <pre><code>library(corrplot)
  
  library(Hmisc)
  
  iris_c &lt;- iris[, c(1:4)]
  
  test &lt;- rcorr(as.matrix(iris_c))
  
  corrplot(test$r, type=&quot;lower&quot;, order= &quot;original&quot;, 
           p.mat = test$P, sig.level = 0.01, insig = &quot;blank&quot;,
           col= colorRampPalette(c(&quot;blue&quot;,&quot;white&quot;, &quot;red&quot;))(100), tl.col = 'black', cl.ratio = 0.8, tl.srt = 45,  diag = FALSE, method = &quot;square&quot;)
  </code></pre>