Rotate labels in Treemap

I am using RStudio to build a simple Treemap. The issue I have is that when the map builds one of the groups is very narrow, therefore the label is very small and hard to read. I thought a 'simple' fix would be to just rotate the label. But I can't find a way to do this. Is there a work around?

Here is my code:

treemap(data2C,
        #data
        index="label",
        vSize="Number",
        type="index",
                
        # Main
        title="",
        
        # Borders:
        border.col=c("white"),             
        border.lwds=1,                         
        
        # Labels
        fontsize.labels=10,
        fontcolor.labels="white",
        fontface.labels=1,
        overlap.labels=0.5,
        inflate.labels=T)

Here is what the output:
enter image description here

Thanks in advance for any help

You can rotate a label using ggplot2 and treemapify based on the proportion to thee maximum giveen value in the plot. This example rotates the label by 90 degrees when it's less than 5% of the maximum value.

library(treemapify)
library(ggplot2)

# Sample data
data2C <- data.frame(
    label = c("Group A", "Group B", "Group C", "Group D", "Group E", "Group F", "Group G", "Group H", "Group I"),
    Number = c(40, 50, 30, 40, 60, 20, 30, 11, 1)
)

# Build treemap
tm <- ggplot(data2C, aes(area = Number, fill = label, label = label)) +
    geom_treemap(color = "white", size = 1) +  # Add white borders to rectangles
    geom_treemap_text(color = "white", size = 10, angle = ifelse(data2C$Number / max(data2C$Number) > 0.05, 0, 90)) +  # Set rotation for labels and change text color to white
    theme(legend.position = "none")  # Remove legend

# Plot the treemap
plot(tm)

Output:

You might have to adjust the value 0.05 in

angle = ifelse(data2C$Number / max(data2C$Number) > 0.05, 0, 90)

based on your dataset to make it work as you want.

If you know the exact datapoint you want thee label to be rotated for, you can also replace the geom_treemap_text with this:

geom_treemap_text(color = "white", size = 10, angle = c(0, 0, 0, 0, 0, 0, 0, 0, 90)) # Explicitly set "Group I" to be rotated by 90 deegrees