In Plots.jl, you could try the following code:
using Dates, Plots; plotlyjs()
start_date = DateTime(2021, 1, 1)
rr = rand(100,36)
xaxis = start_date:Dates.Month(1):start_date+Dates.Month(36)
DateTick = Dates.format.(xaxis, "yyyy-mm")
x = 1:length(xaxis)
yaxis = 15:115
heatmap(x, yaxis, rr, ticks=:native, xticks=(x,DateTick), xtickfontsize=5, xrot=45)
