They are not difficult to make really. You barely need a pattern. With St. Patrick's coming soon, I was doodling and here is three ways to make a simple, small clover.
The stitch count is the same for all of them: chains are 15ds and rings are 7-7.
The first one is the simplest (first one being the bottom one in the picture above) and can be made with one shuttle and ball. Tat three 7-7 rings with just a bit of bare thread between the rings (a couple of millimetres), then reverse work and tat C15, join to tip of ring, C15, join to bare thread between rings, and so on. Join back at beginning and make tail, this one is made with Victorian Sets (3-3).
For the next one, I wasn't sure I liked the open space in the centre of the shamrock. So I started with a SCMR this time. You need two shuttles wound ctm. SCMR1, R7-7, 1-1, R7-7, 1-1, R7-7, 1, close SCMR. C15 and join to tip of ring, C15, join to small picot, etc. Join back at beginning and make tail (this one is made with a lock chain).
And for this last one, I decided to reverse the rings. Chains could be a tad shorter so that the leaf is a bit less heart-shaped if desired. R1-1-1-1-1-1(5 tiny picots), C15, R7+7(to small picot of centre ring), C15, join to next tiny picot, repeat all the way around. Join back at beginning and make tail as before.