There’s a reason very few golfers can hit long irons effectively – a lack of clubhead speed.
The 2-, 3- and 4-irons have long shafts and very little loft. That means the club must be traveling pretty fast in order to bend the shaft and compress the ball against the clubface, delivering sufficient height and spin to stay airborne.
Of course, you’ve probably replaced your long irons with hybrid clubs by now. If so, you may still struggle to hit your longest remaining iron as far and high as you’d like. Again, too little clubhead speed may be the culprit.
Let’s say your longest iron is a 5. Compare your carry distance (not including roll) with the 5-iron to your 7-iron. You should see 20-30 yards of difference between the two clubs. If there’s less than 15 yards of difference, consider chucking the 5 and replacing it with an equivalent hybrid.
Another option is to change the shafts in your longer irons. A lighter model, perhaps a graphite shaft, will boost your clubhead speed. It’s also possible your current shafts are too stiff. Try dropping from an “S” flex (stiff) to an “R” (regular), or from an “R” to an “A” (senior). This will allow you to better bend the shaft on the downswing, unloading more power into the ball.
These videos will help you understand the nuances of shaft selection: