Prune Your Mugo Pine

My wife and I spent 5 months riding around New Zealand in the late 80's pre-kids, pre-marriage...on our bicycles.  During a memorable one-day backcountry ride (that took 3 grueling days) through mountainous sheep country, we were told to look out for "woolies".  These were sheep-gone-feral that hadn't been herded in for shearing in some time.  

Mugo pines that have missed their regular shearing remind me of "Woolies".  Pinus mugo, Mountain Pine is a high-elevation pine native to European mountain ranges (Alps, Apenines, Carpathians, Pyrenees...).  The subspecies Pinus mugo ssp. mugo is usually a multi-stemmed small tree or shrub up to 15' tall.  It appears very much like our native lodgepole pine in color, needle fascicles, and cones. There are selections from individuals, propagated by grafting, that can maintain a smaller and more dense habit.  Many are grown from seed and habit and eventual height is variable.

Windswept and frost pruned "krumholze" lodgepole pines can be found on high Sierra ridges. They are artistic, dense and beautiful. To achieve the same look on your landscape Mugo Pines you need to prune. All the new growth (candles) are sheared back or broken-off, about halfway, for a dense and sturdy growth habit.  Once they have been allowed to go "feral", un-sheard for several years, it is very difficult to prune back into a dense shrub.


The candles in the picture above are ready to be broken off.  It took me about 2 minutes to do all of them by hand, leaving some longer than others to accentuate irregularity or all evenly to achieve perfection.  It is extremely easy, don't be affraid.  If you miss a year or two here or there don't worry too much. It can be left unpruned and it may grow into a nice shrub but the open "woolies" are more susceptible to snow breakage and their ultimate size is often unpredictable.

The reason we prune the candles is because it is easy, the lateral buds have not completely formed yet and the wounds seal flawlessly.  You can use the same technique to prune branches and tips on other pines and on spruce.

This is a stunted white pine near Bishop, CA