Mugo pine with cones
(Continued from Mugo Pines 2)

Most people plant Mugos with a final height in mind. Often there is a plan; they are planted with a group of companions, a desired look expected. This will require the maintenance of some of the plants to keep their form. Pruning, the scientific, careful removal of plant branches to promote health and better asthetics, is what we need to do.

Pines have a few hard-wired rules for pruning. Easily learned, once you are comfortable with them, a lot of options of shape and form will be easy for you to achieve.

Natural growth and form

Pines form their buds in the previous growing season, the buds that will grow this years shoots were formed last year. When the bud opens and the shoot begins to grow, usually in the first half of June, it will complete its year’s growth quickly, normally in about three weeks. Conifers have one annual growth flush. This new shoot, called a candle, is initially very soft, green rather than a greyish colour, and the terminal bud that will grow at its outer tip is still forming. During this time, the candle can be cut to any length and the terminal bud will establish at the cut end.

Cutting anywhere between shoot tip and last year’s bud scar is an internodal cut. Nodes are important because this is where buds naturally occur, where it is easiest for the plant to grow from. I do not usually make internodal cuts, but green Mugo candles allow it. Cut internodally later in the season, and no bud will form and the cut shoot may die back to the branches below it. If doing 100% height control, be careful not to cut below last year’s bud scar.

The soft green candle with an incomplete bud is magic; you can cut anywhere and keep a natural, unpruned look. This means that a Mugo’s size can be fully controlled and kept where you want it with annual pruning. I annually prune a tight group planting of approximately 30 Mugos in Britannia that I call the sea of Mugos. Kept under control with near 100% growth control for over 20 years, no one sees the hours of pruning, just the beautiful, undulating, waist-high waves of Mugos.

If you like the form and natural look of your Mugo, thats good. Let it grow for several years until it reaches your desired height, and then begin your annual pruning. There is a misconception that you always have to trim the candles on Mugos. Not so. Prune only if you wish to have a denser form or to control height. Mugos that are fast growers with over a foot of annual growth, never pruned, are the runaways I spoke of, and make beautiful trees.

(Photo credit: “Pinus mugo cone 02" by Nova, licensed under CC BY-SA 3.0.)