I am frequently reminded by my friends, living in much more harsh climates than we enjoy in the Pacific Northwest, that they have a much more limited pallet of dwarf conifers to choose from for their gardens. Those folks must endure hotter and more humid summers and far more colder winters with sub-freezing temperatures, that I can only imagine. Here in my corner of the world, I am able to grow almost any but the most tropical conifers. When a friend from Plentywood, MT asked me for advice for their new landscape, I must admit it was a real challenge to find an assortment of plants that would create a pleasing garden, with year-round interest, in their very harsh climate.
One of the most hardy conifer “families” that I know of are the mugo pines. These tough plants are native to the high elevation mountains of Europe and have endured cold temperatures and freezing winds for thousands of years. There are many wonderful dwarf selections of these extremely hardy pines available to local gardeners through independent garden centers.
Many of the quality cultivars of mugo pine, which are commonly available, grow as low, mounding plants with dark green foliage. There are some whose color changes to shades of gold through the winter months, and they all have different growth rates from the tiniest miniatures to larger, more open growers. One in particular stands out from the crowd due to its upright, oval shape.
I remember hearing Jean Iseli and Don Howse talking about the day they were walking through a field of Pinus mugo seedlings. This field was probably 10-12 years old and there were thousands in a wild assortment of shapes and sizes of these young conifers. The two men were looking for special characteristics – extraordinary form, shape, growth rate, needle size, color — anything that they believed would make the plant worthy of reproducing and bringing into production at the nursery. As they were walking along, Jean came across one small tree and exclaimed, “That’s one big tuna!” They tagged the plant and continued on their way. That following winter the plant began to be propagated and was given the name, Pinus mugo ‘Big Tuna’. Personally, at the time, I was very skeptical about the name, but the plant is extraordinary! It is definitely one of my favorite mugos, and if I had a top-ten list of conifers, it might even be on that list.
Pinus mugo ‘Big Tuna’ is a dwarf, but it might be considered to be within the intermediate growth rate as designed by the American Conifer Society. When young, it shows great vigor and will advance with 6-8 inches of new growth per year. As the tree matures, that rate seems to moderate and the tree will form a large oval shape, somewhat taller than wide. The original mother of all ‘Big Tuna’s was planted in the Iseli Nursery main office landscape back in the mid-1980s and is a beautiful specimen today. I estimate that the tree is close to 15 feet tall and nearly 12 feet wide at its broadest point, about midway up the tree. Discovered in a group of seedlings planted in (or prior to) 1976, this excellent specimen is nearly forty years old!
‘Big Tuna’ is a great specimen, not only for those folks living in our colder climates, but also for those of us gardening in more temperate areas of the world. I can image a row of ‘Big Tuna’s making a formidable hedge in time. Its uniform shape and compact habit would make it useful in a formal landscape in place of plants that may require annual shearing to maintain their tidy form.
Versatile, compact, unique shape, reliable and extremely cold hardy. I suggest that you go out and catch a ‘Big Tuna’ for your garden!