Not all plants found in our northland gardens are equal. Some have significantly more value than others. One cannot rank them according to value. So many have certain features that despite their lack of beauty, or ugly habits, are simply needed in the landscape garden for perform a special function.
Shade elms used as street trees became beautifully formed tunnels for city traffic lining the boulevard spaces in our Minnesota communities. However, the trees have little value in the urban home garden of one story homes. Yet, for years these monsters were both planted and seeded themselves as weeds to populate the city’s landscape…..whether wanted or not.
Worse are the Silver Maples, (Acer saccharinum) which match the American Elms in size and possess exceedingly soft wood easily damage in severe storms, summer or winter. Planted in ones back yard not too far from your bedroom should have caused sleeplessness in Minneapolis and St. Paul when the wind and rain or sleet picked up about the time you went to bed.
Of all of the garden trees, and shrubs, for that matter, usable in the northern landscape garden, the one genus we could not do without is Thuja…..the arborvitaes….or as the old timers called them, “White Cedars”.
But even among these Thuya, not all varieties and cultivars are equal. And landscape gardeners can differ on which are more needed or more beautiful than others depending on their features.
One local landscape wholesaler has nearly twenty varieties or cultivars listed in their catalog. Over a ten year period they could have listed thirty different looks of arborvitaes at one time or another, for what is offered for sale differs from year to year.
And there are probablythirty to forty more various arborvitaes that are eminently usable for Minnesota landscape gardens. Some are more eminent than others.
Some are trees. Usually these trees are listed separately from lists of trees and instead are grouped into the category titled, “Uprights”.
Uprights suggest the tree is a vertical woody perennial growing more than a dozen feet in height. Upright also suggests that the tree is not a shade tree….that it doesn’t have a large enough canopy to cause shade. Yet, for those of you who know trees and are avid northern woods folks, you know that the White Cedar does develop a canopy, not by its own preference, but because the species is deer food of the first order. They will eat as much foliage as can be reached until the arborvitae grows beyond the stretches of these usually hungry Bambis.
Arborvitaes are at the top as a landscape garden tree because they do not have shade causing canopies. So one can grow any sun-loving perennial or flowering shrub within a grove of arborvitae.
Among the more narrow, tall and most elegant of these Thuja for Minnesota is the deGroot’s cultivar. Its stately form seems to create order to almost any grouping of perennials and shrubs.
It is certainly among my favorites and we use it often in our landscaping designs.
Among the many shrub cultivars I think I have two favoritesl…..Rheingold and Hetz Midget arborvitaes. Both can grow best in full sun for at least half a day. Rheingold is the only evergreen conifer that actually appears to have golden to orangish tips to its young foliage when grown in full sun.
Arborvitaes do not do well in dry areas, but much prefer the regularity of irrigation watering on a regular time scheme.
Among the Uprights, but fatter and more prominent forms, I do prefer the Sunkist or Yellow Ribbon Arborvitae. They are much the same plant. The tag attached to my Sunkist arborvitae, a major conifer in my front garden, announced that the expected height was up to 8 feet.
My Sunkist is double that size and appears to have no intention of slowing down its growth. Much of its foliar wealth comes from the dependable watering it receives from the irrigation system.
Woodward is a very, very large natural globe….I have seen them at twenty five by twenty five feet in size.
Arborvitaes often look as if they are struggling when they are forced to grow in deep shade.
Rabbits and mice love to devour arborvitae foliage in the winter time. This past winter, my Siberian arborvitae about 18 years old and twelve feet tall, was packed to the ground by last year’s Christmas rain and heavy snowfall. It had disappeared from sight all winter looking like a small snow drift. When it finally became release from its icy prison by March, half of the foliage on the ground side had disappeared. Rabbit droppings proved what the major culprit was…..but then mice almost always eat arborvitae in the winter whereever Thuja grow.
The Golden Globe is another natural globe which shows striking yellow folliage. It does turn color to a rather darkish green in winter, but regains its color usually by the first of March .
Arborvitaes are all pleasant to the touch and exudes a very strong fragrance when the foliage is pruned. They do better growing in good garden loam with a nearly neutral soil pH.
They are among the best uprights to be used for vertical sculpture and framing garden scenery.