Conifer Corner - Department of Horticulture - Michigan State University

By Wendy Klooster and Bert CreggDepartment of Horticulture, Michigan State UniversityIn this edition of Conifer Corner, we are continuing our tour of the conifer formclasses recognized by the American Conifer Society (ACS) with Broad Uprightconifers. The subtitle “Blue Collar Conifers” is a reference to the unsungstatus of these important landscape trees.July 200837

Strong, silent types. Picea abies ‘Parviformis’ (left) and P. pungens ‘Montgomery’(right) provide the backdrop to let other plants shine.If they could, Broad Upright conifers wouldwear Carhartts and carry a lunch bucket. Talkabout no respect, even the definition of the categoryis a definition by default. The American ConiferSociety (ACS) guidelines for form classificationsare similar to those for size, but these categoriesare based on the growth habit (proportion ofvertical to horizontal growth, and branch structure)rather than growth rate. According to the ACS,if a tree is upright but is not rounded, narrow orweeping it is considered broad upright (seesidebar). As with size classifications, ACS, coniferform distinctions can be a bit subjective and alsodepend upon local growing conditions and treeage. For example, many plants classified as BroadKorean pine (Pinuskoraiensis) is a classicexample of a ‘bluecollar’ conifer. Thishardy and reliableplant can set the stagefor other specimens.38 The Michigan Landscape

Upright, may start off narrow or pyramidal andthen become more rounded or spreading with age.While broad upright conifers may feel likesecond class citizens compared to elegantfastigiate forms or show-topping irregular forms,it is hard to overestimate their overall importancein landscape design. These are extremely commonforms of landscape conifers that serve as thebackbone of many landscape designs. The ACSlists over 400 cultivars of broad upright conifers;more than any other single form class. What peoplemay not realize, however, is that this categoryincludes trees of all sizes from miniature to largeand includes almost all genera of conifers. Broadupright conifers are extremely versatile and serveas the backbone of many landscapes. Intermediateor large varieties are often planted in a row or areeven offset a little to form an effective windbreak.Since these trees grow quickly, both upward andoutward, they can be planted at a fairly wide spacingand still provide privacy and protection within afew years. Intermediate trees are sometimesplanted in a row and kept pruned as a hedge, butthis requires regular maintenance. Rememberthat broad upright trees will get rather wide atthe base, so they should not be planted too closeto a structure or walkway.The natural form of broad uprights is usuallyso desirable that many landscapes include one asa specimen tree. This is the tree that first drawsthe viewer’s eye and maybe even draws the wholeviewer close in order to feel the foliage or bark.Kerry Gee of Gee Farms near Stockbridge,Michigan, advises landscapers to spend half oftheir budget on a single specimen tree, and thenuse the other half to fill in with more basic plants.If this sounds extreme, consider that large andunusual trees can cost over a thousand dollarsdue to the time and resources it takes to producethem. Sometimes all that it takes is one look toknow that a tree is worth the price.If the landscape already has a large specimentree, a grouping of smaller broad uprights can beused on the other side to give the landscapesymmetry. This contributes balance, one of thebasic elements in landscape design. In this case, afew small trees planted together have the samevisual strength as a single large tree. Texture isanother design element and is a good way toprovide variety and interest without disruptingbalance. Texture is achieved by selecting cultivarswith different needle shapes and sizes. The small,compact foliage of many Chamaecyparis, forexample, provide a nice contrast to the stiff, sharpedges of spruce needles. Trees also come in avariety of colors from greens and blues to whitesand yellows. Many green cultivars have yellowcounterparts, such as Chamaecyparis nootkatensis‘Variegata’, which can be very striking. However,it is important to avoid the temptation to plantone of each as they can be overwhelming andmake the landscape look like a circus. When usedsparingly, blue or yellow conifers can add just theright amount of visual interest and appeal.Pinus koraiensis ‘Silver Ray’,Silver Ray Korean PineJuly 200839