The key to success with trees and shrubs in your yardscape will take place before you put a shovel in the ground. Plan, ask questions, and choose your trees and shrubs wisely. The ‘wisely’ factor is best translated into asking questions of yourself: Where is this tree going in my yard; What do I want from it in terms of shade, privacy, flowering, bird habitat, etc., etc. Mistakes at the beginning of the tree selection process can last a long time, cost money, and chew up time. These are just a few of the takeaways from the Durango Botanical Society’s recent workshop “Tips for Trees,” attended by over forty people on March 16 at the LaPlata County Fairgrounds. (Click Read More for full report)
Don’t just spray-and-pray
Not all insects and tree diseases are created equal, advised Darrin Parmenter, Horticulturalist and Extension Director for LaPlata County. The seriousness and solutions to insects and diseases will range from largely annoying (leaf spots, aphids, and spider mites) to highly threatening (oystershell scale, cytospora and bark beetles). The level of response depends on where your insect or disease issue fits on this spectrum. One rule of thumb is that harsh chemical solutions are seldom warranted, “don’t just spray-and-pray,” advises Parmenter. For aphids, for example, the mitigation may extend from doing nothing, as in letting natural controls ultimately take care of things, to spraying with a strong jet of water or a soap and water mixture. Cytospora Canker, Colorado’s #1 canker-causer for cottonwood, aspen, willow, spruce, and fruit trees, usually attacks weak or stressed trees and may require substantial pruning and mitigation.
Parmenter advises homeowners first recognize the insect or disease issue they are dealing with, before taking action. In others words, follow the physician’s creed: First do no harm. One of the most misdiagnosed issues is Fireblight, which actually only applies to trees in the Rosaceae or rose family such as apple, pear, and crabapple. A key telltale sign of fireblight is the so-called ‘Shepherd’s crooking’ of leaves (where the tips of the leaf curl inward). While devastating to commercial fruit producers and often treated with a variety of chemicals, homeowners might consider spraying with a 10% bleach solution or by mostly pruning 8-12 inches below the visible infection. Prevention of spreading through timely pruning is the best strategy.
Parmenter warns that one insect issue that could arise this year, owing to an especially wet winter, is the appearance of the tent caterpillar, which is prone to boom or bust population cycles. This pest can be voracious and is probably best identified by their conspicuous silk tents in the branches of host trees.
Bourey Advises Patience and Planning
When locating any tree or shrub, advises Lisa Bourey, landscape designer, horticultural consultant and owner of Passion Flower Farm, consider size, structure, leaves and buds, and the tree’s root system. In practice this means beginning with an evaluation of the mature size of the tree. Unless you’re into high-maintenance, do not plan on pruning to limit a plant’s growth potential. Or, if you’re partial to aspens remember the rhizomatic nature of these trees which can grow into large clonal colonies from a single seedling. Maybe better to enjoy aspens on a mountain hike unless you have a very large yard? Consider, too, the amount of water a tree will require and match that to your situation.
Think of a tree purchase on two levels, says Bourey: Above ground and below ground. How much sun will the tree get/require, does the prospect tree reflect an open branching structure, has it been pruned correctly, is the root system exposed? Below ground factors will include soil type, drainage, and rock content.
Maybe the best advice, Bourey counsels, is to be patient; it may well take a tree or plant 3-5 years to become established but after that settling in period, most plants are hardier than we give them credit for. Another thought on patience is: “Be willing to start small.” Small plants, she says, establish themselves faster and will grow at a more rapid rate than transplanted, larger, more mature plants. And, smaller trees and shrubs are easier to prune. Of course, if a privacy barrier is an important factor, then bigger will be faster and better.
The Tree Whisperer
Few people know Colorado trees as well as David Temple, arborist and owner of Trees of Trail Canyon. Temple is one of the nation’s few board-certified master arborists. The key to a long-lived, healthy tree is training the tree when it’s young and that includes strategic pruning. Pruning is necessary but pruning is both a science and an art, Temple says. “Trees do not heal, their cells only generate, building new cell structures on top of old. Pruning is also ‘wounding’ a tree but with proper pruning, cutting at the right spot, will generate new energy to correct structural problems and produce a healthier, longer-lived tree.
One of the hardest things for home gardeners and landscapers to accept is the efficacy of what Temple calls Rejuvenation Pruning, in effect cutting a flagging shrub or bush down to perhaps 3-6 inches from the ground. While that technique is scary for some homeowners, the rewards in terms of regeneration can be amazing. Temple related a story of pruning a huge lilac with six-inch diameter trunks but fading blooms to just a few inches from the ground; in just two seasons it had burst back to new life with huge, fragrant blooms.
After his remarks on pruning, Temple took the assembly into the Fairgrounds parking lot to demonstrate where and how certain trees should be pruned and the anticipated results. We can’t share all of Temple’s pruning tips here so check out Trees of Trail Canyon on YouTubefor some of his tips on growing, caring for trees. Search for Trees of Trail Canyon or David Temple.
For more information, contact: Darrin Parmenter at Darrin.Parmenter@colostate.edu, Lisa Bourey at firstname.lastname@example.org, and David Temple, email@example.com.
David Temple of Trees of Trail Canyon demonstrates proper pruning techniques to attendees of Durango Botanical Society's "Tips for Trees" seminar.