Trees, Shrubs and Vines

Index to articles

Diseases & Physiological Problems
  • Alcoholic Flux of Honey locust or white flux occurs where microorganisms ferment sap in cracks and other wounds in the bark and cambial region.
  • Bacterial Wetwood is a common disease affecting the central core of many shade and forest trees. A short discussion and photographs are provided along with a link for further information.
  • Blackheart Injury is a debilitating factor effected by both rootstock and apple cultivars. Blackheart, a form of winter injury resulting in the killing and plugging of xylem tissue, is so named due to the resulting oxidative brown or black discoloration of the xylem. Blackheart may not cause the outright death of the tree but has been implicated in tree decline and reduced productivity. It has been reported that damage may not be apparent when less than 20% of the xylem is injured, while trees sustaining greater than 50/% injury may not recover
  • Black Knot Disease Apiosporina morbosum is a very conspicuous and common disease of most species of Prunus, including sweet cherry and pin cherry. A photograph of the canker is provided as well as a discussion of the problem and its control.
  • Black Stain Root Disease of Conifers. The black stain fungus infects and kills several species of western conifers. The fungus colonizes water conducting tissues of the hosts roots, root collars, and lower stems, ultimately blocking the movement of water to foliage.
  • Chestnut Trees - a short history of their demise
  • Chlorosis - A summary of recommended steps to correction. Accurate and rapid identification of the problem is paramount. A listing of chlorosis-inducing factors is provided. These should be ruled out before drawing the conclusion the chlorosis is induced by an Fe deficiency.
  • Cytospora Canker Cytospora chrysosperma is a problem of many trees including aspen, cottonwood, poplars, apple, willow, honey locust and maple. A short discussion and photographs of this problem are provided. A link to additional information is given.
  • Cytospora Canker of stone fruit - Peach Cytospora Canker Leucostoma persoonii is a problem of members of the genus Prunus. This includes peach, apricot, cherry, plum (prune), nectarine and almond. This fungus can cause tree death in just a few years after infection..
  • The swollen trunk of this Tree of Heaven (Alianthus altissima) gives the impression it is related to the African Baobab tree. The problem may be due to a root encircling the base of the tree.
  • Fasciations - fascinating distortions of the plant world. The term refers to a flattened or ribbon-like appearance of the stem. Woody plants, annuals and even cacti are affected.
  • Frost Cracks are longitudinal cracks that occur in the bark and wood often extending several feet up and down and penetrating several inches into the trunks of affected trees.
  • Frothy Flux of Globe Willow
  • Included (embedded) bark is embedded between opposing branches, a branch and a main stem or two co-dominant stems creating a structurally weak point in the tree.
  • Natural Needle Loss by Evergreens in the fall is normal for many conifers. Even though these trees are called “evergreens” they do not retain every needle indefinitely. 
  • Juniper mistletoe - Phoradendron juniperinum is a species of leafless mistletoe that infects Juniperus scopulorum, Juniperus osteosperma, and Juniperus monosperma. Photos taken on the Colorado National Monument in western Colorado are included.
  • Mistletoes in Colorado Conifers
  • Powdery Mildew - This provides a photograph of powdery mildew on lilac, lists some susceptible plants and provides some control options. Additional on-like links and other references are provided.
  • Quince Rust alternates between Rosaceous hosts and Juniper (Juniperus/Sabina). The Rosaceous hosts of hawthorn rust include Serviceberry [aka Juneberry, Saskatoon & Amelanchier (genus Amelanchier)], apple (Malus), Pear (Pyrus) and Mountain Ash ( Sorbus)
  • Leaf Scorch of trees and shrubs.
  • Spruce Broom Rust - Chrysomyxa arctostaphyli is commonly associated with spiketops, dead branches, bole deformation, loss of increment, and mortality.
  • Sunscald - A mid-winter problem of trunks and branches.
  • Treating gravel roads with magnesium chloride for summer dust control and its affect on spruce trees (Picea engelmanni).
  • Why doesn't my tree drop its leaves in the fall? The reason is the tree did not respond to environmental cues.
Fertilizer Needs General Tree and Shrub Maintenance
  • Selecting a Landscape Maintenance Contractor Information to help you make the right decision.
  • Green Industry List Serve - Bulletin Board This ListServ is an electronic bulletin board, designed as a forum for the commercial 'Green Industry'. This provides the means of disseminating information regarding workshops, disease and insect alerts, announcements, and research relative to the industry. To be added to the list, contact Dr. Curtis Swift.
  • Mulches, a comparison of; temperature relationships and plant growth. Rubber mulch was compared with three bark/wood mulches and bare non-mulched soil to determine the surface temperatures of each, the soil temperature below each mulch, as well as the leaf temperature and overall growth of plants in the mulched areas.
Growth and Development Insect Pests
  • The The Ash Borer - Podosesia syringae Harris is a serious pest of the European ash (Fraxinus excelsior) planted throughout Western Colorado.
  • Black Vine Weevil - Otiorhynchus sulcatus (Fabricus) is seldom seen as the adult feeds at night but can cause considerable damage to flowers, shrubs and greenhouse plants.
  • Eriophyid Mites are tiny creatures that affect many different plants.
  • The Pine Eriophyid Mite Trisetacus ehmann feeds under the sheath of the fascicle at the base of the needles and can kill buds and cause yellowing, distortion and death of needles.    Since these mites live in the leaf sheath at the base of the needle, they are hard to control. 
  • European Elm Scale - Gossyparia (=Eriococcus) spuria (Modeer) caused the die back of twigs and branches of elm trees.
  • The Grape Leafhopper is a pest of grapes as well as numerous ornamental shrubs and flowers.
  • The Ips Beetle - Ips species - Engraver Beetle is a serious pest of pine and spruce. There are twenty-five species currently recognized in the Western United States. In Western Colorado Pinon pine (Pinus edulis) is the favored host of one of these Ips species (Ips confusus).
  • Pinyon Pine Mortality due to Ips
  • Pinon Ips Prevention and Control
  • Protection of Pinons in Construction Sites
  • Thinning the Pinon-Juniper Forest to Improve Pest Resistance
  • Japanese Beetle - Popillia japonica was been found in Palisade (Mesa County) in mid-summer 2002. The initial discovery was based on a single adult Japanese beetle brought to Bookcliff Gardens, and forwarded to the Mesa County Extension office on July 23. A discussion of the insect and its life cycle is provided. The trapping protocol for this insect is also included.
  • Peach Tree Borer THe ife History and Management Options for Western Colorado Peachtree borer (crown borer), Synanthedon exitosia, is a pest of peach, cherry, plum, prune, almond, and apricot.
  • Pinon "Pitch Mass" Borer - Dioryctria ponderosae is reported as a serious pest of pine in the Great plains from South Dakota to Kansas and Colorado (Harrell, 1993). In Western Colorado native populations of Ponderosa (Pinus ponderosae) and pinon pine (Pinus edulis) are attacked.
  • Pinon Twig Beetle Pityophthorus sp. and Pityogenes sp.) have damaged many trees in western Colorado. Pinyon and Mugo are especially vulnerable. Other pines, true firs, Douglas-fir, and spruce are also attacked.
  • Red Mulberry Bark Borer - Parelaphidion incertum (Newman) - A pest of the Box-elder in Western Colorado. The larvae of this beetle bores into the trunk and large branches of boxelder (Acer negundo).
  • Spruce Tree Borers - This fact sheet identifies insects that bore into spruce trees by identifying the galleries they create.
  • Western Grapeleaf Skeletonizer - Harrisina brillians
  • Western Grapeleaf Skeletonizer appeared in the vicinity of Montrose (Montrose County) during the summer of 2002.
Irrigation Landscape Specifications Licensed Tree Care Providers This list is provided by the City of Grand Junction. Be sure to hire a company that has been vetted for its professionalism and abilities.
Planting Mycorrhiza and its use in the landscape. Mycorrhiza is a hot item in the 'Green Industry', but does it work or is it another snake-oil product? Pruning, Bracing and Cabling
  • Cabling and Bracing trees Trees that have split can sometime be saved by cabling and bracing. This needs to be accomplished correctly. Note the location of the support on page 8 of this publication.
  • The Callusing of Wounds in Trees Trees, shrubs and other woody plants bury their wounds under new tissue. The way the pruning cut is made determines how the pruning wound forms wound wood and how the wound closes.
  • Disinfecting Pruning Tools
  • Pruning saws, shears and other pruning tools can spread disease organisms if not properly disinfected.
  • Don't Destroy your large trees by Topping. Topping is the indiscriminate removal of a tree's crown, cutting off large branches and the main stem of the tree, leaving large branch stubs.
car crushed by tre An excellent series of photographs by Dutch Afman of a tree that fell on a car as a result of topping.
  • Improper Pruning Techniques Limbs one inch or more in diameter should be removed with three cuts to prevent splitting of the wood and tearing of the bark.
  • Pruning damage . These are excellent examples of how not to prune a tree. Many of these trees will develop internal rot and eventually need to be removed before injury to students or staff occurs.
  • Pruning in Holland - Pollarding. Pollarding is an extreme type of pruning where all the new growth is removed annually. Some parts of the world continue this pruning technique.
  • Selecting a Tree Trimmer Choosing the wrong tree trimmer could result in a poor pruning job and the development of internal rot resulting in a hazardous situation causing property damage, personal injury or death.
  • Protecting Trees During Construction will prevent healthy trees from construction damage.
  • Roses
  • Selecting, planting and caring for roses. Links to workshops, winter protection and other information are provided.
  • Winter Care of Roses
  • Seedling Trees and Shrubs
    The Seedling Tree Program of the Colorado State Forest Service is designed for conservation plantings such as windbreaks, shelter belts, living snow fences, wildlife plots, noise abatement, erosion control, fiber and fuel production and Christmas tree plantations.
Selected Trees and Shrubs Trees and Vandals
  • These pages consist of photographs and discussions on tree damage.
Winter related Items Western Colorado Symposia on Saltcedar (Tamarisk) and Russian Olive