Brown evergreen needles, needle tips and branch tips are a common sight during the winter and early spring months in Colorado. These are all examples of winter injury usually caused by the drying winds, lack of snow cover, fluctuating temperatures, and low soil moisture that are typical of Colorado’s fall and winter seasons. Evergreen needles…
Puncture vine is a noxious weed sometimes called “goat head.” It’s most commonly found in eastern Colorado at elevations below 6,500 feet, in disturbed soils and vacant lots. It’s a low-growing, mat-forming plant with small leaflets and one-half inch wide yellow flowers. Trailing stems may reach one to six feet long in the summer. Hard…
With all of the news about mountain pine beetles, it is easy to mistakenly believe that a natural fall phenomenon – needle drop on pine trees – means that pine beetles have attacked a tree. If pine needles turn brown from the interior of the tree, and the outer needles stay green, there is no…
The most common plant abnormalities show up as curled or cupped leaves. insects, mites, disease organisms, herbicides and weather events can lead to malformation of leaf, stem, flower and fruit tissue. Examination of the leaves is the first step in diagnosing the problem. Insects, such as aphids, can be seen unaided, but viruses and mites…
Many flowers enliven xeriscape landscapes. They can be mixed with shrub borders, planted as edgings, or used with mulches as alternatives to turf areas. Perennials and annuals that meet the low-water requirements of xeriscaping are available at most nurseries and Garden centers. Before planting flowers, improve the soil to foster root growth. Locate the Garden…
Leafy spurge is a noxious weed of foreign origin that infests over 100,000 acres in Colorado. Leafy spurge is a creeping perennial that reproduces by seed and vegetative buds on the roots. It has an extensive root system with vast nutrient reserves that allow recovery from stresses and control efforts. Leafy spurge displaces grasses and…
Desiccation in woody plants is common in Colorado, because soils range from sandy to clay and plants rely almost totally on supplemental watering. In addition, nearly all woody plants found in Colorado are imported from different parts of the country and have varying moisture requirements. Symptoms of desiccation appear when too little or too much…
Many Coloradoans live in areas where deer regularly visit. While it’s not hard to understand why deer consume the same vegetables that humans eat, additional “deer salads” include annual and perennial flowers as well as trees and shrubs. Deer-resistant plant lists have been put together but the problem is that deer in different areas appear…
Wet, cool springs and early summers promote prolific growth of two legume family weeds in lawns, white clover (white flowers) and black medic (yellow flowers). Leguminous weeds can be both common and competitive in lawns that have not been fertilized adequately with nitrogen for a couple of years. Regular fertilization, especially late season (September-early November)…
Purslane is an annual weed that germinates after soil warms in early summer. A native of Europe, purslane is related to the portulaca or moss rose grown in flower Gardens. It has succulent leaves and a low-growing, mat-like growth habit. Clumps may grow to two feet in diameter. Purslane is a problem weed in flower…
Russian thistle (Salsola tragus) and kochia (Kochia scoparia) are common annual broadleaf weeds that become “tumbleweeds” in the fall. These plants can be problematic in many situations where the soil is highly disturbed. These annuals can produce thousands of seeds per plant and the key to control it to keep them from going to seed.…
Iron chlorosis is a term describing leaf yellowing (lack of chlorophyll) due to insufficient iron. Iron is a mineral essential for plants to make chlorophyll, in turn needed for photosynthesis. Lack of iron in a tree may be due to a high iron need, less effective iron uptake, or insufficient usable iron in the soil.…
