Plants Attacked: Juniper, arborvitae, other cedars, pine, hemlock, spruce, Chinese elm, honeylocust, primarily. Also on crabapple, maple, sycamore, box elder, willow, linden, poplar, and many others.

Scale insects are a peculiar group and look quite different from the typical insects we encounter day to day. Small, immobile, with no visible legs or antennae, they resemble individual fish scales pressed tightly against the plant on which they are feeding. There are over l50 different kinds of scales in Virginia. Many are common and serious pests of trees, shrubs, and indoor plants.

Native to North America, the fall webworm occurs throughout the United States and southern Canada. Its hosts include more than 100 species of deciduous forest, shade, and fruit trees, with preferences varying from region to region.

Fusarium wilt is a common and lethal disease of mimosa (Albizia julibrissin)1, also commonly known as silktree. In the United States this disease occurs in the east from New York southward and also in Louisiana, Arkansas and California. Fusarium wilt is caused by the fungus Fusarium oxysporum forma specialis perniciosum. Albizia spp. are the only known host of F. oxysporum'' f.sp. ''perniciosum''. Fusarium oxysporum f. sp. perniciosum colonizes and clogs the tree’s vascular (water-conducting) tissue, and interferes with the movement of plant sap. This results in relatively rapid tree death.

Pales weevil feeds on all pines within its range. It will also feed, although to a lesser extent, on Douglas-fir, fir, hemlock, juniper, larch, northern white-cedar, and spruce.

Twisted and curled needles are the most apparent damage from feeding by the balsam twig aphid. Feeding can also cause roughened bark on the twigs. Extensive feeding can cause a general decline and reduced vigor of the tree, yet in many cases is cosmetic and not particularly damaging. The major problem is that curled needles reduce the marketability and value of Christmas trees. Balsam twig aphids also produce honeydew, a sticky material that drops to needles and twigs below. At times the honeydew can become a growth medium for sooty mold, which turns the needles and twigs black.

Foliage drops, needles usually shorter and may kill tree over period of years - most damaging on seedlings and young saplings. Often black sooty mold is associated with infestations.

Invasive exotic species are plants that are not native to a given area and have the ability to out-compete indigenous plant species. Invasive exotics are often brought into their non-native surroundings by humans with good intentions.

Autumn olive was introduced to the U.S. from Japan and China in 1830. It was originally planted for wildlife habitat, shelterbelts, and mine reclamation, but has escaped cultivation. It is dispersed most frequently by birds and other wildlife, which eat the berries.

Ailanthus, also known as tree-of-heaven and paradise- tree, is a major nuisance to foresters, farmers, and homeowners alike. Its prolific seeding and ability to sprout from roots and stumps and grow quite rapidly just about anywhere make it a serious competitor and threat to native species and cultivated crops. On top of that, ailanthus is allelopathic, producing substances that are toxic to and inhibit the growth of neighboring plants.

Several species of Asian honeysuckle have been introduced in the United States for their ornamental and wildlife values. Honeysuckle is perhaps the most widespread exotic invasive in the U.S., now found in at least 38 states. The Asian honeysuckle produces abundant seeds which are dispersed by birds and other wildlife. It also spreads by sprouting from its roots. Because it tolerates shade from other plants, it grows in forest understories.

Forest management is a complex process. Silviculture—a system in which healthy communities of trees and other vegetation are established and maintained for the benefit of people—uses forest ecology to guide complex management prescriptions that mimic forest disturbances and processes. Silvics—the natural characteristics of trees—play an important role in prescribing effective silviculture.

It is often necessary to provide extra attention to plants in the fall to help them over-winter and start spring in peak condition. Understanding certain principles and cultural practices will significantly reduce winter damage that can be divided into three categories: desiccation, freezing, and breakage.

The spectacular spring flowers of azaleas and rhododendrons make them among the most popular garden shrubs. However, azaleas and rhododendrons are shrubs for all seasons. Throughout the summer and fall the leaves add a pleasing, deep‑green color to the garden. Some deciduous azaleas add bright fall color before the leaves drop. In winter, some varieties stand out with large, evergreen leaves.

There are many tree species that can be successfully grown in Virginia, but are rarely seen in our landscapes. Although not ordinarily recommended or readily available, these trees may be useful to carry out a specific landscape theme, to substitute for an exotic type which is not locally adapted, or may be prized for unusual form, flowers, fruits, bark, or foliage.

Conifers, also known as narrow-leaved or needled evergreens, are planted primarily for the attractiveness of their evergreen foliage. The variety of sizes, shapes, and colors available contributes to their popularity. Conifers range in size from prostrate plants growing only a few inches tall to large trees. Shapes include flat ground covers; horizontal spreaders; upright, pyramidal forms; and even weeping and contorted forms. Foliage color ranges from a gold and cream variegation to all shades of green, gray-green, and blue-green.

There are a large number of highly ornamental broadleaved evergreens. However, many of them require special attention if they are to develop into attractive, long-lived plants. Wide fluctuations in temperature, prolonged dry periods, drying winds, and bright sunshine are not ideal conditions for most broad-leaved evergreens, yet these conditions frequently occur in Virginia. Good soil preparation and a carefully selected location will help ensure the success of these plants. However, the year-round beauty and special effect that they give to the landscape make them well worth the extra care needed to grow them.

Trees are the basic element for any landscape plan. They set the stage for the entire home grounds design. The type used and their location determine to a great extent what other plantings are appropriate. Providing shade usually requires tall, sturdy, long-living species. Density of foliage, which determines the amount of shading, is important. A tree such as a Norway maple will produce a very dense shade that prevents other plants from growing under it, while a honey locust will produce a light partial shade which is not a hindrance to other plants growing below it. Deciduous trees should be used to shade the south windows of a home in the summer, thus allowing the sun to penetrate in the winter.

Maintenance programs should be developed for trees and shrubs in both residential and commercial landscapes. A good maintenance program includes monitoring and controlling insect and disease problems, suppressing weed competition, and making timely applications of water, mulch, and fertilizer. Tree and shrub fertilization is especially important in urban and suburban areas of Virginia where soils have been altered due to construction. These urban soils tend to be heavily compacted, poorly aerated, poorly drained, and low in organic matter. Even where soils have not been affected, fertilization may be needed as part of a maintenance program to increase plant vigor or to improve root or top growth.

Los árboles y arbustos necesitan nutrientes para crecer y estar sanos. Los tres nutrientes más importantes son nitrógeno, fósforo y potasio. Un análisis de suelos es siempre la mejor manera de saber qué nutrientes se necesitan y la cantidad necesaria de cada uno.

The term “mulch” refers to materials spread or left on the soil surface as protective layers, whether organic or inorganic, loose particles or sheets.

Planting trees in aboveground containers and planters is becoming a common practice on sites that are not suited for inground planting. Containers differ from raised planters in that they are usually smaller in volume and moveable, whereas planters are generally larger, and often built as part of the permanent hardscape (paving, etc.). The greatest challenge in selecting trees for containers and planters is in choosing trees that can survive temperature extremes, and that can establish roots in a limited volume of substrate (potting soil). Consider several factors when selecting containers and trees including environmental influences, container and planter design, substrate type, and tree characteristics.

Hot landscape sites require special consideration before trees are planted. Trees can survive, and even thrive, in hot sites if the site is prepared correctly, if heat-tolerant species are selected, and if the trees are properly maintained. A variety of different locations and situations qualify as hot landscape sites.

Using trees as living screens can easily enhance living and working spaces. Before selecting trees for screening, first determine the screen’s purpose, whether functional or environmental. Screening can be used to define an area, modify or hide a view, create privacy, block wind, dust, salt and snow, control noise, filter light, and direct traffic flow.

To grow, all trees require air, light, water and nutrients. Some trees can survive over a wide range of climatic and soil conditions, whereas others are very site specific. Both wet and dry sites present establishment and growth challenges, making selection of the right tree for the right site very important.

The trees and shrubs on your new home site are growing poorly, so you take samples to the Extension office and the agent suggests a soil test. Test results show that your soil has a pH of 4.5, which is rated as strongly acid. The agent suggests you either take corrective action to raise the pH or grow different plants. What do the test results mean? What are “acid soils” and what does pH measure? Why does this matter to your plants? How can you correct the situation or what alternative trees and shrubs can you grow?

Concentrated sodium (Na), a component of salt, can damage plant tissue whether it contacts above or below ground parts. High salinity can reduce plant growth and may even cause plant death. Care should be taken to avoid excessive salt accumulation from any source on tree and shrub roots, leaves or stems. Sites with saline (salty) soils, and those that are exposed to coastal salt spray or paving de-icing materials, present challenges to landscapers and homeowners.

Few residential trees die of “old age.” Mechanical damage and improper tree care kill more trees than any insects or diseases. Avoid making the tree-damaging mistakes shown in the diagram below. Few of these items alone would kill a tree, but multiple problems will certainly stress, and could eventually kill, a tree.

Select trees and shrubs well-adapted to conditions of individual planting sites. Poorly-sited plants are doomed from the start, no matter how carefully they’re planted.

The most effective form of plant disease control in the landscape is prevention. Disease prevention can be as simple as choosing the right plant for the right place at planting time. This fact sheet was developed as a guide to shrubs that generally experience few problems in Virginia landscapes. Using these species for new plantings should help you avoid troublesome disease and insect problems in your landscape.

Many of the tree species commonly planted in Virginia landscapes suffer from disease problems. Although some diseases can be cured, most must be controlled on a preventative basis. The best option for new plantings is to choose species that have a low risk of developing disease. Listed below, in alphabetical order, are some choices of problem-free trees for Virginia landscapes.

Botrytis blight is a common fungal disease that confronts the peony grower each spring. The fungus Botrytis cinerea blights stems, buds, and leaves and can cause plants to look unsightly, especially in wet springs. This fungus causes disease on a wide variety of herbaceous and woody ornamentals, as well as vegetables and small fruits. It is sometimes referred to as “gray mold” because of the conspicuous, fluffy, gray fungal growth that forms on infected plant parts.

Powdery mildew fungi attack a variety of ornamental plants grown in Virginia.

Leaf and flower gall is a disease that is common on azaleas and camellias in the spring. The disease has also been reported on other members of the plant family Ericaceae. It occurs in home landscapes and nurseries, and is often seen on flame azaleas in the forest in the spring. The disease is caused by species of the fungus Exobasidium.

Photinia, a shrub belonging to the plant family Rosaceae, is a popular landscape shrub in the southeastern U.S. Several species are grown, but the most popular is the hybrid Photinia ×fraseri, or “redtip”, so named for its bright red, immature foliage. The biggest drawback to growing photinia is a leaf spot disease caused by the fungus Diplocarpon mespili (syn. Entomosporium mespili) to which redtip is highly susceptible.

English boxwood, are susceptible to several diseases that can decrease their effectiveness in established plantings. The major diseases of boxwood are discussed

Rose rosette disease (RRD), a disease believed to be caused by the recently identified Rose rosette virus, has been spreading through much of the wild rose population of the Midwestern, Southern, and Eastern United States for years.

Landscape trees are valuable assets to your property and for your community. Keeping your trees attractive, healthy, and safe requires careful attention to their planting and care throughout their lives. While many people have a green thumb, there are situations that arise where the expertise of an arborist is needed to address complex or potentially hazardous tree care needs. The purpose of this publication is to inform home owners, property managers, municipal planners, and others about the tree care services provided by an arborist and the steps that should be taken to hire a qualified arborist.

Many forest owners value their forest for wildlife habitat, recreation, and aesthetics. Given accurate information, many want to manage their woodlot using sound silviculture but clear-cutting as a regeneration method may not be visually acceptable. While a profitable timber harvest is of interest, a visually pleasing residual stand may be more important. To meet this objective, Stand D1 of the SVAREC forests was selected to demonstrate All-Age Management using group selection silviculture and individual thinning of select trees to create four age classes.

Most forest owners value their forest for wildlife habitat, recreation and aesthetics. Given accurate information, they may manage their woodlot to achieve these and other goals using sound silviculture. Thinning over-stocked woodlots is one silvicultural management tool. Thinning can modify spacing and diversity of species to meet desired goals which may include timber, wildlife, aesthetics and more. Thinning also improves woodlot vigor by removing over-mature, suppressed, defective or weakened trees. To meet theses objective, Stand D2 was selected for a thinning research & demonstration site.

Research into the attitudes and actions of private forest landowners shows that although very few own their forestland for the purpose of producing timber, most will sell timber at least once in their lifetimes. Private forest landowners sell timber for a variety of reasons that range from purely financial to solely for management purposes. Often landowners do not consider selling timber until they have an immediate need for cash. Other times the landowner has planned an immediate commercial thinning with a full timber harvest scheduled in 10 years. Whatever the reason(s) for a timber sale, careful consideration of objectives is paramount.

Timber harvesting is a valuable tool to help forest landowners realize certain financial and land management goals. Following are some suggestions to consider before selling timber.

Restoration of shortleaf pine (Pinus echinata Mill.) in Virginia has become a priority of various state and federal agencies. For shortleaf pine restoration to be successful in Virginia, private lands must be considered because 89 percent of forestland in Virginia is privately owned, and most private landowners are likely to use commercially available seedling sources. Shortleaf seedlings from commercially available sources in Virginia, Arkansas, and Missouri were planted in two sites in Southeast Virginia to test growth and yield. After one year, height and ground-line diameter were measured and observations were made on health and mortality of the plants. The Virginia seed source was significantly taller than the Arkansas source. At the first site, mortality and disease were low, but at the second site, mortality and poor health were very high, possibly due to soils combined with weather conditions. No significant seed source effects on disease and mortality were found at either site.

Galls are abnormal growths of plant tissue induced by insects and other organisms. Gall-making parasites release growth-regulating chemicals as they feed, causing adjacent plant tissues to form a gall. The parasite then develops within the relative security of the gall. Galls come in an endless variety of forms. Many are strikingly colored or curiously shaped. Each gall-making species causes a gall structurally different from all others. By noting the type of host plant and the structure of the gall, one can identify the gall-making mite without actually seeing it.

Rice-shaped holes about 1/16 inches result from adult feeding. Larval feeding forms mines, usually two per leaf. If they are both on the same side of midrib, one is extensive, and the other dwarfed. If the insect lays eggs on opposite sides of the midrib, both mines develop normally.

Description of Damage: The bark becomes roughened and encrusted with scales. Branches and limbs die back and result in a rapid decline in tree vigor, occasionally resulting in the death of trees. Seriously weakened trees are common in Virginia as a result of scale populations, especially red and silver maples.

To provide leadership in safeguarding and protecting the ornamental horticulture industry, historical gardens and landscape plantings from boxwood blight.

Since 2015, Extension specialists from Virginia Tech (VT) have visited and collected plant and soil samples from several large areas of dying great rhododendron (Rhododendron maximum) in Virginia’s mountainous regions. In 2016 VT specialists met with Virginia Department of Forestry, US Forest Service personnel, and other experts to revisit some of these sites. No consistent cause of this mortality has yet been identified. It is possible that a variety of factors are stressing the rhododendrons in these areas to a point where opportunistic pathogens or insects can successfully attack and kill them. The following information summarizes our observations and diagnostic results from four separate great rhododendron mortality sites in Virginia. This information is not equivalent to a research study, which would also include samples taken from healthy great rhododendron for comparison; however, we are confident that we have ruled out two diseases that are frequently mentioned both online and anecdotally as a cause of this mortality, specifically Phytophthora root rot and Botryosphaeria dieback.