Author: Burkholder PHC

Corrective pruning is a technique meant to maintain or enhance a tree’s health by removing dead, diseased, weak, or otherwise unhealthy or unsafe branches. Corrective pruning can be beneficial to both the tree or shrub as well as the landscape as a whole.

The main benefit of corrective pruning is that your tree will be healthier and more attractive. You can also reshape your tree’s canopy if you have accidentally allowed the structure to become too dense or if you want to create a more open look.

Removing dead or diseased wood allows light and nutrients to reach healthy parts of the tree. Diseased wood can be treated with an appropriate fungicide if necessary. Pruning can also help thin out a canopy which is sometimes necessary to allow more sunlight and air circulation. One reason is that too many branches close together means more competition among branches for sunlight, and as can often happen, some limbs will get more sunlight at the expense of others. Overly dense branches can make it difficult for certain stems to properly absorb enough rainwater or air to circulate within the canopy.

Trees can be afflicted by many issues that weaken the structural integrity of the tree, which increases the risk of branches (or the entire tree in severe cases) falling or breaking off to damage whatever is below or beside them. For example, many tree species are prone to developing codominant stems, where a tree has two trunks that are similar in diameter. Think of a tree whose trunk splits and forms a Y-shape. In this instance, both codominant stems compete, creating a weak upper structure and likely breaking apart in harsh weather conditions.

Pruning back branches that are growing too low down on a trunk helps prevent damage from snow and ice, which can break off large portions of bark in winter storms if they are close enough to ground level. Vulnerable branches at any height can break off without warning and damage property or persons beneath.

In the case of codominant stems, a certified arborist can prune one of the stems, reducing or removing segments or entire branches, so any new growth occurs around a single, strong trunk. Arborists can selectively prune branches to create a more stable, safe, and healthier tree.

Reducing long limbs that are difficult to reach and eliminating unsightly growth at the base of a tree will enhance the beauty of your landscape.

Corrective pruning is a far more complex process than simply cutting off tree branches. Therefore hiring a professional certified arborist is recommended.

• The tools need to be adequately cleaned to prevent further spreading or introduction of new diseases.
• Specific tools are required to prune trees correctly.
• Pruning requires carefully examining branches and making exact, precise cuts to maintain a tree’s health as much as possible.

For the best results for your trees and to ensure safety, having a licensed and insured tree specialist perform the work is the best decision.

If you believe that your trees need corrective pruning, send us an email or give us a call. Burkholder PHC has a team of experienced, qualified arborists who will visit your property, conduct a plant health care evaluation, diagnose the problems, and inform you of the recommended treatment options. In addition, we provide a proactive approach, helping encourage and maintain your trees’ health and appearance. Contact us today for a free consultation.

Growth regulators are a group of chemicals used to modify the various growth processes in plants. These chemicals help with many issues in a plant’s lifecycle, including suppressing vegetative growth and stimulating flowering, controlling plant height, enhancing plant branching, and enabling plants to flower during short-day conditions (during late fall and winter). The chemicals used can be found inside plants already but are sometimes modified to improve or lower their efficiency and modify specific processes.

Plant growth regulators are sometimes referred to as plant hormones because the chemicals act similarly to human hormones. Hormones are chemical messengers that affect your body’s growth, metabolism, and more, the same role that regulators play for plants. Regulators are absorbed by plants via roots, foliage, or by absorption into sapwood and “tell” the plant when it is time for them to grow, flower, or enter a state of dormancy. These chemicals are slow-acting and can take weeks to affect a plant.

While growth regulators can be used to prevent plants or trees from growing, these hormones differ from herbicides. Herbicides quickly kill all the vegetation with which the substances come in contact. These regulators limit the number of nutrients a plant uses, so the plant grows slowly.

Plant growth regulators can be broken down into two main types, with specific chemicals falling under one or the other:

• Promoters enhance and stimulate cell division, plant cell enlargement, flowering, fruiting, and seed formation.
• Inhibitors prevent growth and promote dormancy and abscission (shedding) in plants.

Examples of promoters include auxins, gibberellins, and cytokinins. An example of an inhibitor is abscisic acid. Each of these growth regulators affects specific processes within plants.

Auxins are hormones found in shoot and root tips that promote cell division and stem and root growth. This chemical is used to help stimulate cell elongation by increasing cell walls, thus helping promote the plant’s stem growth. Auxins can also drastically affect plant orientation by promoting cell division to one side of the plant in response to sunlight and gravity. Plants grow in the direction necessary to absorb the most sunlight possible, so if sunlight only shines on the western side of a plant, auxin will collect on the shady eastern side to promote growth.

Gibberellins affect many aspects and processes within a plant, such as germination, flowering, and flower development. One of the uses of gibberellins in plant health care is growth and germination control. Low hormone concentrations can increase the speed of germination and stimulate cell elongation, so plants grow taller.

Like auxins, cytokinins are chemicals that promote cell division and the formation of new leaves. Generally, cytokinins help initiate flower budding and encourage lateral growth so that a plant becomes “bushier,” or more expansive in size. In addition, if a plant has increased absorption of water and other minerals, then cytokinins can help stimulate the metabolism of young shoot cells, encouraging growth.

Unlike the plant growth regulators mentioned above, abscisic acid is an inhibitor, slowing down growth, metabolism, and seed germination. In addition, abscisic acid helps regulate dormancy and shedding, particularly as a response to environmental conditions and stresses, such as droughts or extreme temperatures. The chemical also plays a vital role in increasing stress tolerance and generally improving a plant’s ability to respond to stress.

While ethylene can inhibit plant growth, this chemical is sometimes used as a promoter. Like abscisic acid, ethylene promotes leaf and flower shedding but can also be used to break the dormancy of seeds and promote flower bloom.

As mentioned above, each of these plant growth regulators affects different aspects of plant growth and development, and each is needed in different amounts based on the conditions and issues a plant faces. For example, if a plant is too short, a certified arborist or plant health care expert can provide concentrations of gibberellins to promote growth and help make the plant taller. Likewise, if a flower needs help blooming, a plant health care specialist can use chemicals such as cytokinins or ethylene to encourage blooming. All of these hormones and chemicals can be used to help plants grow in a particular way while maintaining the plant’s overall health and biology.

If you want to keep your plants and trees healthy and vibrant, contact Burkholder PHC. We offer many plant health care services, such as plant growth regulators, pest control, and soil care. In addition, our team of specialists has years of experience maintaining landscapes in the Main Line area. For more information about our services, request a free consultation today.

Phytophthora root rot is a common fungal disease that afflicts many plants outdoors and indoors. The condition causes rotting within the plant stem and roots. Young plants are particularly prone to the adverse effects of the disease, but many plants, trees and shrubs can be affected. This article will focus on the causes, symptoms, and potential remedies that may help treat the root rot.

Phytophthora is a genus of parasitic microorganisms that cause a range of diseases in plants, particularly in the roots. The genus includes about 140 species. They are oomycetes, as are all water molds, and like other members of this group they have microscopic sporangia (spore capsules) that are produced in great numbers by germination of endospores. Certain conditions are more conducive to disease development, namely if the soil contains too much moisture and if the soil temperature is above 60 degrees Fahrenheit. In these conditions, oospores germinate and produce additional spores. These spores then infect a plant’s root and rot the system over time. More spores form in the residue, and the entire cycle repeats, infecting other plants.

Some of the standard and most visible symptoms of Phytophthora root rot include the following:

• Leaves that turn dull green, yellow, or in some cases, red or purple
• Dark brown or black discoloration of the stem that extends up from the root/soil line
• General wilting of the leaves and branches

Other symptoms depend on the plant that is infected. Trees, for example, can have dark sap oozing from the trunk. Another symptom is reddish-brown streaks in the bark tissue. Signs of the disease can also appear on single leaves or branches of a tree and then spread to others.

Water and drainage are among the most important factors when managing or preventing Phytophthora root rot. First, plants need the correct amount of water, as overwatering (to the point of creating standing water around the base of trees or other plants) facilitates growth of this fungal disease. Second, proper drainage, which can be accomplished by breaking up compacted soil, is necessary to prevent excessive moisture in the soil.

Chemical controls can also be used in conjunction with water and drainage management. Fungicides need to be applied carefully and with professional guidance to maintain the health of other plants and the overall landscape. Another factor to consider is removing the infected plant. Removing an infected plant may be necessary to prevent the disease from spreading to other plants nearby. This is best done in winter since oospores prefer warm temperatures and are less likely to infect other plants.

If you are considering planting new plants in your landscape, we advise you to choose plants resistant to Phytophthora root rot. Below are 3 plants that are resistant to the fungal disease and native to Pennsylvania:

• Summersweet (also known as “Tom’s Compact Summersweet) a compact variety of flowering shrub that produces upright, candle-like, 6-inch-long white flower spires in summer.
• Sweetspire – a rounded, spreading, fragrant shrub with drooping spires of fragrant white flowers.
• Eastern ninebark – a deciduous shrub that grows 6 to 10 feet tall and wide, with green leaves 1 to 3 inches long. Small, pink-white flowers bloom in spring and red fruits appear in fall.

By planting flowers that are resistant to this fungal disease, you can prevent your landscapes from ever being afflicted.

If your plants show symptoms of Phytophthora root rot or other diseases, contact Burkholder PHC. Our team of experienced, qualified plant health care experts will evaluate the health and condition of your plants, diagnose the problems, and provide you with the recommended treatment options to keep your plants healthy and vibrant. Our proactive and holistic approach helps encourage and maintain the conditions that are best for your landscape. Contact us today for a free consultation.

There is consensus among plant health care professionals that the complex of insect and disease pests in landscape plants is becoming more explosive, harder to predict, and more difficult to manage. As invasive pests like Asian longhorn beetle (1998), brown marmorated stink bug (1998), emerald ash borer (2002), and spotted lanternfly (2014) have been brought in through the back door of global trade, attention has been drawn away from many old-school native pest groups, allowing some to catch a foothold in landscape plants and become increasingly problematic. No landscape plant pests have expanded more in the past decade than scale insects, which have historically been kept in check by biological control agents (predators and parasites), kept at low levels by weather factors, or controlled by collateral effects of treatments targeting other pests. In fact, advances in the technology of pest control may be partially responsible for the increasing threat from this pest group, as fewer systemic and broad-spectrum chemicals are used for non-selective pest management in landscape plants.

Scale insects are an extremely broad and diverse group, made up of two basic subgroups: soft scale and hardshell scale (armored scale). Soft scales are fairly large (visible to the naked eye) and secrete sugary honeydew that forms black mold on the infested plant along with anything beneath. These insects may look like small bumps on twigs and stems and are most commonly located and identified because of the amount of mold that grows on their excrement, turning plants black. Armored scale are much smaller, often not visible to the naked eye, and generally shaped like tiny oysters. Armored scale are most commonly located and identified because of decline/dieback of individual limbs or white, waxy powder on interior stems. Scale insects do not move very much and spend most of their life securely attached to the plant like a tick or a barnacle. All species of scale insects feed on the vascular system of the plants, intercepting critical nutrients moving between leaves and roots, leading to rapid decline of the infested plant.

A majority of common landscape plant species have one or more species of scale insects that feed on them and can cause significant damage; in the 2021 field season, we identified and treated 18 species of scale on properties in Chester, Delaware, and Montgomery counties.

So…what can be done about scale insects in landscape plants? As with all of our integrated pest management (IPM) programs:

1. Inspect and diagnose to determine which pest species is causing the problem.
2. Assess the extent of the damage.
3. Determine the need for intervention.
4. Apply least-damaging control measures.
5. Evaluate results and determine the need for follow-up treatment.

With scale insects, there are challenges at each of these steps, from identification of the pest responsible to recognizing an array of plant injury symptoms and from determining the need for intervention to understanding what management tactics will provide the greatest control at the time of application.

Although scale insects are a very odd and very primitive group of pests, their behavior and physiology can make them very hard to control, prone to explosive population growth, and very damaging to landscape plants. We would recommend a professional evaluation this winter and spring to determine if properties are currently infested with or at risk of infestation with scale or other pests. The evaluation is free…and proper treatments can bring back the health, vigor, and curb appeal of any landscape. If you are not happy with the appearance of your landscape plants, give us a call!

The roots of a tree are vital to the health and appearance of that tree. Roots provide nutrients, water, stability, and more to keep trees alive and healthy, and any issues that negatively affect roots, in turn, affect trees. Girdling roots is one of the most common issues that trees in urban environments run into and can be a serious problem if left untreated. Below we discuss what root girdling is, what the signs are, and what you can do.

Girdling roots occur when the tree roots circle and coil around the base of the trunk rather than spreading outwards. Think about the effect of wearing a belt that is too tight around your waist and you get the idea of what tree roots do when girdled. Girdling restricts the flow of water and nutrients to the tree, making the tree weaker and more unstable. While maple and linden trees seem the most susceptible, girdling can happen to nearly any tree.

Girdling roots are a common problem for trees in urban environments due to the factors those trees face that trees in nature avoid and those issues are related to a lack of space for proper root growth. Improper planting or transplanting is a significant cause of root girdling. If a tree is in a container or burlap for too long, the roots will eventually circle the trunk or container. If those roots are also not loosened during the planting process, the roots become girdled.

The same issue can occur when a tree is planted in a hole that is too small: the roots have nowhere to spread and need to encircle the tree to maintain growth, which leads to girdling roots. Pieces of the planting container or other debris in the planting hole can also cause girdling. Heavily compacted soil and proximity to foundations, curbs, and other obstructions (which can hinder root growth) are common causes for root girdling. So because the issue is happening to the roots, you might think that spotting signs of root girdling could be difficult.

Spotting root girdling is relatively easy, as plenty of signs can indicate that a tree has girdled roots. The most obvious sign is an abnormal trunk flare. A tree trunk typically flares out and widens at the ground, but if a tree has girdled roots, the trunk may appear straight or narrow, looking more similar to a telephone pole than a tree. Roots circling above the soil line may also indicate girdling, as can sunscald or frost cracks visible on the trunk.

Because girdling roots prevent trees from getting enough water and nutrients, other possible signs include the following:

• Thin or sparse canopy
• Die-back in the upper tree canopy
• Wilting, scorched, off-colored (yellow), or smaller than average leaves
• Early fall color and leaf drop

The best solution for treating root girdling in your trees is to contact a landscape professional. Girdled roots can be removed, but removing them yourself may cause damage to the main stem. An experienced plant health care professional or certified arborist will know the proper technique to minimize damage. In severe cases, girdling compromises a tree’s stability, and as a result, the tree may need to be removed. Preventing root girdling involves knowing the best planting methods, from digging the right sized hole to knowing where to mulch, all of which plant health care professionals know.

If you want to keep your trees healthy and prevent girdling roots, contact Burkholder. We offer many landscaping services such as plant health care, irrigation, landscape design, and more. Our passionate team of landscape professionals has years of experience designing and maintaining refined landscapes in the Main Line area. For more information about our services, request a free consultation today.