boxwood care

Tips and Tricks for Growing Cleaner Plants

Creating a phytosanitary plan doesn’t have to be a daunting endeavor. There are many simple steps you can take to grow cleaner plants. Saunders Brothers has worked with many researchers and Extension agents to establish protocol to help prevent the introduction and spread of Boxwood Blight at their nurseries. Although this plan was designed with Boxwood Blight in mind, these practices will help growers produce cleaner, more successful plants.

Foot mats/baths:

Foot baths are located at every walkway leading to the Saunders Brothers office.

Foot baths are located at every walkway leading to the Saunders Brothers office.

One of the first and easiest steps to take is the inclusion of foot mats/baths for sterilizing shoes of anyone entering a growing area. These can be placed in greenhouses, worker common areas, and near offices. Having foot baths as a first line of defense minimizes the introduction of new pathogens to your growing area. Saunders Brothers uses foot mats at the entrance to all of their office and worker areas. Saunders Brothers uses Zerotol® 2.0, but a 10% bleach solution is also effective.

Disposable pant/boot covers:

Crews in the field nursery wear disposable suits when they are working on larger plants.

Crews in the field nursery wear disposable suits when they are working on larger plants.

Crews wear rubber boots that can be easily cleaned and disposable pants when moving between growing areas.

Crews wear rubber boots that can be easily cleaned and disposable pants when moving between growing areas.

An example of plastic pant and boot covers in the field.

An example of plastic pant and boot covers in the field.

Disposable pants and boots serve as a physical barrier between one’s clothing and the plants they are working in. If there are any spores or pests on the clothing, it is less likely they will migrate to the plants. Saunders Brothers employees wear disposable, plastic pant and boot covers while working in boxwood houses. Boxwood Blight spores can stick to tools and clothing moving from location to location, so instead of worrying about having fresh clothes, disposable pant/boot covers are the perfect solution.

This is also a great tool for landscapers that may visit many sites in a day. Instead of having to change or sterilize clothing, wearing disposable pant and boot covers greatly reduces disease or pest movement from site to site.

Sterilizing tools/equipment:

Pruning crews as Saunders clean their tools with alcohol between each house.

Pruning crews as Saunders clean their tools with alcohol between each house.

Even large equipment like digging machines are cleaned with sterilant between fields.

Even large equipment like digging machines are cleaned with sterilant between fields.

Sterilizing tools and equipment is an easy, practical step to take towards growing cleaner plants. It is a good practice to carry around a spray bottle of isopropyl alcohol. Research shows that a 50% isopropyl alcohol solution is effective at killing most plant diseases. Alcohol spray can be used to clean any handheld tools such as pruners, shovels, or trimmers. Other options of sterilants are a 10% bleach solution or Lysol® spray. Many researchers also recommend hydrogen dioxide products such as Zerotol® 2.0. Make sure to always check labels before you use any products. Most of these products are very user-friendly and are labeled to clean tools, equipment, or even surfaces.

Dragging a hose through a bed of infected plants and then moving it through a healthy bed could spread diseases. Taking an extra minute to spray the hose down with a sterilant could avoid a bigger cleanup in the future.

Cleaning Stations/Sectioned growing areas:

Cleaning stations in the field nursery.

Cleaning stations in the field nursery.

Cleaning station in the container nursery.

Cleaning station in the container nursery.

This tip takes a bit more planning than some of the other suggestions, but might have the biggest pay off if you ever run into a disease or pest problem. Saunders Brothers has set up both their field and container nurseries in sections. In the container nursery, boxwood are grown in specific locations separated by roadways. In the field nursery, areas are sectioned based on geography. Each section has a cleaning station that all employees must visit at they enter and exit. Cleaning stations are stocked with:

  • Disposable pant/boot covers

  • Trashcan

  • Boot bath and brush

  • 70% Isopropyl alcohol spray/liquid hand sanitizer.

  • High pressure water hose (field)

Crews using a cleaning station to rinse off their shoes and equipment.

Crews using a cleaning station to rinse off their shoes and equipment.

Upon entering and exiting the area each employee must:

Entering:

  • wear rubber boots, easily washed boots, or disposable boot covers

  • step in boot bath/wash boots

  • put on disposable pant covers

Exiting:

  • remove and trash disposable pant covers or spray pants

  • step in boot bath/wash boots

  • wash hands/ use hand sanitizer

  • rinse off tools, then spray with alcohol

This is an example of the sectioned boxwood production areas are at the containers nursery at Saunders Brothers.

This is an example of the sectioned boxwood production areas are at the containers nursery at Saunders Brothers.

The perks of setting up these sectioned areas is that in the event of an infection, you can quarantine one area, and continue production from the other locations. Consequently, each time a person or a crew enters a new area, they are cleaning off any potential pests or diseases.

Establishing cleaner growing protocol doesn’t have to be a daunting task. Taking some steps early on in production can help set you and your plants up for success while combating common pests and diseases. Consider these tips and find what works for you.

Benefits of Mulching Boxwood

Boxwood in the landscape with a think layer of mulch.

Boxwood in the landscape with a think layer of mulch.

Mulching is a common landscape practice that is used to suppress unwanted weeds, reduce evaporation from the soil, and encourage proper soil ecology and structure while being visually appealing. Recent research has also shed light that mulching can be an effective tool to aid in pest and disease management. Earlier this year, Virginia Tech published data from a two-year study showing that mulching can be a great tool to help prevent Boxwood Blight.

The experiment was set up in two locations, one being an old nursery in Low Gap, North Carolina and the other a residential landscape near Richmond, Virginia, both previously devastated by Boxwood Blight. This field trial consisted of both mulched and non-mulched treatments and was done for two years under normal environmental conditions. The goal of this study was to evaluate mulch as a physical barrier to prevent the soil inoculum from splashing onto healthy plants.

The fungal pathogen Boxwood Blight (Calonectria pseudonaviculata) produces heavy, sticky spores on diseased leaves that fall to the soil. There is no evidence to date of the pathogen attacking boxwood roots, so it was thought that providing a physical barrier of mulch would prevent the inoculum from splashing onto the leaves where the pathogen can affect the plant. The experiment used containerized ‘Justin Brouwers’ boxwood which are known to be highly susceptible to Boxwood Blight, that were rotated through mulched and non-mulched plots at 1-to-2-week intervals.

A freshly mulched bed of NewGen Independence® and perennials.

A freshly mulched bed of NewGen Independence® and perennials.

Results of the experiment showed clear distinction between the mulched and non-mulched plants. The mulching reduced the number of Boxwood Blight lesions by up to 97%! Even the scientists working on the project were amazed by the unbelievable difference that mulch made. Although for a long time it was thought that mulching boxwood plants was a bad idea but, this study shows that it can be an exceptionally effective tool for Blight control. Below you will find a downloadable PDF of these findings. Saunders Brothers Nursery worked with Chuan Hong and his team to provide plant material for the experiment.

Boxwood blight is a multi-faceted disease that can be overcome with smarter growing practices and understanding. Mulching has been proven to be another very simple and accessible tool that can help prevent this disease.

Boxwood Site Selection and Irrigation

Boxwood being used as a hedge in a landscape.

Boxwood being used as a hedge in a landscape.

Boxwood are known for low maintenance and longevity in a landscape, but in order to ensure such timelessness, it is important to select the best site for the plant. When properly planted and cared for, boxwood are easy to maintain. Paying extra attention at planting will ensure a flourishing plant for years to come.

In choosing the proper site, we recommend the following:

Several boxwood in a shady site.

Several boxwood in a shady site.

  • Choose the best cultivar based on size, shape, growth rate, maintenance, and exposure.

  • Take a soil sample and have it tested. Look for areas of good drainage with a pH in the range of 6.5-7.0.

  • Prepare a proper hole, making sure to plant the boxwood “high” with 2 inches of the root ball above the soil line. Be sure that water drains away from the plant and does not puddle near the root ball.

  • Water thoroughly at the time of planting and maintain adequate but not excessive irrigation through the first couple of years.

Once the boxwood is properly planted, it is very important to water it. A thorough soaking at the time of planting is essential. This will probably be the most important watering this plant will ever have. Make sure to fully soak the root zone.

Boxwood being irrigated first thing in the morning.

Boxwood being irrigated first thing in the morning.

Once this initial watering is complete, periodic watering should take place as needed. Allowing the root zone to dry between irrigation events will encourage root growth. We recommend approximately 1 inch of precipitation or irrigation per week for the first 1-2 years. Pay close attention during the hot and dry summer months, so that the boxwood does not stress. It is also important to pay attention that the plants have adequate moisture as winter approaches. In the Mid-Atlantic region of the United States, boxwood will continue to grow roots in the winter when the temperatures are still mild.

The arrows show holes on the drip tape where the irrigation water escapes.

The arrows show holes on the drip tape where the irrigation water escapes.

Here the drip tape sits on top of a bed of field plants.

Here the drip tape sits on top of a bed of field plants.

Drip irrigation is the ideal method for watering boxwood. Simple drip systems can be installed under the mulch and will offer thorough irrigation without wetting the foliage. In a drip system, water seeps from the drip tape without splashing. It enters the ground without puddling and conserves water. The rate of water from drip tape is very low, maybe a quarter of an inch per hour per emitter. Fungal diseases such as Boxwood Blight can be spread through water splashing that may occur with sprinkler methods of irrigation. If drip irrigation is not an option, make sure overhead watering takes place in the early morning, giving the leaves ample time to dry. It is important to never water boxwood in the late afternoon or evening because wet foliage through the night can lead to diseases and stress on the plant.

Raised beds ready for boxwood planting. It is very important that boxwood are planted “high” to avoid water pooling around the roots.

Raised beds ready for boxwood planting. It is very important that boxwood are planted “high” to avoid water pooling around the roots.

In 2018, Central Virginia had an annual rainfall of close to 90 inches, about double the normal amount. Boxwood throughout the region showed signs of stress, particularly those plants that were constantly in standing water. Whenever you plant boxwood, envision what the immediate landscape will look like after 3 inches of rain, and plant the boxwood in such a way that ensures water never puddles around the roots.

Giving added care before planting, boxwood are destined to succeed and maintain a timeless elegance in your garden.