Urgent Update for Ann Arbor Landscape: Box Tree Moth Quarantine and Revised Hemlock Woolly Adelgid Quarantine

August 10, 2023

As a leading landscaping company in Ann Arbor, Twin Oaks Landscape remains dedicated to staying current with industry developments. We want to bring your attention to a recent announcement by the Michigan Department of Agriculture and Rural Development (MDARD) regarding the box tree moth, an invasive species with the potential to harm ornamental boxwood plants.

Quarantine Details

Effective since April 10, 2023, the original quarantine encompassed Lenawee, Washtenaw, parts of Monroe, and Jackson counties.

Expansion of Box Tree Moth Quarantine

The Box Tree Moth quarantine area has undergone an extensive update, now encompassing Clinton, Eaton, Ingham, Jackson, Lenawee, Livingston, Monroe, Oakland, Washtenaw, and Wayne counties. This crucial measure restricts the movement of boxwood plant parts and nursery stock outside the quarantined area and aims to curb the spread of the invasive pest.

Importance of Vigilance

Be vigilant for signs of stress in your boxwood plants, like yellowing or missing leaves, which could indicate an infestation. Twin Oaks’ landscape maintenance plan includes vigilant monitoring during monthly bed maintenance visits.

Reporting Infestations: If you suspect box tree moth infestation, report it online at www.Michigan.gov/ReportBTM. Your action can prevent further spread and safeguard Michigan’s green industry.

For comprehensive information on the quarantine and effective solutions, visit www.aphis.usda.gov/planthealth/box-tree-moth.

Revised Hemlock Woolly Adelgid Quarantine

In a related development, the Michigan Department of Agriculture and Rural Development (MDARD) has announced a revision to the State of Michigan’s interior hemlock woolly adelgid quarantine, effective from August 1, 2023. This revision includes the addition of Benzie and Manistee counties, along with a portion of Washtenaw County in proximity to the Nichols Arboretum. The previous quarantine encompassed Allegan, Mason, Muskegon, Oceana, and Ottawa counties.

Under this quarantine, the movement of hemlock and tiger-tail spruce trees, forest products, and nursery stock within the quarantine areas is regulated, subject to exceptions, to prevent further infestation spread.

Mike Philip, Director of MDARD’s Pesticide and Plant Pest Management Division, emphasized the need to protect Michigan’s 170 million hemlock trees due to their impact on streamside habitat conditions and overall stream health. He highlighted the potential risks of losing hemlock trees, including elevated water temperatures and increased soil erosion in streams.

Trees infested with hemlock woolly adelgid can be reported through various channels, including:

• email (MDA-Info@Michigan.gov)
• phone (MDARD Customer Service Center at 800-292-3939)
• online reporting through the Midwest Invasive Species Information Network
• the MISIN smartphone app

The expansion of the quarantine area aims to curb the spread of hemlock woolly adelgid and its potential to cause substantial losses in various industries, including timber, lumber, nursery, landscaping, Christmas trees, and tourism. The goal is to prevent the pest from moving to new areas within the state and to slow its spread within current infested regions.

To facilitate accurate reporting, be prepared to provide the location of infested trees and accompanying photographs of infested branches. The updated hemlock woolly adelgid interior quarantine details can be found at www.Michigan.gov/HWA. For suspected quarantine violations, report to MDARD-NurseryCE@michigan.gov. For comprehensive information on invasive species in Michigan, visit Michigan.gov/Invasives.

Exploring Alternatives for Boxwood and Hemlock: A Range of Evergreen Options

The emergence of an invasive pest has prompted both landscape companies and homeowners to reconsider their choices for planting. While the classic boxwoods and hemlocks face the threat of replacement, there are several appealing alternatives that can maintain the charm of your landscape. Here, we present a selection of suggested replacements that can bring both beauty and resilience to your outdoor spaces.

1. Mugo Pine (Pinus sylvestris) The adaptable Mugo Pine presents an excellent choice, provided that poorly drained wet soils are avoided. This versatile evergreen can be shaped to resemble the elegance of boxwoods, with options to maintain a short and rounded form or to nurture a taller and more slender silhouette reminiscent of ‘Hicks’ Yew, albeit not as dense.
2. Holly Varieties (Ilex) Embrace the diversity of Ilex varieties, where both male and female plants are required for the delightful emergence of flowers and berries. Consider combinations such as Ilex x meserveae ‘Blue Prince’ + ‘Blue Princess’ or Ilex x meserveae ‘Blue Boy & Girl’. English Holly now offers ‘Combo’ forms, grafting male and female plants together, with ‘Berri-Magic Royalty’ standing as a notable example.
3. Inkberry (Ilex glabra) and Japanese Holly (Ilex crenata) Diversify your choices by exploring Inkberry, Ilex crenata (Japanese Holly) varieties, and even the deciduous Michigan Holly Ilex verticillata. Keep in mind that these alternatives might require less frequent planting, as they can develop broader and taller dimensions compared to traditional Boxwoods. However, the advantage lies in their easy manageability through regular pruning and shearing.
4. Euonymous Creepers and Climbers For a low-maintenance yet visually striking option, consider Euonymous. Varieties like E. fortunei ‘Emerald Gaiety’ and E. fortunei ‘Emerald n Gold’ provide elegant low mounding features that can add a unique touch to your landscape.
5. Shade-Loving Evergreens Rhododendron, Laurel, Pieris, and Azalea Elevate your landscape’s aesthetic by incorporating Rhododendron, Laurel, Pieris, and Azalea. Flourishing in shady and sheltered spots with acidic soils, these evergreens bring a touch of elegance to shaded areas.
6. Arb, Juniper, and False Cypress Varieties Diversify your landscape palette with the inclusion of Arb, Juniper, and False Cypress options. The Thuja occidentalis (Arborvitae) and various Juniper varieties, such as J ‘STAR POWER’ or J SC ‘SKYROCKET’, provide tall/narrow uprights or shrubs. Explore Juniperus shrub varieties like J. ‘Blue Star’, ‘Grey Owl’, ‘Gold Coast’, and ‘Broadmoor’ for an array of color possibilities that thrive in mostly sunny, well-drained environments. Meanwhile, the captivating Chamaecyparis spp. (False Cypress) family offers unique hues ranging from dark green to vibrant lime and yellow, catering to different preferences and landscapes.
7. Specialty Evergreens and Deciduous Alternatives Delve into the realm of Specialty Evergreens, including options like Weeping Spruce and grafted evergreens. While availability and pricing may vary, incorporating these ‘Specimen’ plants can significantly enhance your landscape’s visual impact.

Beyond the realm of evergreens, countless deciduous shrubs stand as suitable substitutes for boxwoods and yews. The world of plants offers a vast array of choices to explore and consider.

Our specialists are poised to guide you through the process of making the best choices for your unique landscape needs.

From classic alternatives to innovative selections, we’re here to help you craft a resilient and captivating outdoor environment while remaining dedicated to keeping you informed about industry trends. Stay informed. Stay green. Twin Oaks Landscape.