Tips, Tricks, and Techniques
Written by: ELA Staff Zach McElgunn and Amy Nyman, Horticulture Outreach Manager, New England Botanic Garden at Tower Hill
This month, ELA takes some quick tips, tricks, and techniques from our Eco-Answers with an ELA Eco Pro, Q&A webinar series.
On August 3rd, ELA had the privilege to spend an hour of learning and discussion with Scott McPhee and Steven Vernon of Harrison McPhee Inc. (Millis, MA). With a combined roughly 47-years in the tree care industry, Scott and Steve’s collective expertise were tapped by ELA members over the course of this free-flowing conversation. Below are some of Scott’s and Steve’s recommendations regarding heritage-tree preservation, long-term arbor planning, the protection of trees in urban and suburban environments, and other topics which came up throughout our time together.
Thank you, Scott and Steve for your generosity in sharing your perspective with ELA! And also for the work you do every day to create and preserve lived-in environments that nurture a love and appreciation of the outdoors.
Thank you as well to ELA board member, Willow Cheeley, for coordinating Scott and Steve’s participation, moderating our discussion and keeping us on track throughout.
Soil Testing – ensuring an environment conducive to the long-term health and growth of trees:
- Reach out to a local/regional university or agricultural college to see if they offer soil testing services (e.g. the UMass Amherst Center for Agriculture, Food, and the Environment soil and plant nutrient testing laboratory; Penn State College of Agricultural Sciences soil testing services; etc.)
- Consider more intensive (and potentially more useful) services as well, which examine the soil for criteria beyond pH level, nitrogen, etc., such as Cornell’s Comprehensive Assessment of Soil Health (CASH) Framework
- NOTE: This more intensive service will likely carry a higher cost, as the “mid-range” service described by Scott and Steve runs about $150 per report, but there are downloadable free pdfs on soil health concepts, soil health assessment, soil health management, and other topics available online.
- Keep a longitudinal approach in mind when testing soil, as a single point in time can only provide so much actionable information → Soil testing should ultimately help generate a “narrative” of the soil’s health and development over a period of several years.
Communication & Land Stewardship – improving arboriculture knowledge in your community, and awareness of tree services outside of tree removal:
- Remain attentive to safety concerns (i.e. about trees damaging property) while correcting any misinformed underlying beliefs by those who are considering tree removal either on their own property or on public land in your community
- Suggest that the individual or entity considering tree removal undertake a formal hazard assessment by a certified arborist
- Discuss opportunities to engage in soil care, invigorating a tree’s root system, and providing physiological benefit to the tree
- Consider structural pruning or cabling to improve stability
Removing Invasive Herbaceous Plants (e.g. English ivy, liriope, Japanese stiltgrass) – are recommendations to throw 6-8 inches of mulch down to smother invasive species doing more harm than good?
- It’s definitely true that too much mulch can smother a root system, but what is “too much” is dependent on the strength, age, and health of the tree, among other factors.
- Potentially add cardboard or newspaper to the mulch to block out light invasive species receive
- Consider using an organic concentrated vinegar or fatty acid to remove foliage from invasive plants, and after foliage has been removed cover the plant with newspaper or cardboard
- NOTE: While 6 inches of mulch may seem like a lot, the potential damage to a tree depends on microorganisms within the mulch and soil, and how quickly the mulch breaks down
Composted Wood Chips – how much time, what type of wood, what is the impact?
- Fresh wood chips might have a carbon-nitrogen balance that isn’t appropriate for tree health, so maybe use wood chips that have been slightly aged.
- The reason for this is that bacteria may take nitrogen from the soil in their efforts to break down the wood chips, thereby depriving the tree in question from accessing that nitrogen
- Some people add a granular organic fertilizer to fresh wood chips in order to accelerate the decomposition process.
Trees in Foot-Trafficked Areas – species considerations
- Hearty trees like sycamores can stand up to compressed soil
- Honey locust can be quite durable as well (which is why they are one of the more common street trees in a downtown area)
- Gymnocladus dioicus (Kentucky coffeetree) & Sephora japonica (Japanese Pagoda Tree) are legume trees, which are durable as well
- Planting drought-tolerant shrubs around the base of trees could be an effective way to limit foot traffic while also increasing visual interest
- Planting other companion plants might bring beneficial insects to the tree, which could improve the amount and diversity of nutrients to which the tree has access.
Providing Water During Drought – large trees, old trees, frail trees
- Use a lower sprinkler to reduce the speed of evaporation
- In principle, strive for as deep of watering as possible, because surface roots (on grass for example) might absorb all of the water before it gets down in the tree’s root system
- Dig a shallow hole at the tree’s 12-o-clock, 3-o-clock, 6-o-clock, and 9-o-clock positions, and let a hose trickle in that spot for 45 minutes at a time.
- This will reduce evaporation and give the water time to penetrate down into the root system
- Consider using something to act as a surfactant (dishwashing soap for example) along with your water → add a few drops of dish soap into a gallon of water, shake it up, and use this to water around the roots
- The surfactant will allow the water to penetrate the soil more quickly and get into the root system
- Don’t fertilize trees during a drought using any fertilizer that contains nitrogen, phosphorous, potassium or anything with any sort of salt index
Planting Patterns – Trees in groups? Solitary trees? Canopy trees? Understory trees?
- Planting trees together provides mutual shade for root systems and mutual protection from wind
- There are also benefits from Mother Trees that nurture smaller trees when trees are planted in groups
- Stratification attracts different insects and animals, which can have the knock- on benefit of keeping invasive species down
- Consider using a growth regulator for mature trees
- The chemical that blocks growth hormones – originally designed as a fungicide, used in orchards, nontoxic – has seen a decent success rate with treating anthracnose in mature trees
- The growth regulator does not inhibit all growth, but rather forces growth down into the root system
Tips and Tricks for Autumn Planting from Amy Nyman:
- Cooler temperatures and more consistent moisture (usually) make autumn a great time to plant trees and shrubs.
- Perennials should be planted about a month before expected hard frosts.
- Watering is still necessary for two years to establish trees and shrubs.
- Gator bags make watering easier and more consistent.
- Able to visually evaluate the effect of autumn color in the design.
- Fall-blooming plants are available – and blooming!
Amy’s list of plants that have weathered the drought without hiccups
- Agastache ‘Blue Fortune’ (‘Black Adder’ not so much)
- Allium stellatum
- Amsonia hubrichtii
- Calamagrostis Karl Forster (not a favorite, I know)
- Fragaria virginiana
- Galllardia sp.
- Hibiscus moschuetos
- Perovskia atriplicifolia
- Pycnanthemum muticum
- Rhus copallinum
- Scabiosa sp.
- Scutellaria incana
Thank you, Amy for sharing your expertise and taking the time to compile these lists for ELA! If you have some helpful tips, tricks, or techniques you would like to share with our community for the upcoming season, please send them to firstname.lastname@example.org.