Tallamy-inspired Q&A

So many great questions were asked during the Question and Answer period, there wasn't time to address them all live. We have since compiled them into three groups by topic (plants, insects & birds, and management) and asked our in house experts to share their knowledge and suggestions. These are the management topic questions and answers.

What do you think of using cinnamon/clove/mint oils to deter deer and repel ticks and mosquitos?

These are a non-toxic approach to keeping some pests out of your yard. However, as much as they are likely to repel those pests, they are likely to repel pollinators and other beneficial insects too.

I find lots of caterpillars on my native viburnum, consuming lots of the leaves. I used an insecticide. Should I have let them continue? Would my plants have survived? I have seen a ladybug but no birds eating my these little green caterpillars.

Those were Viburnum Leaf Beetles. These beetles will completely defoliate a shrub, but it’s unlikely they will kill a shrub unless this happens for three to four years in a row. Thankfully, these beetles seem to move through an area one year and then are gone the next, so your plant will be able to recover. Here is a link to a Cornell University webpage with helpful information on managing these invasive pests. Insecticide use always kills the good bugs along with the bad bugs, which creates additional problems.

We have our oaks sprayed for winter moth and our hemlocks sprayed for aphids. Should we stop? What about grub control in the lawn? Without it, it looks like we just have a dirt patch.

Winter moth (Operophtera brumata) has been a problematic pest for a variety of native deciduous trees including white oak and maples. They have been such a problem because when they were accidentally introduced here from Europe, their specialized natural predators were not brought along with them. This created a scenario where their numbers were able to increase to the point of really damaging plants. Many people turned to insecticides to temporarily control them each year. Thankfully, a specialist parasitic fly that attacks winter moth caterpillars in its native geographic range was identified and successfully established in parts of New England over the past 15 years. It seems to be providing decent biological control of winter moth here in eastern Massachusetts now. More information about this biological control program can be read here. Hemlock wooly adelgid (not aphid) (Adelges tsugae) has a similar origin story. It was accidentally introduced here from Japan and became a major problem because of lack of population control by its natural predators. Research is underway to find a biological control solution, about which you can read here. As for lawn care and grub control--this was the topic of our March 25, 2021 talk with Chip Osborne! You can watch the recording here. He addresses other potential causes of poor grass growth and also grub control.

What do we do about the rabbits? Especially rabbits eating sunflowers. And also about deer browsing?

A couple nontoxic deterrent sprays are Deer Stopper and Deer Scram. Both of these products work for about a month. Rabbits are hungry at the start of the season and will eat almost any young shoot, but if you can protect plants with wire fencing until they grow above a certain height, rabbits tend to leave them alone. I also recommend trying plants that aren’t appetizing to rabbits and deer, although that list is becoming smaller every year. If you have a large property and many valuable plants, I would recommend a deer fence. Here’s an article with some plant recommendations.

What do you think of using glycophosphate and other herbicides for invasive species control?

Even though there have been no direct links between using glycophosphates and human diseases, using herbicides or plants warrants extreme caution. When you feel you must use them, the most focused application--painted on individual plants--will have the fewest unintended effects. Glycophosphates can live in the soil for at least six months, and food crops should not be planted in the area where herbicides are used. Mechanical methods for getting rid of invasives like knotweed, though labor-intensive, cause less harm to the soil and surrounding plants. Another approach to removing invasive plants is repeated removal of regrowing plant tissue--over time their energy reserves are depleted, weakening them to the point of removal.

How did Cindy Tallamy get rid of the invasive plants all over your property? Even in a small area, it feels like a losing battle.

Cindy Tallamy, according to Doug, repeatedly went after the invasive and removed them, and for some, she painted their stalks with herbicide. We need to realize invasives have been around for a long time, and we are just noticing them after they have gotten a strong foothold in the habitat. It will take time and persistence for their removal.

What do you do for light pollution from a streetlight very close by? It's probably killing a lot of insects.

Nighttime light pollution is a killer for insects--attracting them to the light distracts them from seeking food and mating. This shortens their lives and reduces their success at reproducing. Depending on how adaptable your town’s streetlights are, the hue (color) of the light can be changed to be in the more yellow range and brightness may be able to be somewhat decreased without compromising road safety. This can help the problem somewhat. Reach out to your town to make inquiries. What you can do on your own property is to make sure any external lights are on a motion sensor rather than left on all night, and use bulbs in the warmer (2700K or less) end of the spectrum. You might also consider growing tall plants near that streetlight, like a living screen, to provide nighttime shade for the rest of your property. That’s a longer-term solution though. A great source of information is this recent talk by scientist James Lowenthal on The Effect of Light Pollution on Pollinators.

Should we use mulch in our natural landscape?

Mulch can be helpful when starting a new garden bed. Wood mulch isn’t necessary. Leaf mulch saved from the garden works well. Leaf mulch is now available for purchase too. Ideally, the goal should be to cover bare ground with plants, which becomes your natural living mulch. While bark mulch helps the soil retain moisture and offers weed control, it does not provide the ecological benefits of plants. Plants can retain moisture, alleviate weeds, and provide habitat and food for native insects and wildlife.

Have any MA municipalities committed to only planting native species for street trees?

The only one that we’re aware of is the City of Somerville, which just adopted a Native Species Ordinance on March 17, 2021, culminating more than three years of effort. The ordinance requires 100% native species in riparian areas, the Community Path, bioswales, and other defined areas; 75% native species in parks; and 50% native species for street trees. The lower-than-100% numbers reflect the desire of city leaders for flexibility in light of a number of factors. For example, street trees must endure a harsh environment including road salt and air pollution--conditions few native species can handle. They hope to increase these numbers over time.

I live in a place where the grounds contractor sprays herbicides and insecticides and the watering system takes water from a well on the property. Also there is a large marsh abutting the property. How do I talk about the issues Doug highlights with the local managers?

It’s a process of educating contractors and landscapers. If wetlands are abutting the property, there should be limits to what pesticides can be used right next to them, but that would not apply to the rest of the land. Talk with your neighbors, share our website and the Tallamy talk with them, perhaps set up a zoom meeting to express your concerns. Many people are concerned about wildlife, but they are not informed about what is happening right outside their own front doors. Good Luck!

How can one counter the mindset of most suburban homeowners in which taking good care of their property means killing carpenter ants, woolly adelgids, termites, winter moths, etc.?

There’s a balance to strive for between cultivating the natural ecology of your neighborhood and targeted pest management to protect your home. Education, outreach, and leading by example are parts of this cultural shifting process. We’re so glad you asked the question though, as that’s the focus of Lexington Living Landscapes! Join in on our events, our mailing list, and volunteering opportunities. Reach out to us with ideas (lexlivingland@gmail.com). We’d love to hear from you.