Urban Boston Fall Pollinator BioBlitz!

This weekend, September 26-27, 2020, join TPI for a fall pollinator bioblitz! If you live in the city around Boston (east of I-95) get out during the weekend to observe pollinators—bees, butterflies, hover flies, wasps, and beetles—and post your sightings to iNaturalist. There will be so many insects to see, including monarch butterflies, bumble bees, paper wasps, goldenrod beetles, and more! If you’re not familiar with iNaturalist, see this guide for getting started.

During the bioblitz, TPI biologists will be scouring the flowers in our gardens on the Tufts University Medford-Somerville campus. We hope you’ll get out in your yard or neighborhood to look for pollinating insects, too. Your participation in this bioblitz will help TPI biologist better understand how gardens support pollinators in the city.

Never participated in a bioblitz before? Here are some tips to get you started:

No, you didn’t just find a murder hornet

TPI has received several inquiries about murder hornets appearing in Massachusetts. Rest assured, you did not find a murder hornet in New England.

Invariably, the giant wasps being reported are *eastern cicada killer wasps* (Sphecius speciosus). Though their name may be menacing, these native wasps are not out to get you, your pets, or honey bees.

Rather, they’re after cicadas. In late-summer, when the deafening choir of cicadas reaches its peak, cicada killers emerge. Males emerge first and are most interested in mating. In an effort to win the top female, males guard territories all day long and duel readily with similar-sized intruders.

Females, on the other hand, hunt. They track down and find adult cicadas (specifically, dog day cicadas that have short life cycles, not the periodical ones that remain underground for nearly two decades). Upon finding one, she paralyzes it with her stinger, hauls it back to the nest, and buries it in the long underground burrow she has prepared for her offspring. During her 3-4 week life, she is industrious: she will lay 10-15 eggs in all and provision each egg with 2-3 cicadas.

eastern cicada killer wasp carrying a cicada
Eastern cicada killer wasps hunt cicadas, not honey bees. PC: Judy Gallagher, Flickr

You can identify cicada killers by the combination of orange-black head and thorax and a black abdomen with broken yellow bands. They are 1.5–2 inches long, about the length of a piece of rigatoni. Females do have a stinger for paralyzing cicadas, but they’re docile and will not sting unless provoked. Adults are common in the US east of the Rocky Mountains and are around for only a few weeks each year to coincide with cicada activity.

Occasionally, you might find an entire nesting population of cicada killers. Typically, they nest near each other in sandy, well-draining soil found in disturbed lawns or golf course bunkers. Nests can be identified by the combination of a hole about the width of a nickel that’s preceded by a wide fan of soil.

cicada killer nest
Cicada killer nests are conspicuous. Look for a nickel-sized hole preceded by a wide fan of soil. PC: Sarah Zukoff, Flickr

If you want to discourage cicada killers from nesting in your yard, you can disturb the nest entrance or keep it wet since they prefer dry soils for nesting. Definitely don’t use insecticides. Chemical pesticides can persist for many years in soils harming other beneficial organisms in the process. Remember, these wasps play an important role in the checks and balances of our native ecosystems and help cut down on the incessant din of cicadas, so it’s in your favor to just let them be.

cicada killer wasp aggregation
Typically, cicada killers nests in dense aggregations. Each brown patch in the lawn is a cicada killer nest. PC: Chick Holliday, Wikimedia

If you spot a cicada killer, take the opportunity to watch it work. You might see a male guarding its territory or a female on the hunt. If you’re still enough (and resemble a tree), one might even land on you! Stay calm, and remember, they’re not out to murder you.

cicada killer on human hand
It’s hard work flying with a cicada! A female cicada killer wasp is taking a rest on the hand of former TPI member Max McCarthy.

Let herbs flower in your quarantine garden

As the heat of summer approaches, your quarantine garden will rely on insect pollinators to produce its bounty. Tomatoes. Cucumbers. Heaps of zucchini. This free ecosystem service—pollination—is often taken for granted, but it wouldn’t be possible without the help of insects: bees, butterflies, hover flies, beetles, and wasps.

To support these insect pollinators, you don’t need another garden. Simply let your herbs flower.

Herbs are a group of plants that have at least one organ (leaves, stems roots, flowers) that is tasty or medicinal. Leaves and stems get all the attention, while flowers often get overlooked, clipped away with the dead leaves and added to the compost. Not only are herb flowers almost always edible, but they also offer a veritable feast—nectar and pollen—to pollinators.

herb flowers
We most often eat the leaves and stems of herbs, like chives, thyme, and sage, but pollinators feast on the nectar and pollen from the flowers. PC: Timothy Vollmer, Flickr

Case in point: chive flowers feed sweat bees and carpenter bees after a long winter; the inverted flowering parasols of dill are a favorite of beneficial wasps and hover flies; and you’d be hard-pressed to find a flowering blade of lavender without a bumble bee. Moreover, flowering herbs teach a valuable lesson in pollinator gardening 101. Diversity begets diversity. To support all the pollinators that make your garden productive, plant diverse herbs.

Bumble bees are always attracted to the nectar-laden flowers of oregano. PC: Nick Dorian

It’s not hard to get started. Compared to pollinator-friendly native plants*, herbs are easy to procure. Seedlings are available for purchase at garden centers and many grocery stores in spring and summer.  

Herbs are also conducive to being grown in containers, making pollinator gardening possible anywhere, even on balconies or in window boxes. Herbs are forgiving to grow (sometimes downright invasive, another reason to use a container) and only require regular watering and some direct sun. And best of all? The strong flavor of the leaves that we enjoy in our cooking is despised by rabbits and deer.

Herbs are particularly conducive to container gardening. Here, the gardener has flanked orange tomatoes (center) with herbs. By letting their herbs flower, they will support bees that pollinate tomatoes. PC: greckor, Flickr

When picking out herbs for your garden, my recommendation may seem counter-intuitive: grow what you like to eat. Gardening for pollinators can be more involved, but it doesn’t have to be. All flowering herbs support pollinators. By selecting particular combinations of herbs to grow, however, you can maximize the benefits of your quarantine garden for pollinators. Here are four tips:

  1. Combine herbs that vary in flower shape (e.g., dill, lavender, borage, chamomile).
  2. Combine herbs that vary in fragrance (e.g, cilantro, basil, rosemary, lemon balm).
  3. Combine herbs that vary in size (e.g., thyme, chives, nasturtium, fennel).
  4. Combine herbs that flower in succession, from spring (e.g., chives, sage, rosemary) to early-summer (e.g. thyme, lavender) to late-summer (e.g., basil, oregano).

Next, put your herbs in the ground or in a pot with plenty of room to grow (6-8” between plants). Water them well at first, then a few times per week or whenever the leaves begin to wilt. If you already have herbs in your garden, even better! You’re ahead of the game.

In New England, thyme flowers in early summer and feeds many pollinators. It’s perennial, meaning it will feed pollinators year after year. PC: Nick Dorian

Harvest leaves and stems throughout the season (morning or early evening is best!). Use them fresh or dry them for later. A few of my favorite things to make with herbs: mint-watermelon cooler,  gnocchi with brown butter-sage sauce, and pesto potato salad.** With leftover pesto, I make pesto ice cubes to enjoy garden freshness all winter long.   

At some point during the growing season, your herbs will want to flower. The flowering time of the herb depends on its life cycle. For perennial herbs that come back each year, such as chives or sage, the plant will flower at a predictable time each year alongside your harvest. For annual herbs that die at the end of the growing season, such as basil or cilantro, the plant will flower at the end of summer or if it gets too cramped in its container. In both cases, the leaves and stems are still edible while the plant is flowering, but they will be tougher and less sweet than before.***

Honey bees love flowering lavender!

Letting your herbs flower is a simple, intentional act that sets in motion the dinnertime rush. Take time to notice your guests. Notice how bees push and reach over each other to get food on their plates, family style. How hover flies wait back for the perfect moment to land, so they can eat without being disturbed. How butterflies sip nectar, polite and upright, as if dining at a fine restaurant. Take pride that you’ve put food on their table, just as they have on yours.

*Flowering herbs are non-native, introduced by colonists. That means our native pollinators don’t share an evolutionary history with herbs and, therefore, don’t benefit as much from herbs as they do from native plants. If you’re interested in adding native plants to your garden, check out our handout for recommendations on what to plant.

**Pesto potato salad

  • 2 cups quartered baby potatoes
  • 1T paprika
  • 2T chopped rosemary
  • 1c green beans, cleaned and cut into 1in pieces
  • 4 roma tomatoes, halved
  • 2c fresh basil, loosely packed
  • 2T sunflower seeds
  • juice of half a lemon
  • 1/4c grated parmagiano regiano
  • 1/2c extra virgin olive oil + 2T extra for potatoes
  • 1 large or 2 small cloves garlic
  • salt and pepper to taste

Preheat oven to 400˚F. Toss quartered potatoes in olive oil, salt, pepper, paprika, and chopped rosemary and roast in oven for 35-40 minutes. Meanwhile, blanch green beans in boiling water for 60 seconds, then shock immediately in ice water. Set aside. If possible, grill tomato halves for 8 minutes, until charred and cooked. If not, place in the oven with potatoes for the final 10 minutes of roasting. Dice tomatoes and toss the body of the salad to mix. Dress with pesto (see below). Enjoy!

Earlier that same day (or while potatoes are roasting), prepare pesto. Process together basil, sunflower seeds, lemon juice, garlic, cheese, and s&p, slowly drizzling olive oil into the blender to emulsify and incorporate. Adjust seasoning to taste. 

Pesto potato salad features basil.

***Nick’s tip: If you want to delay the flowering of your herbs, perennial or annual, clip off incipient flower buds. Do this when the buds are small.