gardening

The 5 best ways to make your yard pollinator friendly

by Atticus Murphy

Planting a pollinator garden is all the rage these days, but if you’ve never gardened before, it may seem like a daunting task. Don’t worry, it doesn’t have to be complicated! You can support pollinators in your yard by taking several easy and important actions. Tufts Pollinator Initiative has distilled it down to the 5 most important actions you can take today!

1. Plant a diverse set of flowering plants

Diversifying the flowers in your garden is the best way to support the most types of pollinators. Shoot for diversity on all levels: color, flower shape, size, and, most importantly, bloom time. Each pollinator species might only be active for a few weeks and visit a small number of plants, so adding flower diversity throughout the year will almost always boost your yard’s pollinator diversity (and give you blooms year round!). A good place to start? TPI’s top 10 flowers for bees!

Diversity begets diversity: we’ve planted over 15 flowering species at our campus gardens and seen over 115 species of insect pollinators!

2. Add woody plants like trees and shrubs

Native trees and shrubs make excellent additions to pollinator gardens because they provide resources that herbaceous, perennial flowers often don’t. For instance: many native trees and shrubs bloom early in spring, at a time when few other plants are blooming on the landscape. In addition, trees and shrubs provide homes for solitary bees and many butterflies depend on tree leaves to complete their life cycles. As a bonus, trees and shrubs require very little maintenance after their first few years and provide shade for decades! To help you pick, check out TPI’s top 10 trees and shrubs for bees.

Unequal cellophane bees (*Colletes inaequalis*) depend on pollen and nectar from early-blooming red maple trees to complete their life cycles.

3. Grow native plants

To support our native pollinators, grow native plants. Our native pollinators have been in relationships with native plants for thousands of years, and sometimes have evolved such a picky diet that only one or a few native plant hosts will do. Avoid non-native ornamental plants (esp. doubled cultivars) like petunias and impatiens–they either offer unsuitable food resources, or have been bred to offer no pollen and nectar whatsoever. Compared to traditional ornamental plants, native plants can survive is less than ideal soils and periods of droughts, while still filling your garden with bursts of color. Pick up your locally-grown native plants at TPI’s summer plant sale!

fall bees fueling up on new england aster before winter — Native bees love native flowers like New England aster.

4. Minimize herbicide and insecticide use

It’s simple: to keep insect pollinators around, don’t apply pesticides. Herbicides kill the flowers that pollinators use for food. Leaving weedy flowers (“weeds”) to bloom creates abundant and diverse resources for pollinators. And insecticides like neonicotinoids are deadly for pollinators: remember, anything that kills a mosquito almost certainly kills a bee. Even if you apply these chemicals to a separate area of your yard, they have a high potential of running off into the surrounding pollinator friendly areas. Stick to hand weeding problem plants whenever possible and try handling pesky insects in chemical-free ways like limiting standing water or having nests removed.

5. Mow remaining lawn infrequently

Conventional turf lawns are fun play spaces, but monocultures of grass do not support pollinators, so it’s always best to limit the amount of lawn on your property. For any lawn that you keep around, one of the most impactful things you can do is to mow as little as possible. Even going from mowing weekly to mowing every other week leads to dramatic increases in the number of pollinators and flowers found in lawns. You don’t need to let the lawn look truly wild to achieve big benefits either! Leaving a margin of unmowed grass around the edge can provide valuable nesting habitat for bees and low-growing flowers like white clover.

By mowing your lawn less frequently, you can support native pollinators like bicolored striped sweat bees *Agapostemon virescens*!

Following these simple steps can help you take big strides towards making your patch of the urban landscape a haven for pollinators. One of the most rewarding things about implementing steps like these is that you are nearly guaranteed to see returns after just a small amount of investment–if you plant it, the bees, butterflies, wasps, and hover flies really will come. Happy gardening!

To learn more, check out our publication on pollinator gardening produced in collaboration with Tufts CREATE Climate Solutions.

cultivate

Pipevine Swallowtails and the case for caterpillar gardening

When you think of gardening for pollinators, you most likely think of beautiful flowering plants which attract bees, butterflies, and other insects by offering copious amounts of nectar or pollen. But flowers cannot give all pollinators the food they need. Butterflies in particular can be very picky when deciding what to eat when first starting out their lives as caterpillars. Most butterfly species have evolved to specialize feeding on one or a handful host plants. In a sense, when it comes to supporting butterfly communities, providing ample host plants for these soon-to-be-butterflies could be just as beneficial as planting nectar flowers for adults!

Pipevine swallowtail eggs are laid in small clusters so that when they emerge, these caterpillars work together eating leaves in small groups

The Pipevine swallowtail Battus philenor is one butterfly that benefits tremendously from the gardening of its favorite plant, Pipevine Aristolochia, after which it is named. Both Pipevine and the butterfly with which it shares its name is native across eastern North America, including Massachusetts. The plant itself is highly toxic and could cause severe kidney problems or even cancer if ingested by humans, but Pipevine swallowtail caterpillars could not care less.

These caterpillars have evolved not only to cope with the toxins in the plants, but to actively seek them out. Pipevine swallowtails, like many other butterflies, including Monarchs and their beloved milkweed, acquire the toxic chemicals present in their host plant and sequester them. As caterpillars they build of reserves of this chemical making them unpalatable to potential predators for the rest of their life. This is part of the reason many butterflies display such bright and captivating scales – it can be a signal to predators that nothing good will come from eating them.

In the right conditions Pipevine can scale great heights clinging to trees or other supports

Though these caterpillars cannot get enough of Pipevine, the adult swallowtails themselves do not nectar on the flowers it produces. Pipevine, like the name suggests, produces curved flowers that resemble a smoking pipe which is not conducive for a butterfly proboscis. Dutchman’s pipe Aristolochia macrophylla, is the most common species in eastern North America, and produces small tubular flowers with a small circular entryway. Into that entryway go flies which are actually attracted to the flower’s fragrance. Upon entering the narrow pipe, the flies get a little stuck, catching some of the flower’s pollen and carrying it with them until they end up in another flower which they help fertilize. After fertilization, the plant produces great seed pods which, when rooted and grown, will provide more food for those hungry caterpillars.

Before you start thinking this toxic, fly-attracting plant might not be the right fit for your garden, consider that Pipevine has been an immensely popular ornamental plant since Victorian times. It is an ideal option for trellises, fences or pergolas, providing plenty of shade when mature! If you are interested in attracting these beautiful butterflies to your home or garden in the future be sure to water your Pipevine as it needs lots of water and give it a place to climb. Be sure, too, to get Aristolochia macrophylla specifically, as some species will not support these caterpillars or might even be invasive – moreover macrophylla will provide the best shade (it is given the Greek name meaning ‘large leaf’) and will attract some marvelous butterflies looking for the right place to lay their eggs.

Adult Pipevine swallowtails have a remarkable coloration, with black and iridescent blue wings that have orange and white spots on the underside (Photo credit: John Flannery)

educate

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:

Combine herbs that vary in flower shape (e.g., dill, lavender, borage, chamomile).
Combine herbs that vary in fragrance (e.g, cilantro, basil, rosemary, lemon balm).
Combine herbs that vary in size (e.g., thyme, chives, nasturtium, fennel).
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.***

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.

***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.