In the city, outdoor gardening space can be hard to find. Backyards are replaced by balconies, but this doesn’t mean you can’t still garden for pollinators. You just have to get creative about it. This National Pollinator Week, TPI has tips and tricks for how you can support urban pollinators with container gardening whatever your outdoor space looks like (even if it’s just a windowsill!).
1. Choose perennial native plants. Apart from a few species with deep taproots, many native plants will thrive in containers. Since they’re perennial, your plants will come back year after year, and support pollinators without any extra cost. Here are some good options that TPI has had success with:
swamp milkweed (Asclepias incarnata)
anise hyssop (Agastache foeniculum)
lance-leaf coreopsis (Coreopsis lanceolata)
smooth aster (Symphyotrichum laeve)
great blue lobelia (Lobelia siphilitica)
cardinal flower (Lobelia cardinalis)
blazing star (Liatris spicata)
virginia mountain mint (Pycnanthemum virginianum)
purple coneflower (Echinaecea purpurea)
Blazing star (Liatris spicata), aka gayfeather, is a favorite of pollinators and easily grown in a container! PC: Flickr, CC.
2. Combine plants with complementary bloom times to have the greatest impact. For your first container, try picking three plants: one that blooms in early summer, one in mid-summer, and one in fall.
3. Deep containers are your friend. Choose containers at least 16” deep to allow your native plants to build strong root systems and thrive for years to come.
4. If you only have space for shallow planters (<12” deep), annual or biennial native plants are a great option. These plants don’t invest in a deep root system and can survive in shallower soils. Black-eyed susan (Rudbeckia hirta), spotted horsemint (Monarda punctata), and partridge pea (Chamaecrista fasciculata) are three good choices.
5. Flowering herbs are also a great (and tasty) option for small spaces. TPI previously waxed the benefits of letting your herbs for pollinators, and the same applies here. Dill, lavender, thyme, mint, and cilantro are all popular herbs that do well in containers and favorites of pollinators.
Container herb gardens can be a win-win! Flowering mint feeds all sorts of pollinators, like this metallic green sweat bee (Agapostemon sp.), and you can enjoy mint leaves in sun tea and watermelon coolers! PC: Nick Dorian.
6. Water often. Soil in containers dries out faster than those growing below ground, and as your plants become root bound, they will need water more frequently. As always, water the soil rather than the leaves.
7. Don’t fertilize. Native plants are adapted to soils that are low in nutrients, and adding fertilizer will result in many big leaves and not many flowers. Amend store-bought potting mix with perlite and sand to create a well draining medium for your plants. Leave the manure and kelp fertilizer for your veggies!
8. Protect your container plants over the winter with 3-4” of leaf mulch, by moving your planter to a less exposed area, and potentially covering with a tarp. The key is to keep the soil warm enough so the roots don’t freeze through.
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.
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.***
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.
***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.
