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How to stop bunnies from eating your pollinator garden

Don’t be fooled by extreme cuteness: bunnies are every pollinator gardener’s nightmare. You spend precious time and money planting a native garden to feed pollinators, only to end up feeding bunnies instead. In the TPI gardens at Tufts, we face our fair share of bunny herbivory. But, we’ve also learned a few strategies for combating hungry rabbits, including a list of which plants rabbits avoid entirely. Read on to learn our tips for how to bunny-proof your pollinator garden, and visit our native plant sale in mid-June to pick up plants that will thwart the rabbits!

With a little preparation, your pollinator garden can feed more bees than bunnies PC: jjjj56cp, Flickr

1. Prioritize rabbit-proof plants

The single best way to avoid having your garden munched on by rabbits is to grow plants that rabbits do not like to eat. Over the past three years, we have kept track of the fates of over 30 different species of native plants in our gardens. Although many of them, in one year or another, have been munched on by rabbits, some species have been avoided entirely. Here is the list of plants from our garden that have never been eaten by rabbits:

When other plants become a light snack for rabbits, New York ironweed does not. Its stems are tough and fibrous (some might even say iron-like), and their leaves contain bitter chemicals.

Mountain mint (Pycnanthemum spp., e.g. P. virginianum, P. tenuifolium)
Anise hyssop (Agastache foeniculum)
Bee balm (Monarda spp., e.g. M. bergamot, M. punctata)
New York ironweed (Vernonia noveboracensis)
Foxglove beardtongue (Penstemon digitalis)
Golden Alexander’s (Zizia aurea)
Goldenrods (Solidago spp. e.g. S. sempervirens)
Wild senna (Senna hebecarpa)
Joe-pye weed (Eutrochium maculatum)
Boneset (Eupatorium perfoliatum)
Cutleaf coneflower (Rudbeckia laciniata)
Sneezeweed (Helenium autumnale)
Partridge pea (Chamaecrista fasciculata)
(most herbs*)

2. Avoid tasty plants

In a similar vein, a great way to make your garden bunny-proof is to not grow the plants that rabbits love. Here’s a list of plants from our gardens that fed more rabbits than pollinators, and which should be planted with caution:

Symphyotrichum spp.asters (S. novae-angliae, S. laeve, S. prenanthoides)
Blazing star (Liatris spicata, L. scariosa)
Wild false indigo (Baptisia spp.)
Cardinal flower (Lobelia cardinalis)
Swamp milkweed (Asclepias incarnata)
Purple coneflower (Echinacea purpurea)
Cup-plant (Silphium perfoliatum)
Black-eyed susan (Rudbeckia hirta)
Sunflowers (Helianthus spp.)
red columbine (Aquilegia canadense)
Culver’s root (Veronicastrum virginicum) — not always eaten

3. Create an unappetizing display by mixing plants

We’ve found that tasty plants are often avoided when planted among distasteful plants, so try to mix and match. This means your tasty asters stand more of a chance if mixed in with lots of distasteful mountain mints, ironweed, and goldenrods. Pollinators appreciate the diversity too—the more diverse your garden, the more kinds of pollinators you will attract! And, from an aesthetic perspective, inter-mixing plants means that any rabbit herbivory that does occur will be far less noticeable.

4. Protect vulnerable plants

Rabbits love eating the youngest plants. Often, young leaves have not yet accumulated as many distasteful chemical compounds as older leaves. In our gardens, for example, young emergent sunflowers (Helianthus annuus) and cup-plant (Silphium perfoliatum) are frequently nibbled as seedlings, but are left untouched when they are larger. By protecting young plants with fencing, your garden will have the blooms you want later in the season!

The same applies to woody plants and saplings, but for a different reason. Young wood is soft, sweet, and easily chewed by rabbits and rodents. Be sure to fence young saplings in their first years–especially over winter–to prevent girdling and other herbivory that can kill your long-term investment.

5. Use your local knowledge

Keep in mind that our lists of plants (both enjoyed and rejected) reflect the tastes and preferences of rabbits in urban Massachusetts, as well as the context of our campus garden. So, to make your garden as bunny-proof as possible, learn from experience. If bunnies in your neighborhood never touch the wood asters and swamp milkweed in your garden, then by all means, plant, plant, plant. Conversely, if the bunnies in your neighborhood have a penchant for anise hyssop, then definitely don’t keep planting while expecting a different result.

Do you have tips for thwarting bunnies in your pollinator gardens? Drop us a comment!

*Although we advocate for growing native, you can add fragrant, non-native herbs like lavender, rosemary, thyme, borage, and oregano to make your garden even more bunny-proof. The nasty compounds in most mint-family plants are quite distasteful to bunnies.

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How to pick cultivars for pollinators

by Emily Erickson

Spring has finally arrived in the Northeast, and it’s time to start planting your pollinator garden! Perhaps you have already picked out the perfect spot in your yard and started making a list of which plants to purchase. Once you reach the garden center, you may be in awe of the different varieties to choose from. At the same time, you are faced with a familiar dilemma: are all these varieties equally good for pollinators?

What is a cultivar and why should I care?

Unless you are going out of your way to buy your plants from a specialty nursery, chances are you are purchasing a “cultivar,” or a plant that has been bred for desirable traits like the number of petals, flower shape, or flower scent. Plant breeding is not inherently a bad thing: it broadens the diversity of species that you can grow in your garden by improving resilience against pests, drought, or poor soils. As a result, cultivars have become the industry standard. They can be identified by the single quotation marks in the name (ex. Marigold Alumia ‘Flame’).

While cultivars are great for people, they are not always great for pollinators. Native plants and their pollinators share a long evolutionary history, and many flowers have evolved particular traits that signal honest advertisements of a high quality food resources. For instance, the smell and color of wild geranium tell a bee that that nectar and pollen awaits and the dark lines on the petals help them to quickly locate their meal.

In contrast, cultivars have been removed from evolutionary history with insects; humans have bred cultivars in labs and greenhouses to meet our aesthetic preferences. And sometimes, by selecting for traits that we deem impressive, we inadvertently produce plants that broadcast false advertising. Recent work, including my PhD research, has demonstrated how cultivars—even ones that look quite visually similar—can vary dramatically in the abundance and diversity of insects that they are able to support^1–6, so it’s important to choose carefully.

5 tips for choosing better cultivars

But, how do you choose? Ideally, all ornamental cultivars would scored for pollinator attractiveness to help guide customers to select high-value plants for their flower gardens. A metric like this doesn’t yet exist, however, so we’ve distilled down some basic guidelines that you can use to identify the best plants for flower-visiting insects!

1. Avoid doubled flowers

Double-flowered varieties are those that have been selected for extra petals, such as in many roses, impatiens, chrysanthemums, and carnations. Often, this doubling comes at a cost: the reproductive florets (where pollen and nectar are produced) are converted to petals, meaning the flower no longer feeds pollinators! And, even if the plant is still capable of producing rewards, doubling often obstructs visitor access to those resources⁶. So, while doubled varieties are interesting to look at, they are best left on the shelves.

Avoid doubled cultivars like this *Echinacea* ‘Pink Double Delight’, PC: Wikimedia

2. Choose perennials and ‘nativars’

Monarch butterfly nectaring on *Rudbeckia laciniata* ‘Herbstonne’ PC: Emily Erickson

Recently, the commercial plant industry has shifted towards producing more cultivars of perennial plants, including many native species, or ‘Nativars’.⁷ These varieties are often rewarding to grow since they come back every year once established and they require less maintenance overall. My research found that many native and non-native perennial cultivars can be highly attractive to flower-visiting insects in the field. I even observed several rare and specialized species foraging on nativars! Some of the best pollinator-friendly nativars are also easy to find:

Oenothera ‘Fireworks’
Echinacea ‘Magnus’
Rudbeckia ‘Herbstonne’
Solidago ‘Fireworks’
Agastache ‘Blue Fortune’
Eupatorium ‘Gateway’

For tips on which native plants to source for your garden, check out TPI planting guides!

3. Choose cultivars that resemble wild types

A general guideline for selecting the best ornamentals is to go for cultivars that look most like the wild types. Of course, this is a subjective criterion, and there are many traits that we cannot readily perceive (such as scent or nutrition) that can influence plant attractiveness to pollinators. Still, in my research I found that pollinator attraction to the herbaceous perennial Catmint (Nepeta)—of which purple is the primary color found in the wild (Catmint is native to the Caucasus region)—was highest for purple compared to white cultivars. In other words, the less derived, the better!

Catmint ‘Walker’s Low’ that resembled purple parents was attractive to pollinators. PC Nick Sloff

4. Check the label

A major concern with ornamental flowers is the use of pesticides, particularly systemic neonicotinoids, during production. These pesticides can end up in the pollen and nectar treated plants and can have lethal and sublethal effects on visiting pollinators. Before you purchase a plant from the nursery, check the label to see if it has been treated with neonicotinoids!⁸

5. See for yourself!

One of the best ways to find ornamental cultivars that are attractive to pollinators is to walk through the garden center and notice which plants seem to be either getting the most pollinator visits or are visited by many different species! This will open your eyes to all the different pollinators that call our yards home and the wide array of plants that they like to use.

References

1.  Garbuzov, M. & Ratnieks, F. L. W. W. Quantifying variation among garden plants in attractiveness to bees and other flower-visiting insects. Funct. Ecol. 28, 364–374 (2014).
2. Erickson, E., Patch, H. M. & Grozinger, C. M. Herbaceous perennial ornamental plants can support complex pollinator communities. Sci. Rep. 11, 17352 (2021).
3. Erickson, E. et al. More than meets the eye? The role of annual ornamental flowers in supporting pollinators. Environ. Entomol. 49, 178–188 (2020).
4. Rollings, R. & Goulson, D. Quantifying the attractiveness of garden flowers for pollinators. J. Insect Conserv. 23, 803–817 (2019).
5. Marquardt, M. et al. Evaluation of the importance of ornamental plants for pollinators in urban and suburban areas in Stuttgart, Germany. Urban Ecosyst. 24, 811–825 (2021).
6. Corbet, S. A. et al. Native or exotic? Double or single? Evaluating plants for pollinator-friendly gardens. Ann. Bot. 87, 219–232 (2001).
7.   Criley, R. A. Native fashion. Acta Hortic. 1167, 1–10 (2017).
8.   Erickson, E. et al. Complex floral traits shape pollinator attraction to ornamental plants. In Review.

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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.