Gardening for Pollinator Diversity

Gardening for Pollinator Diversity

When designing our gardens, there are so many ways to support pollinators, but it all starts with the plants! That said, not all plants are created equal when it comes to pollinator value, and different pollinators have unique preferences that we can use to inform our plant choices. Keep reading for a few considerations you should keep in mind — plus some of our favorite pollinator plants for Portland gardens — to help you create a diverse pollinator paradise that supports bees, butterflies, hummingbirds, and more!

Quick Tips for Pollinator Gardening

Native plants are an important component of any pollinator garden, but that isn't to say non-natives do not offer any value. In fact, to cover a greater period of the year with blooms, you'll likely want to include at least a few non-natives — especially ones that bloom during the winter and early spring when food may be scarce. Additionally, you will want to incorporate flowers with various bloom structures to accommodate a variety of pollinators, from the tiniest bee to the largest butterfly. (More on that below!)

Even for non-native pollinator plants, species plants are the safest bet to provide with the nectar and pollen that they need to thrive. While extravagant forms of flowers are gorgeous to the human eye, in the process of selective breeding by humans, double flowers with extra petals often sacrifice reproductive structures like nectaries for floral oomph, so it's best to look for single-flowered varieties of plants where applicable. And in general, the closer to the straight species a plant is, the more pollinator value it likely offers.

Plants for Bees

While non-native honeybees are generalists that will visit a wide variety of flowers, many of our native bees have much more specific relationships with only a handful of native plants. And among our native bees, bumblebees tend to feed on the greatest variety of plants. This is something to keep in mind when out in your garden: Observe who is visiting your plants and try to incorporate plants that attract more than just honeybees.

Around the Nursery, we notice that many bees are particularly attracted to flowers with bright colors, especially shades of blue, purple, and yellow. They may visit a variety of flower colors and shapes, but some of their favorites feature wide landing pads. Flowers with umbel-shaped inflorescences like those in the carrot family are great choices, as are compound flowers in the Aster family. In fact, if you want to support a diversity of native bees, one of the best plants you can incorporate into your landscape is Douglas Aster (Symphyotrichum subspicatum), which supports more than 50 native species. Plants with tubular flowers large enough for them to enter, such as foxgloves and penstemons, are attractive to many larger bees, as are lipped flowers like those in the mint family, the Lamiaceae. This includes many herbs cultivated for culinary purposes, such as lavender and thyme, which are popular with certain bees, in part due to their strong fragrance, which bees also use to locate flowers.

Plants for Butterflies & Moths

Butterflies tend to be attracted to bright colors from red to yellow, and pink to purple, and while they primarily rely on their vision to locate flowers, some species are also attracted to sweet scents. Because they have a unique feeding mechanism that involves uncoiling their long proboscis to reach into flowers for nectar, butterflies often prefer a sturdy place to land and take a drink. Coneflowers and black-eyed Susans are just two nectar-rich flowers that offer a wide landing pad of petals, and clusters of small, shallow blooms such as those found on lantana or verbena also function well for this.

In addition to nectar to feed their adult form, butterflies also rely on host plants where they can lay their eggs to provide food for their caterpillars. Including larval host plants in your garden will not only attract adult butterflies, but support their entire life cycle. Some common host plants for butterflies include our native Showy Milkweed (Asclepias speciosa) for monarchs and Tarragon Sagebrush (Artemisia dracunculus) for swallowtails.

In contrast to their butterfly kin, many moths are active primarily during the night. As such, it isn't surprising to find that many moth-pollinated flowers bloom specifically in the afternoon or evening hours. In addition to synchronizing their flowering time with their pollinators' schedule, many of these plants also feature flowers that are easily visible in low-light conditions. As such, moths tend to be attracted to white, pale pink, or light yellow flowers that shine in the moonlight. Fragrance also plays an important role in many moth pollination syndromes, as scents can signal that there is nectar available even on the darkest of nights.

Plants for Hummingbirds

There is perhaps no more beloved pollinator across the Americas than our native hummingbirds, which occupy a unique ecological niche. Here in Portland, we enjoy the presence of Anna's hummingbirds year-round, but other species are seasonal migrants, and all share similar predilections when it comes to flowers.

These highly specialized avian pollinators are tiny marvels that have co-evolved with different plant species to develop long beaks that can reach the nectar hidden deep inside long, tubular or funnel-shaped flowers. Hummingbirds rely on their excellent sense of vision to identify such suitable nectar-rich flowers. Thus, in addition to their uniquely shape, the blooms of many hummingbird-pollinated plants come in high-visibility hues of red, orange, and pink, which sit at the high-visibility end of the color spectrum. Lobelia cardinalis and Monarda didyma are two characteristic examples of hummingbird-pollinated plants native to North America that our local hummingbirds will visit, although they will also seek nectar from flowers that may not be pollinated by hummingbirds in nature, or even in their typical color scheme! Many Salvia guaranitica cultivars like 'Black and Bloom,' for instance, are hummingbird favorites in our gardens, in spite of featuring bright blue flowers. And we've even seen them visiting lavender, which is native to the Mediterranean region, oceans away from the nearest hummingbird.

Our Top Picks for a Semi-Native Pollinator Garden

Plant Name Plant Type Pollinator Type Larval Host Water Light PNW Native Status Bloom Time
Pot Marigold (Calendula officinalis) Annual Honeybees, Bumblebees, Native Bees, and Butterflies Average Moisture Part Sun Summer
Cosmos (Cosmos bipinnatus) Annual Honeybees, Bumblebees, and Butterflies Average Moisture Full Sun Spring and Summer
California Poppy (Eschscholzia californica) Annual Honeybees, Bumblebees, and Native Bees Larval Host Dry to Average Moisture Full Sun Native Summer
Alyssum (Lobularia maritima) Annual Native Bees and Butterflies Average Moisture Part Sun Spring and Summer
Camas (Camassia spp.) Bulb Honeybees, Native Bees, and Butterflies Larval Host Average Moisture to Wet Part Sun Native Spring
Saffron Crocus (Crocus sativus) Bulb Honeybees, Bumblebees, and Butterflies Dry to Average Moisture Part Sun Fall
Spring Crocus (Crocus spp.) Bulb Honeybees, Bumblebees, and Butterflies Average Moisture Early Spring
Thyme
(Thymus vulgaris)
Groundcover Honeybees, Bumblebees, Native Bees, and Butterflies Dry to Average Moisture Full Sun Summer
Yarrow (Achillea millefolium) Perennial Native Bees and Butterflies Larval Host Dry to Average Moisture Part Sun Native Summer into Fall
Anise Hyssop (Agastache foeniculum) Perennial Honeybees, Bumblebees, Native Bees, Hummingbirds, and Butterflies Dry to Average Moisture Full Sun Native Summer into Fall
Western Columbine (Aquilegia formosa) Perennial Bumblebees, Native Bees, and Hummingbirds Average Moisture Full Sun to Part Shade Native Spring into Summer
Tickseed (Coreopsis grandiflora) Perennial Native Bees and Butterflies Dry to Average Moisture Full Sun Summer
California Fuchsia (Epilobium canum syn. Zauschneria canum) Perennial Honeybees, Bumblebees, Hummingbirds, and Butterflies Dry Full Sun Summer into Fall
Hardy Geranium (Geranium 'Rozanne') Perennial Native Bees and Butterflies Average Moisture Part Sun Spring through Fall
Globe Gilia (Gilia capitata) Perennial Full Sun Native Summer
Sneezeweed
(Helenium autumnale)
Perennial Honeybees and Native Bees Larval Host Average Moisture to Wet Part Sun Native Summer into Fall
Hyssop (Hyssopus officinalis) Perennial Honeybees, Bumblebees, Native Bees, and Butterflies Dry to Average Moisture Full Sun Summer
Scarlet Beebalm (Monarda didyma ‘Jacob Kline’) Perennial Bumblebees, Native Bees, Hummingbirds, and Butterflies Average Moisture to Wet Part Sun Summer
Catmint
(Nepeta x faasenii 'Walker's Low’ and other cvs.)
Perennial Honeybees, Bumblebees, Native Bees, and Butterflies Dry to Average Moisture Full Sun Summer
Smooth Beardtongue (Penstemon digitalis) Perennial Honeybees, Bumblebees, Native Bees, Hummingbirds, and Butterflies Average Moisture Part Sun Summer
Black-eyed Susan (Rudbeckia hirta) Perennial Honeybees, Bumblebees, Native Bees, Butterflies, and Moths Average Moisture to Wet Part Sun Native Summer
Hardy Salvias (Salvia guaranitica and cvs.) Perennial Honeybees, Bublebees, Native Bees, and Hummingbirds Average Moisture Full Sun Summer into Fall
Stonecrop (Sedum spathulifolium) Perennial Bumblebees, Native Bees, and Butterflies Larval Host Dry to Average Moisture Part Sun Native Spring and Summer
Autumn Joy Sedum (Hylotelephium telephium ‘Herbstfreude') Perennial Honeybees and Butterflies Dry to Average Moisture Part Sun Summer into Fall
Canada Goldenrod (Solidago canadensis) Perennial Bumblebees, Native Bees, and Butterflies Average Moisture Part Sun Native Late Summer
Asters (Symphyotrichum cvs.) Perennial Bumblebees, Native Bees, and Butterflies Larval Host Average Moisture Part Sun Summer into Fall
Culver’s Root (Veronicastrum virginicum) Perennial Honeybees, bumblebees, Native Bees, Butterflies, and Moths Average Moisture to Wet Part Sun Spring and Summer
Oregano (Origanum vulgare and cvs.) Subshrub Honeybees, Bumblebees, Native Bees, and Butterflies Dry to Average Moisture Full Sun Spring
Manzanita (Arctostaphylos spp. and cvs.) Shrub Honeybees, Bumblebees, Native Bees, and Hummingbirds Dry to Average Moisture Full Sun Native Late Winter to Early Spring
Bluebeard (Caryopteris x clandonensis cvs.) Shrub Honeybees and Bumblebees Dry to Average Moisture Full Sun Late Summer into Fall
California Lilac (Ceanothus cvs.) Shrub Honeybees, Bumblebees, and Native Bees Larval Host Dry to Average Moisture Part Sun Native Spring
Tall Oregon Grape (Berberis aquifolium syn. Mahonia aquifolium) Shrub Honeybees, Bumblebees, Native Bees, and Hummingbirds Larval Host Dry to Average Moisture Full Sun to Full Shade Native Late Winter
Mock Orange (Philadelphus lewisii) Shrub Honeybees, Bumblebees, Native Bees, Hummingbirds, and Butterflies Larval Host Average Moisture Part Sun Native Spring
Red Flowering Currant (Ribes sanguineum) Shrub Bumblebees, Native Bees, and Hummingbirds Larval Host Dry to Average Moisture Part Sun Native Early Spring
Rosemary (Salvia rosmarinus) Shrub Honeybees, Bumblebees, and Native Bees Dry Full Sun Summer
Pussywillow (Salix discolor) Shrub Honeybees, Native Bees, Hummingbirds, and Butterflies Larval Host Average Moisture to Wet Part Sun Early Spring
Birch-Leaf Spirea (Spirea betulifolia) Shrub Native Bees and Butterflies Average Moisture Part Sun Native Summer
Cornelian Cherry (Cornus mas) Tree Honeybees Dry to Average Moisture Full to Part Sun Early Spring
Flowering Crabapple (Malus floribunda) Tree Honeybees, Bumblebees, Native Bees Larval Host Average Moisture Part Sun Spring

By incorporating these pollinator plants — and others — into your garden, you can create a vibrant and thriving ecosystem that supports the local pollinator population.