Grow your own bee homes by planting hollow-stemmed plants for nesting bees!
Milkweed and other native pollinator plants with pollen- and nectar-rich flowers are some of the best plants to grow in a pollinator garden. But if you’re keeping a bee habitat and want to make your garden even more attractive to native bees and other pollinators, try growing a few hollow or pithy-stemmed plants in your landscape too. Not only do nesting bees use hollow-stemmed plants for egg laying and hibernation, but plants with hollow stems will also provide shelter for beneficial insects and other wildlife!
Here are some of the best plants for bees that have hollow or pithy stems, plus a few quick pollinator gardening tips to help you grow your own bee homes for hibernating bees and other wildlife!
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Small, native carpenter bees often nest in hollow plant stems.
How Do Plants with Pithy or Hollow Stems Benefit Pollinators?
While many people associate bees with bee hives, most of the native bees in North America are actually solitary species that don’t live in hives at all! Some of these bees burrow in the ground or nest in cavities in dead trees (known as “snags.”) But other solitary bees hibernate and lay eggs in bee hotels and plants with hollow or pithy stems.
Installing a pollinator house and sowing natural sheltering plants with hollow stems encourages native bees to stick around your garden and provides a safe place for pollinators to weather out winter storms. Although hollow stems can benefit a wide range of wildlife, they’re especially valuable for:
Leafcutting bees
Mason bees
Small carpenter bees
Carder bees
Resin bees
Spiders
Stem-boring moths
Solitary wasps
Tip: Hollow stemmed plants have open cavities in the center, while pithy stems have soft centers that insects can easily excavate for nest building!
Hollow stems can also be harvested to make DIY bee houses!
10 Best Flowers for Bees with Hollow or Pithy Stems
Stem-nesting pollinators come in different sizes, so it’s no surprise that they’re drawn to different sized plant stems. To make your garden as appealing to pollinators as possible, select a variety of native plants that bloom at different times and have different stem sizes. Sowing plants in groups of three or more is also wise since it helps pollinators spot nesting sites from a distance!
Joe Pye weed plants can grow over 6 feet tall, so give them room to grow!
1. Joe Pye Weed (Eutrochium spp.)
Hollow stem Joe Pye weed is commonly grown in pollinator gardens because it produces broad, nectar-filled flowers, which make easy landing pads for large pollinators. However, this North American native plant also has hollow stems, which provide habitat for nesting pollinators. A fine choice for rain gardens, Joe Pye weed can handle soggy soil like a champ too!
Native to North America?: Yes Light needs: Full sun to part shade Water needs: High
Purple flowering raspberries can be used in hedgerows.
2. Purple Flowering Raspberry (Rubus odoratus)
With oversized, magenta flowers, purple flowering raspberry has a distinctly tropical look, but it’s actually another North American native. This plant produces edible berries, but its berries are smaller and not as tasty as raspberries produced by standard raspberry plants. Beyond its hollow, sheltering stems, this pollinator favorite provides food for bumblebees and honeybees, as well as songbirds!
Native to North America?: Yes Light needs: Full sun to part shade Water needs: Average
Grow milkweed in sheltered, sunny spots so pollinators don’t get buffeted around by strong winds.
3. Milkweed (Asclepias spp.)
North America has many types of native milkweeds, but here in Maine, we’ve got four: common milkweed, poke milkweed, swamp milkweed, and butterfly weed. While milkweed plants are most famous for being hosts of monarch butterflies, they also have hollow stems for nesting bees and plenty of nectar and pollen for other insects. Swamp milkweed is a fine choice for water gardens, while common milkweed thrives in drier soil.
Native to North America?: Yes Light needs: Full sun for most species Water needs: Depends on variety
Elderberry berries also attract wild birds!
4. Elderberry (Sambucus spp.)
Many gardeners grow elderberry for syrup-making, but elderberry plants are also great for pollinators and wild birds. Elderberry flowers entice all sorts of pollinators to visit, while birds nibble on the berries, and pollinators use the plant’s hollow stems for shelter.
Native to North America?: Yes Light needs: Full sun Water needs: Average
Hummingbirds can’t resist cardinal flowers!
5. Cardinal Flower (Lobelia cardinalis)
Aptly named cardinal flowers have bright red blooms that look like the plumage of crimson cardinal birds. Like Joe Pye weed, cardinal flowers grow best in moist soil, so plant them in a soggy spot or water them often and add mulch to keep their water-loving roots from drying out!
Native to North America?: Yes Light needs: Full sun to part shade Water needs: High
Many wild birds will nibble on native plant seeds if you let them.
6. Anise Hyssop (Agastache foeniculum)
Although anise hyssop is often grown for its fragrant and edible, licorice-flavored leaves, this flowering beauty is also a top-notch pollinator plant! Tall, purple, spire-shaped flowers invite in pollinators of all sorts, while nesting bees find safe shelter in the plant’s hollow stems.
Native to North America?: Yes Light needs: Full sun to part shade Water needs: Average to low
Ironweed stems aren’t hollow, but they still make for excellent nesting!
7. Ironweed (Vernonia spp.)
Ironweed has pithy, rather than hollow, stems but nesting bees still use those pithy parts to make nests for their babies! This hardy, North American native is named for its tough-as-nails nature, but its pretty purple flowers will charm you and pollinators too.
Native to North America?: Yes Light needs: Full sun to part shade Water needs: High to average
Woodland sunflowers are a native plant option that tolerates lower light gardens.
8. Sunflowers (Helianthus spp.)
There are a number of native sunflowers in North America, although gardeners are most familiar with big-bloomed sunflowers that produce lots of edible seeds. Most native sunflowers have more petite flowers, but they still have plenty of charm and they attract pollinators with their nectar-filled flowers and hollow stems.
Native to North America?: Yes Light needs: Full sun for most species, but some native varieties can handle shade Water needs: Average
Wild bergamot and scarlet bee balm are two popular plants for pollinator habitats.
9. Bee Balm (Monarda didyma or Monarda fistulosa)
Also known as wild bergamot, bee balm flowers delight with their stately height and sprays of purple or magenta petals. Aside from their hollow stems and pollen-filled flowers, these plants also produce edible leaves and petals that taste somewhat like oregano and can be used in tea!
Native to North America?: Yes Light needs: Full sun Water needs: Average
Mountain mint’s silvery leaves have ornamental appeal too. This one’s just about to bloom!
10. Mountain Mint (Pycnanthemum spp.)
Mints are rather notorious for their spreading nature, but mountain mint is a North American native that doesn’t grow as aggressively as its minty cousins. This plant grows taller than most mints (maxing out around 3 feet tall) and its silvery leaves can’t help but impress in mixed flower beds. Bees love supping from mountain mint flowers and nesting in its hollow stems… but this plant is also edible!
Native to North America?: Yes Light needs: Full sun to part shade Water needs: Average
Just like in bee hotels, bees cap off hollow plant stems after filling the hollow cavities with eggs and bee bread!
How Do Bees Use Hollow-Stemmed Plants
To understand how hollow-stemmed plants help pollinators, it’s important to know how bees use these plants (and bee hotels!) in the first place. Most nesting bees divide hollow plant stems into smaller chambers by building partitions in the stem with plant debris. Then, they lay their eggs in the stem chambers from spring through fall, place a bit of “bee bread” (made of nectar and honey) inside to feed developing larvae, and seal up the stem chambers with more plant debris.
Once the bee eggs hatch, bee larvae eat the bee bread and overwinter in plant stems before emerging in spring through early fall. Because it takes some time for bees to emerge, lower sections of plant stems need to be left in place for about 2 to 3 years. During the growing season, leaves should cover up the stem stubble for a tidier plant look and, eventually, the old stems will degrade back into the soil.
Tip: If you’re worried about stem stubble bothering your neighbors, installing a “pollinator garden” sign can let your neighbors know your gardening style has a purpose. If you can’t leave all the plant stems in place, just a few intact stems can help too!
Leaving several inches of hollow stems provides safe nesting spots for native bees.
How to Grow Your Own Bee Shelter
Now that you know how bees use hollow-stemmed plants, follow along with these tips to grow your own bee homes with hollow-stemmed plants!
Year 1:
Step 1: Plant your flowers. Perennial plants are usually planted in spring or fall when the weather is mild. Be sure to research the specific care needs of the plant’s you’d like to keep before planting.
Step 2: Let the plants overwinter. Allow your plants to grow through one growing season and avoid the temptation to cut the stems back in fall. Bees don’t nest in actively growing plants, but in-tact seed heads should attract wild birds!
Year 2:
Step 3: Cut the stems back. In early spring (around March), cut the stems back to about 6 to 24 inches above the soil. This opens up the stem cavity and invites pollinators to lay their eggs inside when they emerge from hibernation.
Step 4: Wait. Leave the stem stubble in place through the year so that bees can nest inside. As your plants fill in in summer, bare stems should be covered up by leaves.
Year 2-3:
Step 5: Repeat. Leave the stems produced during the second growing season in place during winter and then clip back those stems in early spring. Bees should emerge from the first year’s growth of stems, while a new generation of bees will be developing in the second year stems.
Repeating this process for seasons to come will yield a continuous growth of new nesting spots for native bees!
Butterfly weed is an even showier alternative to common milkweed… with bright orange flowers!
Quick Bee Gardening Tips
Growing pithy and hollow-stemmed plants is one way to help out native bees. But here are a few more tips to ensure your garden is as bee-friendly as can be!
Add a water source. A solar-powered water fountain added to a bird bath provides pollinators with a safe place to drink.
Install a bee hotel. Just because you’re growing hollow-stemmed plants doesn’t mean you can’t add a bee hotel too!
Leave the leaves. Leaving plant stems in tact through winter provides nesting spots for bees, but some pollinators also overwinter in old leaf litter. Unless leaves are infested with pests or disease, consider leaving some leaves in place until spring to provide nesting spots for critters.
Avoid pesticides. Many pesticides don’t discriminate between bees and plant pests. Opt for organic pest control options whenever possible and use companion planting and crop rotation to keep pests at bay.
