Harvest season is here, so now is the time to save reeds and stems for bees to use next spring. Since I started saving various stems a few years ago, I discovered that cavity-nesting bees really like all-natural materials, and they fill cut stems quickly and uniformly.
Plants vary from place to place
The type of stems you have will depend on where you live, but I’ve had good success with lovage, teasel, drumstick allium, joe-pye weed, elderberry, and blackberry. I cut them in six-inch lengths and let them dry in the sun for a week or more. Some people like to cut just above a node in order to get a natural back end. I prefer to cut them without nodes so they fit in a can easier, but either way will work. If they don’t have a closed-off back end, the bees will build one by themselves.
The length, too, can be variable. But remember that most cavity-nesting bees lay male eggs in the last three or four positions within a tube, so if the tube is too short, you end up with mostly male bees. The females will only go so far into a tube before they build a back wall, so it’s hard to make the tubes too long. With that in mind, err on the side of too long instead of too short when you design your bee housing.
More variety attracts more species
Also, if you want to attract a range of species, be sure to use some hollow tubes and some pithy tubes. The ones shown below are all hollow (lovage and drumstick allium) but others like blackberry and elderberry are filled with soft pith. Certain bee species, such as the small carpenter bees in genus Ceratina, will only build in a tube that contains pith. This is because they chew the pith into a paste and use it for partitions.
Mason bees and leafcutters usually opt for the hollow kind of tube, so a variety of types will attract a larger selection of bees. The inside diameter can start pretty small (as for Ceratina and small Osmia) and can range upward to about 1/2-inch. I usually have a few very small, such as 1/16-inch, and a few very large, such as 9/16-inch, but most are around 1/4- to 5/16-inch. If you have too many tubes with large diameters stuck in a container, you will find bees using the interstitial space for nesting instead of the tubes. To prevent that, fill those spaces with smaller tubes to take up the slack.
I like to use a screened inner cover (shown below) for drying stems because you get good airflow on all sides, which makes the drying quick and uniform. If you don’t have something screened on the bottom, just roll the the stems when you think about it. After they are dry, stack them in a cardboard box until spring. Be sure to keep them in a dry place so they don’t get moldy.
I’m sure everyone has a plant that works well for pollinators in his or her area. How about you? What species make good housing where you live for both pith and no-pith bees?
Honey Bee Suite
You don’t say what they are for? What do you do with the stems in the spring to attract pollinators?
You put them into some type of pollinator housing, such as a wooden box or tin can. I have lots of articles here about pollinator housing that explain sizing and position.
I’ve used hollow tubes from the old spirea in my yard, from tiny holes up to about a quarter inch. They’re all used. I find that the natural tubes, whether homemade or purchased, are much more popular than paper straws or cardboard tubes. I’ll have to try blackberry canes. Heaven knows there are enough around!
I will have have to take a look at spirea. I had no idea it had hollow stems. Thanks!
De-budding the garden I harvested tubes from Dahlia and Fox Glove stems – both plants have nicely hollow stems that taper from 10 mm down to the smallest diameter. Have yet to raise mason bees or other non-honey bees but will get this falls garden waste working this coming spring. Also a few from our nearby blackberry patches. I’ll check out a few ditch lines for Spirea.
Great, that helps. Your post was not connected to any of those articles.
We have 6 different metal carports on the property with horizontal spaced 2×6 wood boards and corrugated metal siding attached to the boards. Our llamas use the shelters. The mason bees absolutely go gaga over the spaces in the corrugation where it lays against the wood boards. On any given warmer spring day you can walk in and hear nothing but buzzing as they do their thing. And given how gentile they are, they never have caused any problems for us or the animals. Part of the go to I think is that those corrugations also gather tiny pieces of waste hay/straw that we just leave for them.
I use hollyhocks and Maximillian sunflowers. I’ve been leaving them standing over the winter based on some advice for our natives here in New Mexico, but I have enough stalks to do both methods. I just heard a talk by Olivia Messinger-Carril (Bees in Your Backyard) and she said the same as you, Rusty, that proper length is important for male/female balance. Most of the bee hotels we’re seeing for sale these days contain tubes that are too short and that to create your own is easier and more suited to the bees. New Mexico’s natives are largely ground dwellers, so we’re being encouraged to leave some bare spots–the harder the better–in our gardens, and to educate landscapers to consider native bee habitat before they pave or plant border to border.
That’s a really good point about the ground dwellers. By far, most bee species are ground dwellers, not just in New Mexico but all over. Most estimates say about 70%. So leaving patches of bare ground is one of the very best things you can do to attract natives. Some like it level and flat, some like embankments — it all depends on the species that live in your area.
I like Phragmites reeds. A wide variety of inside diameters can be found and the smaller ones have a good amount of pith. Opening them to harvest cocoons, should you want to do that, is also easy.
I never thought of Phragmites. Good to know.
Rusty – would stems from bee balm & Annabelle hydrangea work? (Annabelle is a white native shrub That puts up new stems from ground level each year & then blooms on the new growth.)
I’ve never tried either, but I certainly would if they look right. For some reason, I never can get my bee balm to grow. Time to try again.
Annabelle hydrangea is a nativar. A nativar is a cultivar of a native plant plant that was derived from a native species by humans. Annabelle hydrangea does NOT exist in nature. It is not a native species. More troubling, Annabelle’s flowers are sterile; they produce neither nectar nor pollen. If you are interested in helping pollinators, shrubbery that deprives them of pollen and nectar makes butterflies and bees work harder to find it. Annabelle defeats your purpose. Instead plant true native hydrangeas that do provide nectar and pollen and are much more beautiful than Annabelle. Regards, Charlotte Adelman, Co-Author – Midwestern Native Shrubs and Trees.
You can read my article on nativars in the current issue of 2 Million Blossoms.
Would bamboo sections be useful? Do you stand them upright in the can or box with the opening upwards? Should it be protected from the rain?
I fill the can and then lay the whole thing on its side. And yes, protect them from the rain.
I used the stems from daylilies, and the mason bees took to them right away. Once the tubes were filled for the season, I placed them in my garage for storage until next spring. However, my garage gets very hot in the summer, often feels more hot in there than outside. Will too much heat harm these developing mason bees? Thank you.
They will probably be fine as long as they don’t get hot in the winter months.