Hello Gardeners, I’m Amanda McNulty with Clemson Extension and Making It Grow. Elderberry stems are semi-woody, the interior is filled with pith. The late John Fairey, renowned botany professor at Clemson, told his students that this pith was collected and used to pack delicate scientific instruments and by repairmen to hold tiny parts of watches, back in the day when people actually fixed mechanically-run timepieces. Mason bees and other insects, however, have long used them as places construct egg-laying or brood chambers. So if you have elderberries in your landscape, don’t be tidy and cut them back each year but leave those above ground structures for those important solitary bees. Another option is to put them in a mulch pile, you can order a Pollinator Friendly Habitat sign from the Xerces Society, x-e-r-c-e s. Read their page about building a better mulch pile for more ideas about making your yard pollinator friendly.