In winter, goldenrods are not golden. They are brown or pewter gray, the seeds lingering or gone, the cells dead, with no green remaining.
Yet they stand – at least some – and remind us of the tall weeds of summer. They stand because they are strong, as solid as their name Solidago. This winter in New England, one of our early snowfalls was wet and heavy, dragging many of the goldenrod stems to the ground. But not all. Some could withstand a weight that bent birch trees low.
Alas, these dead stems will not sprout again. They were the growth of the past year, not the future stems of the goldenrod. As the seeds mature and the stems die, the plants turn brown. Then they slowly fade to gray as the seeds disperse and the fragile remnants of the flowers fall away.
But spring will bring another chance for the stems to harbor life, another year to be part of the field community.
Once it becomes sufficiently warm (a warmth that you might consider cold), spiders will emerge from their winter dormancy and use the bare branches of dead inflorescences to build their webs. Two kinds of spiders use old goldenrods frequently, small orb weavers (the spinners of stereotypical spoke-and-spiral spider webs), and dictynids, a family of small, inconspicuous spiders that construct a tangled mishmash of a web and hide in the middle. I will try to get pictures of these spiders in the spring and share them. For now, imagine what they might look like on a dewy morning, the silk supported by the branches of dead flowers.
For much of the summer, dead goldenrod stems are among the tallest structures in a field, and there sit the spiders, waiting for their food. Flying insects, rising above the bulk of the green and growing plants, occasionally blunder into their webs. For a small spider, even a small insect is a good meal. Tall, dead stems give these spiders an excellent location for feeding.
There is another advantage for being on dead stems. They don’t attract one of the major enemies of spiders: spider-hunting wasps. Some wasps grab spiders and paralyze them with a sting. Then they store the helpless spiders in nests or cells where the wasp’s young will feed on the defenseless prey. Quite a few spiders live on flowers of goldenrod, and the wasps also feed on nectar, so blooming goldenrods provide one-stop shopping for the wasps.
But dead goldenrods have no nectar, and few spiders, so they are likely to be overlooked by the wasps. That’s a good thing if you’re a small spider.
Late in the summer, another kind of creature will sometimes climb up on dead goldenrod stems. These are the immature stages of small beetles in the genus Exema. The larvae feed on goldenrod leaves, but they look like the turds of large caterpillars because they use their own turds to build a dark brown case around themselves for protection (visual and physical). They hide inside their own excrement and grow slowly during the summer. As the season wanes, they are ready to pupate, and that’s when they seek a location that won’t be disturbed. Some of them wander on to the dead stems of goldenrods from years past. Perfect. The gray stems don’t have pollen or nectar to attract parasitic or predatory insects. While the enemies of the beetles go elsewhere, the pupae on the dead stems can develop in peace.
Standing dead stems do not remain standing forever. When they finally topple – and they all topple eventually – they will decay back into the soil. It’s part of the life cycle of a perennial herb.
February 1, 2021 at 10:09 am
Never realized the strategic drama for small spiders staking a claim on dead Golden Rod.
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