Wednesday, September 16, 2015

Rosinweed

The last of the rosinweed flowers are blooming. The least-mentioned (at least in my world) Silphium, rosinweed is probably often mistaken for one of the many sunflower species currently in bloom... though its leaves do have the stiff sandpapery-ness of the other Silphium, they aren't as large or interestingly shaped.  Plus, the plant isn't nearly as tall as its siblings to attract notice.

These DYCs bloom earlier and finish before the numerous sunflower species, which are still in peak bloom while these peter out.  (The stem I drew had 3 green seedheads-to-be and one actual still-flowering flower... but several of its petals were curled up in the throes of death.)   Another interesting difference that I just learned: sunflowers and most other disk and ray composites have fertile disk flowers and often sterile ray flowers.  Rosinweed is the opposite -- all those little flowers in the  middle can't make seeds (that's probably why the middle of the seedhead-to-be is fuzzy... the flaky Silphium seeds will form a ring around them); only the ray flowers produce viable seeds.  Who knew?

Rosinweed is also extremely tolerant of drought and poor soils, meaning it can be a good choice for gardeners with those conditions... but that if we planted it it would probably grow 8 feet tall (which is 3 feet taller than it's "supposed" to get) because that is what seems to happen in our yard.  We had an interesting conversation this weekend with our native plant provider, in which we mentioned that most of the native prairie plants that we have cultivated seem to grow MUCH taller than their estimated heights, making our garden somewhat of an impassable jungle at the moment despite carefully planning NOT to have many really tall things.  Apparently those estimates are often based on poor soil conditions, and when you put these plants in good, well-amended soil, well... they get really tall.  So now we know.

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