Before I propped it up on a convenient gravel bar, this young Arrowhead plant, Sagittaria brevirostra, was riding the creek currents on its way out of Blue Jay Barrens. I’ve never before collected anything but seed for my propagation studies, but I thought, since it was leaving the property on its own, I might has well transfer it to a pot and watch its development.
Survival of the specimen should be easy. The plant already possessed a healthy root system and a tuber packed full of energy.
I find the Arrowheads typically growing in mud banks developed on the insides of creek curves. These mud banks are transient, growing and shrinking at the whim of an unpredictable flood cycle. Sometimes, entire colonies of the plants are lost to a particularly violent flood. I imagine those plants travel downstream with the possibility of colonizing a new mud bank.
The plant was moved from the creek to a pot on May 20, 2015. Two months later, the pot was filled to capacity with plants. I emptied the pot and began to separate the plants in preparation for repotting.
Each new plant was equipped with a profusion of roots and rhizomes. It was easy to see that a single plant finding its way to a suitable site could quickly produce a large population.
What once filled a single pot, seemed still crowded when spread into three.
The original rescued plant was the only one of the bunch that was not growing tall and straight. When removed from the original pot, its roots were still near the surface of the soil as originally planted. The rest of the plants arose from rhizomes that had penetrated to the bottom of the pot.
By early August, the plants were flowering.
This Arrowhead species produces individual male and female flowers. A small fly visits this male flower. Small bees and flies were the most frequent visitors to the arrowhead flowers.
The individual fruits are clustered to form a spiked ball. Each fruit, achene, bears a single seed.
Shape of the mature achene is one characteristic used in the identification of species within the genus Sagittaria. Achene shape can vary greatly among different plants of the same species and also within a single flower, so one should never be comfortable with an identification based on a single achene.
This species has little tolerance for the cold and was zapped by the first hard frost. Plants in the creek grow where the creek water keeps the soil at a temperature above freezing.
I didn’t think the plants would survive their pots freezing solid, so they will spend the winter buried in a leaf filled pit with a loose covering of boards. It would take a record cold year for freezing temperatures to reach the pots stored here.