Rare plant seeds are….rare
Drought can cause many plants to “give it a miss” when it comes to producing seeds. If a plant lacks adequate water resources and is stressed it can affect the quantity and the quality of seed that it can make.
This is even more pronounced with many of the rare plant species that we work with. Sometimes what makes a plant rare is the overall reduced capacity for that particular species to reproduce, thus making it uncommon on the landscape.
This season has been particularly challenging in the rare plant seed hunting department. As part of the Center for Plant Conservation (CPC) we try to bulk up the seed storage reserves of approximately 5-10 different species per year. This season I had two beauties to find, both species I knew well and knew of decent populations to try and target. One did ok, the other…not so much.
The Verde Valley Sage (Salvia dorrii ssp. mearnsii) – which is pictured above – is a gorgeous member of the mint family with a pungent scent and striking floral color. This sage is an herbaceous perennial which flowers in the spring and sets seed in the early summer. My population this year was flowering quite nicely, showing off its lavender flowers and magenta sepals/bracts. I was able to time the collection just right before the summer sun got too brutal and before the seeds fell out onto the ground. Species #1 – check.
Rusby’s Milkwort (Polygala rusbyi) is a tiny, often nondescript perennial that loves the white limestone soils of the Verde Valley. This plant flowers in the spring, sets seed, then can completely die back during the late summer through the winter and disappear from the landscape while it waits underground for the spring to return. It can be hard to relocate individuals once the flowers have gone. I had a great population located with hundreds of plants in a large area, with about ½ of them having flowers. After monitoring it over time, I noticed the summer came on dry and hot and the flowers seemed to just shrivel and fall off. When it was seed collecting time, I only was able to find 8 seeds total from over 1000 plants. Not great. Species #2 – wha whaaaa. Will have to retry again in 2026.
Such is the life of a rare plant conservationist!
Sheila C. Murray is the Conservation Botanist at The Arboretum at Flagstaff.
