We are on the cusp of continuous warm nights.   Warm soil temps will take a few more weeks.   Recently, I had a gardener ask me about their hearty hibiscus that was planted last year.  They were worried it wasn't coming back; they didn't see any sign of life yet.   In Minnesota, gardeners often start to freak out a bit if they don't see signs of life during these first sunny days in May.   But remember, warmer weather plants won't start to do their thing until soil temps warm up.  The soil temp has about a 2-3 week lag on the night time air temp. We are still about a week away from warm nights - nights over 60 degrees.  Warm soil will happen at the end of the month or the beginning of June.   So, don't be alarmed if some of your summer perennials still seem dormant, that's because they are waiting for warmer soil temps to get going.       Brevities #OTD On this day in 1742, Jean Senebier, a Swiss pastor and botanist, is born. Where would we be without Senebier? Still breathing... but not appreciating the role Senebier played in getting the world to realize that carbon dioxide is consumed by plants and in turn, plants produce oxygen as part of the process of photosynthesis. Senebier’s work is important because he had learned the function of leaves: capturing carbon for food. Prior to Senebier, the purpose of leaves  and what they did for plants and people was unknown. It was Jean Senebier who said,  "Observation and experiment are two sisters who help each other."   #OTD Today, in 1806, along the banks of Idaho’s Clearwater River, Lewis and Clark discoverd  the Nine-leaf lomatium, Lomatium triternatum. A species of flowering plant in the carrot family and known by the common name nineleaf biscuitroot, the nine-leaf lomatium is so-named because each leaf divides into three narrow leaflets that, in turn, divide into three more (triternatum, from the Latin, means “three times three”). Lewis and Clark collected many varieties of lomatiums which are found only west of the Mississippi River. Lomatiums are used by herbalists as a remedy for viral illnesses. In 2018, the NIH reported the case of a woman who had taken lomatium extract - marked LDM-100 - for the flu and ended up with a severe rash all over her body for a week.  The title of the article, "Worse than the Disease? The Rash of Lomatium Dissectum"     #OTD The naturalist and Alexander Von Humboldt died today in 1859, he was 89 years old. In 1806, Friedrich Georg Weitsch painted his portrait, in 1806, two years after he returned from his five-year research trip through Central and South America. Humboldt didn't go alone; he was accompanied bythe French botanist Aimé Bonplant in 1799. Weitsch painted a romantic, idealized vista of Ecuador as the setting for the painting. Humboldt had climbed the Chimborazo Mountain in Ecuador, believed at the time to be the highest mountain in the world, so perhaps Weitsch imaged Humboldt viewing the landscape from Chimborazo. Surrounded by a jungle paradise, a large palm leaves shade Humboldt's resting spot.In the painting, a very handsome Humboldt is seated on a large boulder, his top hat is resting upside down on the boulder behind him. Weitsch shows the 37-year-old Humboldt wearing a puffy shirt that would make Seinfeld proud, a pinkish-orange vest, and tan breeches.  In his lap, he holds open the large leather-bound Flora he is working on and in his right hand he has a specimen of  "Rhexia seciosa" (aka Meriania speciosa).  A large barometer leans against the boulder in the lower left corner of the painting. It symbolized Humboldt’s principle of measuring environmental data while collecting and describing plants. King Ferdinand was so pleased with the portrait (which he had hung in the Berlin Palace), that he ordered two more paintings to be made featuring Humboldt's time in the Americas. Humboldt was a polymath; he made contributions across many of the sciences. He made a safety lamp for miners. He discovered the Peru Curre